native/docs/parity/09-jmap-core-sync-security.md

JMAP client core, live sync, offline/outbox, network & error handling, security, S/MIME & encryption-at-rest

Summary

RN's JMAP client (src/api/jmap-client.ts, 615 lines) is a thin transport: session discovery, Basic/Bearer auth with proactive+reactive OAuth refresh, 401/429 mapping, capability lookups, blob URL templating. It lacks essentially every robustness layer WEB grew between 1.4.5 and 1.9.2: request deadlines (#702), maxConcurrentRequests back-off (#780), transient-network retry, rate-limit pause/resume, maxObjectsInSet/maxSizeUpload awareness, relative-session-URL resolution, keep-alive ping with connection-lost signalling, and first-touch serialisation (#907). Most RN API functions index methodResponses[0][1] without checking for error / notUpdated, which combines badly with the outbox (a rejected mutation is treated as done). Live sync is the weakest area: there is no AppState handling at all, react-native-sse never re-polls after a network error (status 0), the SSE stream captures the Authorization header once (stale after OAuth refresh), the push effect does not re-run on account switch (stream stays bound to the previous account), and a client-cert user gets no SSE and no polling fallback. Security posture is decent (SecureStore, hardened WebView, no secret logging) but has gaps: Linking.openURL with unvalidated schemes from contact/calendar data, Math.random for OAuth state and TOTP secret, http:// server URLs accepted, AsyncStorage mail cache in Android auto-backup, password change leaving stored credentials stale (locks the account out). S/MIME is a mock UI; encryption-at-rest is read-only; List-Unsubscribe is absent.

Findings

JMAP client core (request pipeline)

• No request deadline: a stalled socket hangs send/save forever (#702) — P1 — bugfix-parity — fixed in 0b1c240

  • What WEB does: timedFetch puts a 30 s deadline on response headers (300 s for blob transfers), throws RequestTimeoutError, never retries a timed-out non-idempotent request (lib/jmap/client.ts:629-634, 786-816, 836-846; changelog 1.7.x "Time out stalled JMAP requests so a send can't hang forever (#702)").
  • What RN does: request(), fetchSession(), fetchBlobArrayBuffer() call secureFetch with no AbortController/timeout (src/api/jmap-client.ts:405-447, 363-386, 568-584). RN fetch has no timeout of its own; iOS suspends sockets in background and hands back dead pooled connections on resume, so the composer's Send stays disabled indefinitely. Only the client-cert native path has a 30 s timeout (src/lib/client-cert.ts:250).
  • Fix hint: wrap every fetch in jmap-client.ts with an AbortController + setTimeout (30 s API, 300 s blob), throw a RequestTimeoutError subclass, and make isTransientNetworkError classify it as transient only for idempotent ops (never re-send EmailSubmission/set).

• maxConcurrentRequests refusal (400 jmap:error:limit) is a hard failure (#780) — P2 — bugfix-parity — fixed in 0b1c240

  • What WEB does: isConcurrentRequestRefusal + 3 jittered retries (200/400/800 ms) before failing (lib/jmap/client.ts:462-473, 1136-1146; changelog "Keep the folder tree when a refresh burst hits maxConcurrentRequests (#780)").
  • What RN does: any non-OK status throws JMAP request failed: 400 (src/api/jmap-client.ts:442-444). A single StateChange fans out to handleStateChange in email, contacts and calendar stores concurrently (App.tsx:391-396), each of which issues 1-3 requests, so Stalwart's default ceiling of 4 is hit in ordinary use; the folder tree is preserved (src/stores/email-store.ts:604-612) but the refresh is dropped.
  • Fix hint: port isConcurrentRequestRefusal and the retry loop into JMAPClient.request(); read the body text before deciding.

• No transient-network retry — P2 — missing — fixed in 0b1c240

  • What WEB does: retries once after 1 s on a fetch TypeError unless already reconnecting or timed out (lib/jmap/client.ts:836-846).
  • What RN does: request() propagates the raw TypeError("Network request failed") (src/api/jmap-client.ts:427); isTransientNetworkError recognises it (src/lib/network-error.ts:48-63) but only the outbox uses that.
  • Fix hint: single retry for GET/idempotent bodies in request(); keep non-idempotent (EmailSubmission/set) un-retried.

• 429 handling: no rate-limit state, no pause of live updates, HTTP-date Retry-After becomes NaN — P2 — partial — fixed in 0b1c240 (rate-limit window + onRateLimit; SSE/polling pause via the window check in request())

  • What WEB does: setRateLimited blocks all requests until the window ends, tears down and re-arms push, notifies UI via onRateLimit and a throttled toast event; parseRetryAfter handles seconds and HTTP-date, caps at 5 min, defaults 60 s (lib/jmap/client.ts:820-826, 848-852, 7421-7486; stores/auth-store.ts:208-226).
  • What RN does: throws RateLimitError(ms) (src/api/jmap-client.ts:436-440) where parseInt of an HTTP-date yields NaN*1000; nobody catches it (grep: only tests). SSE reconnect (5 s), polling (5 s), outbox flush and stores keep hammering the server during the window.
  • Fix hint: add rateLimitedUntil to the client, short-circuit request() while limited, close SSE/polling and re-arm after the window, expose to OfflineBanner.

• HTTP error body and cause not surfaced; JSON parse unguarded — P3 — partial — fixed in 0b1c240

  • What WEB does: error message includes status + first 200 chars of body, JSON parse failure mapped to a clear error (lib/jmap/client.ts:1147-1156; changelog "Surface the underlying network error cause in passthrough failures").
  • What RN does: JMAP request failed: ${status} and response.json() unguarded (src/api/jmap-client.ts:442-446); loadAccount wraps into NetworkError but request() throws bare TypeError.
  • Fix hint: read text, include in message, wrap JSON.parse; throw NetworkError from request() too.

• Method-level error / notUpdated / notDestroyed unchecked in most RN API functions — P1 — rn-only-bug — fixed in ccbe67c (mail/identity/push; contacts, calendar, files done by their agents)

  • What WEB does: mutations inspect notUpdated/notDestroyed (lib/jmap/client.ts:2282-2286 moveEmail; 3290-3345 sendEmail), reads check the method name before indexing (1207-1208).
  • What RN does: res.methodResponses[0][1].list / .ids indexed blindly in getMailboxesWithState (src/api/email.ts:61-70), getEmails (322-327), getEmailsWithState (338-343), getThread (428-434), queryEmails (244-260), getIdentities (src/api/identity.ts:5-12); Email/set mutations never look at the response: setEmailKeywords (email.ts:436-445), moveEmail/moveEmails (447-480), deleteEmails (483-495), setKeywordsForEmails (527-539), restoreEmailMailboxes/setEmailMailboxes (541-575), destroyEmails (581-586), updateIdentity/deleteIdentity (identity.ts:27-45). An ['error', {type:'forbidden'}] response makes the read path throw a TypeError (classified transient by network-error.ts:51, see outbox finding) and makes the write path report success: the outbox removes the entry (src/stores/outbox-store.ts:199-200), the optimistic list/cache edit is never reverted.
  • Fix hint: add a shared requireMethodResult(res, callId) (like resultFor in src/api/account-security.ts:59-67) and an assertSetResult(body, ids) that throws on notUpdated/notDestroyed; use them in every src/api/*.ts function.

• Email/get and Email/set not split to maxObjectsInGet/maxObjectsInSet; no getMaxObjectsInSet — P2 — bugfix-parity — fixed in ccbe67c

  • What WEB does: batched(ids, getMaxObjectsInGet()) for gets (lib/jmap/client.ts:713-727), getMaxObjectsInSet() for batchMarkAsRead, batchDeleteEmails, batchMoveEmails, batchUpdateKeywords (1885-1894, 2109-2136, 1953-1961, 4194-4197; lib/jmap/request-limits.ts; changelog "Split requests to stay inside the server's advertised limits").
  • What RN does: getEmailsWithState (src/api/email.ts:338-343) is called from the incremental refresh with an unbounded addedIds + updatedIds list (src/stores/email-store.ts:848-857), getMailboxesByIds after Mailbox/changes is unbounded (email.ts:114-127, store 565-567), listScheduledEmails fetches up to 200 ids in one get (email.ts:922-928); setKeywordsForEmails, moveEmails, restoreEmailMailboxes, destroyEmails, archiveEmails put every selected id into one Email/set (no maxObjectsInSet accessor exists in jmap-client.ts). Only fetchEmailsChunked (email-store.ts:371-381), getEvents/getContacts (src/api/calendar.ts:214, contacts.ts:45) and offline-sync.ts:92 chunk. Over-limit requests fail whole, so a long offline gap (many updated ids) breaks the incremental refresh until the snapshot is dropped.
  • Fix hint: add getMaxObjectsInSet() + a batched() helper to jmap-client.ts; apply in the listed functions.

• maxSizeUpload / maxSizeRequest ignored — P3 — missing — fixed in 0b1c240 (accessors; enforced by the files/composer agents)

  • What WEB does: getMaxSizeUpload() (lib/jmap/client.ts:4179-4182) gates attachment/file uploads with a clear message (changelog 1.6.x "Use dynamic server-configured maximum upload sizes"; "maxSizeRequest").
  • What RN does: no reference to maxSizeUpload anywhere (grep -rn maxSizeUpload src empty); uploadBlob (src/api/blob.ts:5-62) surfaces an opaque Upload failed: 413.
  • Fix hint: expose getMaxSizeUpload() and check before File(uri).bytes() in blob.ts/ComposeScreen.

• Relative session URLs are not resolved (37f830da) — P2 — bugfix-parity — fixed in 0b1c240 (unified-inbox.ts with the mail-list agent)

  • What WEB does: rewriteSessionUrl rebases both absolute and relative (/jmap/) apiUrl/downloadUrl/uploadUrl/eventSourceUrl onto the login origin without touching {accountId} templates (lib/jmap/client.ts:1091-1114; changelog 1.9.x "Resolve relative session URLs without corrupting URI templates").
  • What RN does: rewriteSessionUrls only rewrites when extractOrigin(url) matches ^https?:// (src/api/jmap-client.ts:320-340); a relative apiUrl is returned unchanged and fetch('/jmap/') then fails with "Network request failed". Same gap in src/api/unified-inbox.ts:55-60. (RN correctly avoids new URL() so templates are not corrupted.)
  • Fix hint: in rewrite(), when extractOrigin is null and the string starts with /, return serverOrigin + url.

• Capability check uses the broad principals URN, not principals:owner (44360024) — P2 — bugfix-parity — fixed in a0ce925

  • What WEB does: declares urn:ietf:params:jmap:principals:owner in using only when that exact capability is advertised in session or account capabilities (lib/jmap/client.ts:4689-4698, 6472; changelog "Check the specific capability a request declares (principals:owner), not a broader one").
  • What RN does: supportsSharing() checks CAPABILITIES.PRINCIPALS (src/api/files.ts:23-25) and then pushes PRINCIPALS_OWNER into using (files.ts:40-43). A server advertising principals but not principals:owner rejects every FileNode request with unknownCapability.
  • Fix hint: check hasCapability(CAPABILITIES.PRINCIPALS_OWNER) || accountCapabilities[...] before adding it.

• PatchObject pointer keys not JSON-Pointer escaped (5c484af1) — P3 — bugfix-parity — fixed in ccbe67c

  • What WEB does: keywordPointer()/pointerToken() escape ~ and / (lib/jmap/patch-pointer.ts:39-55); mailbox moves use a whole-map replacement (lib/jmap/client.ts:66-74).
  • What RN does: moveEmail/moveEmails build mailboxIds/${id} pointers unescaped (src/api/email.ts:456-457, 473-474). Stalwart ids never contain /, so exposure is limited to non-Stalwart servers; keywords are always sent as a whole map (email.ts:436-445), so tag names with / are safe.
  • Fix hint: add pointerToken() or switch moveEmail(s) to the full mailboxIds replacement RN already uses in restoreEmailMailboxes.

• Send: message created directly in Sent instead of Drafts + onSuccessUpdateEmail (#188) — P2 — bugfix-parity — fixed in ccbe67c

  • What WEB does: creates in Drafts with $draft, submits, and moves to Sent via onSuccessUpdateEmail (full mailboxIds replacement, keywords/$draft: null) so the SMTP send happens before the message lands in Sent; needed for servers that encrypt on append (lib/jmap/client.ts:3186-3190, 3231-3238, 3272-3287; changelog "File the post-send message with a full mailboxIds replacement").
  • What RN does: emailCreate.mailboxIds = { [sentMailboxId]: true }, keywords: { $seen: true }, no onSuccessUpdateEmail (src/api/email.ts:786-793, 836-846). With Stalwart encryption-at-rest + encryptOnAppend the copy is encrypted before EmailSubmission/set reads it; and if the submission fails, a never-sent copy sits in Sent.
  • Fix hint: mirror WEB: create in Drafts (needs the drafts mailbox id), onSuccessUpdateEmail: { '#draft': { mailboxIds: {sent: true}, 'keywords/$draft': null } }, and report notUpdated as a filing warning.

• Message-ID / In-Reply-To handling diverges from WEB — P3 — bugfix-parity — fixed in ccbe67c

  • What WEB does: generates messageId client-side from the sender domain, strips angle brackets from inReplyTo/references and sends them as JMAP arrays (lib/jmap/client.ts:546-570, 3177-3180, 3186-3188; changelog "Generate the Message-ID client-side using the sender's domain").
  • What RN does: relies on the server for Message-ID; uses raw header:In-Reply-To:asText / header:References:asText strings (src/api/email.ts:823-826).
  • Fix hint: port generateMessageId + stripMessageIdBrackets, use inReplyTo/references arrays.

• Dead duplicate src/api/submission.ts with zero error checking — P3 — rn-only-bug — fixed in 42ab246

  • What RN does: submission.ts:140-199 is an older sendEmail that ignores notCreated/errors; no importers (grep api/submission empty). Risk is someone wiring it back in.
  • Fix hint: delete the file.

• No keep-alive ping / connection-lost signalling / session refresh — P2 — missing — fixed in edc26ce

  • What WEB does: Core/echo every 30 s with exponential skip back-off, reconnect() on failure, onConnectionChange drives the "connection lost" banner and per-account isConnected (lib/jmap/client.ts:1010-1075; stores/auth-store.ts:199-206); basic-auth 401 re-fetches the session and re-prompts TOTP (client.ts:862-897).
  • What RN does: no ping (grep Core/echo src empty); connectivity comes only from NetInfo (src/stores/network-store.ts), so a reachable-but-down server never surfaces, and the session document (capabilities, shared accounts, eventSourceUrl) is never re-fetched until restart. A basic-auth 401 throws AuthenticationError straight away (src/api/jmap-client.ts:432-434).
  • Fix hint: add a 30 s Core/echo while foregrounded (see AppState finding) feeding network-store.online/account-store.isConnected; on 401 for basic auth re-fetch the session once before failing.

• Password change leaves the stored credential stale, then evicts the account — P1 — rn-only-bug — fixed in 032732c

  • What WEB does: (same class of exposure via cookie, but the server-side passthrough re-reads; out of scope). stores/account-security-store.ts:503-526.
  • What RN does: changePassword succeeds (src/api/account-security.ts:185-197, src/components/settings/AccountSecuritySettings.tsx:137-141) but JMAPClient.credentials.password and the SecureStore entry keep the old password. The next request gets 401 -> AuthenticationError; on the next launch restoreSession clears credentials and removes the account (src/stores/auth-store.ts:516-523), and retrySession does the same (571-587). Push background task also starts failing.
  • Fix hint: add jmapClient.updatePassword(newPassword) that rewrites credentials and persists via setStoredCredentials; call it after a successful changePassword (and after TOTP enable/disable if the password format changes).

• First-touch serialisation for Calendar/Contacts (#907) — P3 — bugfix-parity — fixed in 0b1c240

  • What WEB does: FirstTouchGate holds later Calendar*/AddressBook*/ContactCard* requests per account until the first one settles, so clustered Stalwart doesn't create two default calendars (lib/jmap/first-touch-gate.ts, lib/jmap/client.ts:1121-1128).
  • What RN does: refetchFeatureStores fires fetchContacts, fetchCalendars, refresh concurrently on every login/restore/switch (src/stores/auth-store.ts:81-99).
  • Fix hint: port first-touch-gate.ts and wrap request(); reset it in reset()/loadAccount.

• Mailbox fetch not retried on first login (lazy provisioning, #217) — P3 — bugfix-parity — fixed in 3194b5e

  • What WEB does: retries the initial mailbox fetch when a freshly created account returns no folders (changelog 1.6.x "Retry mailbox fetch on first login to handle lazy provisioning (#217)").
  • What RN does: fetchMailboxes does one Mailbox/get; an empty list on a brand-new Stalwart account stays empty until pull-to-refresh (src/stores/email-store.ts:584-588).
  • Fix hint: if the list is empty and there is no inbox role, retry after ~1 s up to 3 times.

• Session redirect with dropped Authorization not handled — P3 — partial — fixed in 0b1c240

  • What WEB does: detects response.redirected + empty accounts/username and refetches the final URL with the header (lib/jmap/client.ts:911-925).
  • What RN does: fetchSession accepts whatever comes back; resolveAccountId then throws "No account found in JMAP session" (src/api/jmap-client.ts:363-401). iOS strips Authorization on cross-origin redirects.
  • Fix hint: same detection; retry against response.url.

Live updates (SSE / polling / state changes)

• No AppState handling: SSE never paused in background nor recovered on foreground; no refresh on resume — P1 — missing — fixed in edc26ce

  • What WEB does: visibilitychange -> immediate checkForStateChanges() + recycleStaleSSE(); online -> reconnect SSE or poll; polls pause while hidden; 90 s ping-timeout monitor (lib/jmap/client.ts:7332-7400, 6992-6996; changelog #702/#781 notes).
  • What RN does: grep -rn AppState src App.tsx is empty. The EventSource is opened once (App.tsx:380-418, src/api/push.ts:120-157). react-native-sse re-polls only when the XHR reaches DONE with a status (node_modules/react-native-sse/src/EventSource.js:118-131); on onerror/status 0 (socket dropped, iOS suspension, Wi-Fi to cellular) nothing schedules a reconnect (137-149). Result: after the first network blip, push is dead for the rest of the process lifetime with no visible sign; the app also keeps the socket (and 30 s server pings) alive while backgrounded.
  • Fix hint: AppState.addEventListener('change'): on background close the EventSource; on active recreate it and call fetchMailboxes()/refreshEmails()/outbox flush(); also subscribe to useNetworkStore online transitions to recreate. Listen for the SSE error event and schedule a reconnect with back-off.

• SSE Authorization header captured once; stale after OAuth token refresh — P1 — rn-only-bug — fixed in edc26ce

  • What WEB does: authenticatedFetch reads this.authHeader on every (re)connect, and onTokenRefresh retries a 401 SSE connect (lib/jmap/client.ts:7049-7053, 855-863).
  • What RN does: connectEventSource passes { headers: { Authorization: jmapClient.authHeader } } at construction (src/api/push.ts:136-138); react-native-sse reuses this.headers on every reconnect (EventSource.js:83-87). After the access token expires (ensureFreshToken rotates it for normal requests) every SSE reconnect sends the old Bearer -> 401 -> error -> re-poll every 5 s forever (battery drain, server log spam, no push).
  • Fix hint: on error with xhrStatus === 401 close and recreate with the current authHeader; better, recreate the EventSource whenever persistRefreshedTokens runs.

• Push effect keyed on the singleton client: SSE stays bound to the previous account after switchAccount — P1 — rn-only-bug — fixed in edc26ce

  • What WEB does: per-account clients; the push effect depends on activeAccountId and the connected-accounts signature, tearing down and re-creating streams on switch (components/mail/mail-app.tsx:1220-1263).
  • What RN does: the effect deps are [client, isAuthenticated] (App.tsx:418); client is always the same jmapClient object (src/stores/auth-store.ts:155), and isAuthenticated stays true across switchAccount (auth-store.ts:360-432), so the effect never re-runs. The open EventSource keeps the old account's eventSourceUrl + credentials; its events are then dropped by jmapClientServesActiveAccount (src/stores/email-store.ts:986), and the new account gets no live updates until logout/login. The FCM setup effect already includes activeAccountId (App.tsx:378).
  • Fix hint: add activeAccountId (and haveLiveSession) to the push effect deps.

• No SSE failure/fallback path (server 4xx/5xx, proxy without SSE, client cert) — P2 — partial — fixed in edc26ce

  • What WEB does: non-OK SSE response -> fallbackToPolling; stream end -> reconnect after 3 s (rate-limit aware); closeafter/ping template substitution (lib/jmap/client.ts:7049-7066, 7129-7155).
  • What RN does: startPolling is used only when eventSourceUrl is absent (src/api/push.ts:228-230); no error/open listeners on the EventSource. A user with a TLS client certificate (native issue #3) is worst hit: react-native-sse is XHR-based and cannot present the KeyChain cert (src/lib/client-cert.ts:40-43 explains why fetchSecure exists), so the SSE handshake is rejected and no polling starts -> no live updates at all.
  • Fix hint: in connectEventSource, if await getClientCertAlias() is non-null skip SSE and return startPolling(...); add an error handler that, after N consecutive non-401 failures, closes the source and falls back to polling.

• StateChange coverage: EmailSubmission, SieveScript, Identity, VacationResponse, FileNode ignored — P2 — partial — fixed in a071d05 (Sieve/vacation refetch; EmailSubmission/FileNode via state-change-bus)

  • What WEB does: handles Email, EmailSubmission (scheduled list/metadata), Mailbox (any account), Calendar/CalendarEvent (+tasks), SieveScript (filters) (stores/email-store.ts:3242-3310).
  • What RN does: Email/EmailDelivery/Mailbox (src/stores/email-store.ts:981-1020), AddressBook/ContactCard/Contact (src/stores/contacts-store.ts:152-168), Calendar/CalendarEvent incl. shared accounts (src/stores/calendar-store.ts:261-283). ScheduledScreen, filter-store, vacation-store, Files and Identity never refresh on push (grep handleStateChange src/stores/filter-store.ts src/stores/vacation-store.ts empty).
  • Fix hint: add EmailSubmission -> scheduled list refresh (when the Scheduled screen is mounted), SieveScript -> filter-store.fetch, VacationResponse -> vacation store, FileNode -> Files screen refresh; dispatch from the onStateChange fan-out in App.tsx:391-396.

• Contacts state changes ignore shared/group accounts — P3 — partial

  • What WEB does: per-account clients; handleStateChange reacts to the client's own account (stores/email-store.ts:3255-3257); calendar/contacts stores use the account of the shared collection.
  • What RN does: contacts-store.handleStateChange only reads change.changed[jmapClient.accountId] (src/stores/contacts-store.ts:154-156) although address books from shared accounts are shown; calendar-store already folds shared accounts in (calendar-store.ts:263-272).
  • Fix hint: mirror the calendar store's known set using addressBook.accountId.

• Polling fallback is coarse: primary account only, fixed 5 s, no in-flight coalescing, no pause in background — P3 — partial — fixed in edc26ce

  • What WEB does: polls every session account plus Calendar/CalendarEvent/SieveScript, 3 s active / 20 s slow, skips when document.hidden, coalesces overlapping polls (#781) (lib/jmap/client.ts:6948-6954, 7157-7301).
  • What RN does: startPolling polls Mailbox/get + Email/get for the primary account every 5 s with setInterval, no in-flight guard, never paused (src/api/push.ts:163-202); shared accounts, calendar, contacts and sieve never change under polling.
  • Fix hint: reuse the WEB request shape (mbx:<id>/eml:<id> call ids), add an in-flight flag and AppState pause, 20 s cadence in fallback.

• SSE stream keeps the whole response in memory; no periodic recycle — P3 — rn-only-bug — fixed in edc26ce

  • What WEB does: reads the body as a stream and discards processed chunks; recycles a silent stream after 90 s (lib/jmap/client.ts:7070-7105, 7332-7373).
  • What RN does: react-native-sse accumulates xhr.responseText for the life of the connection (EventSource.js:108, _lastIndexProcessed), and RN requests {ping}=30, {closeafter}=no (src/api/push.ts:126-129), so memory grows for every ping/event until reconnect. No ping-timeout detection either.
  • Fix hint: either request closeafter=state (server closes after each event; library auto-reconnects) or recycle the EventSource every ~30 min / when no ping event arrived in 90 s (add a ping listener).

• Push subscription types include Email and Mailbox; no emailPush spam filter — P2 — partial — fixed in 00faceb

  • What WEB does: subscribes to EmailDelivery only, plus an emailPush filter excluding $junk/Junk when the server advertises urn:ietf:params:jmap:emailpush (lib/web-push.ts:39-52, lib/jmap/client.ts:8085-8142; changelog 1.9.x "Stop sending notifications for spam").
  • What RN does: PUSH_TYPES = ['Email', 'EmailDelivery', 'Mailbox'] (src/lib/push-notifications.ts:104); createPushSubscription has no emailPush support (src/api/push.ts:23-57). Every read/flag/move on any device wakes the relay -> FCM -> headless task, which then re-queries the inbox (src/lib/push-background-task.ts:452-455); a spam delivery still triggers a push (only the inbox notKeyword $seen query hides it, at the cost of a wake-up).
  • Fix hint: subscribe to EmailDelivery only; add hasEmailPushCapability() + emailPush filter as in WEB; the relay must forward it (see memory note: relay lacks EmailPush).

• Headless push task re-binds the singleton client while the UI may be running — fixed in 1f2df5f — P2 — rn-only-bug

  • What WEB does: N/A (service worker has its own fetch path).
  • What RN does: processAccountForPush calls jmapClient.loadAccount(accountId) for each candidate account (src/lib/push-background-task.ts:445) and the finally re-loads the active one (438-440, errors swallowed). HeadlessJS tasks run inside the live RN instance when the app is foregrounded, so UI requests issued during that window are sent with another account's credentials/session, and a failing final loadAccount leaves session = null (jmap-client.ts:269-270) until the next network event.
  • Fix hint: use a detached fetch path like src/api/unified-inbox.ts:116-131 (credentials read from SecureStore, own apiUrl) instead of mutating the singleton.

Offline cache & outbox

• Outbox retries forever on errors that look transient but are permanent — P2 — rn-only-bug — fixed in 0205aa0

  • What RN does: isTransientNetworkError treats any TypeError and messages containing session expired/not connected as transient (src/lib/network-error.ts:48-63). (a) A JMAP method error makes the unchecked read path throw TypeError: Cannot read property 'list' of undefined (see method-error finding) -> transient -> recordError(..., false) never increments attempts (src/stores/outbox-store.ts:203-206, 243-254) -> the queue is wedged on that entry until reinstall. (b) AuthenticationError('Session expired') from a revoked password is also transient -> same wedge. WEB has no outbox (N/A) but never mis-classifies auth errors as transient.
  • Fix hint: classify by error class (NetworkError, RequestTimeoutError, RateLimitError) not by TypeError/message; treat AuthenticationError as terminal and pause the queue.

• Permanently failed outbox ops are dropped silently; optimistic state never reverted — P2 — rn-only-bug — fixed in 0205aa0

  • What RN does: after 5 attempts the entry is removed with console.warn (src/stores/outbox-store.ts:210-216); the list/cache was already patched optimistically (offline-cache-store.patch, email-store mutations) and nothing refetches, so the UI shows a move/flag the server rejected until the next full refresh; OfflineBanner only shows the count.
  • Fix hint: keep a failed: OutboxEntry[] in the store, surface it in OfflineBanner/AboutDataSettings, and trigger refreshEmails() for the affected mailbox when an op is dropped.

• Interrupted flush is not resumed until the next online transition or launch — P3 — rn-only-bug — fixed in 0205aa0

  • What RN does: flush() breaks on the first transient error (src/stores/outbox-store.ts:203-206); the only triggers are haveLiveSession and NetInfo online flips (App.tsx:289-295). A blip that NetInfo never reports (server hiccup) leaves the queue idle.
  • Fix hint: schedule a retry with back-off after a transient break; also flush on AppState active.

• Offline onlineRun fallback silently changes semantics (archive auto-foldering) — P3 — rn-only-bug — fixed in 0205aa0

  • What RN does: applyOrQueueBatch runs the richer onlineRun (e.g. year/month archive foldering) and on transient failure re-queues the plain mailboxes primitives (src/stores/outbox-store.ts:279-292), so the replay lands in the top-level Archive without the year/month folder the user configured.
  • Fix hint: encode the folder creation into the queued op (or queue an archive op kind that re-runs the foldering logic on replay).

• Email/changes.hasMoreChanges ignored in the incremental refresh — P3 — partial — fixed in f07e039

  • What WEB does: WEB refetches the page instead of diffing, so it is not exposed.
  • What RN does: getEmailChanges returns hasMoreChanges (src/api/email.ts:355-376) but refreshEmails uses updated/destroyed once (src/stores/email-store.ts:836-846); after a long offline gap the truncated lists leave stale keywords on some rows until the snapshot is invalidated. (The mailbox path does drain, email-store.ts:575-579, 601.)
  • Fix hint: loop while hasMoreChanges, or drop the snapshot and fall back to the full re-query when it is set.

• Offline cache + outbox land in Android auto-backup — P2 — missing (security) — fixed in 7f9f5af

  • What WEB does: N/A (no persistent mail cache).
  • What RN does: android:allowBackup="true" with @xml/secure_store_backup_rules from the expo-secure-store plugin, which only excludes SecureStore's own prefs (android/app/src/main/AndroidManifest.xml:16); the AsyncStorage SQLite DB (full cached bodies webmail:offline-cache:entry:v2:*, outbox, settings, account registry) is backed up to the user's Google account.
  • Fix hint: add an app-owned fullBackupContent/dataExtractionRules excluding databases/RKStorage (AsyncStorage) or set allowBackup=false via an Expo config plugin.

• Send has no offline path and no draft fallback — P2 — missing

  • What WEB does: no offline queue either, but send failures leave the composer open with the draft autosaved (composer agent's area); send itself has a deadline (#702).
  • What RN does: ComposeScreen shows Alert('Send failed') and keeps the modal (src/screens/ComposeScreen.tsx:975-979); there is no draft API in src/api/email.ts (grep -n '[Dd]raft' src/api/email.ts only finds the send create id), so the body is lost if the user leaves, and an offline send is not queued although the outbox exists.
  • Fix hint: either add an outbox send op kind (blob uploads must already be done) or at minimum persist the composer state locally on failure.

Security hardening (RN)

• Linking.openURL with unvalidated URIs from server data (contacts, calendar invitations) — P2 — rn-only-bug — fixed in 96272b6 (contacts 63bf392, calendar/invitation links confirm the host)

  • What WEB does: links are sanitized in the viewer; iCal/vCard URLs open via anchor with rel=noopener (viewer agent's area); isValidUnsubscribeUrl gates unsubscribe links (components/email/unsubscribe-banner.tsx:63).
  • What RN does: openUrl(uri) on a contact's stored URL (src/screens/ContactDetailScreen.tsx:173-175) and Linking.openURL(videoUri) on virtualLocations[0].uri from an incoming invitation (src/components/calendar/EventDetailSheet.tsx:169, 234; src/components/email/CalendarInvitationBanner.tsx:92, 159) accept any scheme: intent://...#Intent;component=...;end launches arbitrary exported activities on Android, file://, content://, or third-party deep links. EmailBodyView already restricts to https?|mailto|tel|sms (src/components/EmailBodyView.tsx:715-723).
  • Fix hint: a shared openExternalUrl() that allows only https?:, mailto:, tel:, sms: and shows the host in a confirmation for invitation links.

• Password handoff over a custom-scheme redirect (bulwarkmobile://…#password=) is interceptable; OAuth state uses Math.random — P1 — rn-only-bug — fixed in 2c0dbd1 (CSPRNG state + endpoint validation; moving the password out of the fragment is a webmail change)

  • What WEB does: the mobile handoff page redirects with credentials in the fragment (lib/deep-link-handoff.ts, changelog "Mobile handoff page with JMAP authentication verification").
  • What RN does: the password flow returns the clear-text password in the redirect fragment (src/lib/oauth.ts:92-99); the scheme is a plain intent-filter (AndroidManifest.xml:25-30), which any installed app can also register (no App Links verification), so a malicious app can receive the redirect. state is 16 bytes of Math.random (oauth.ts:41-47) - it prevents a forged callback from being accepted only if unpredictable; and the fragment's server_url, token_endpoint, client_id are trusted as-is (oauth.ts:101-121), so a forged callback can point refresh traffic at an attacker host.
  • Fix hint: never send the password in the redirect (mint short-lived tokens or a one-time pairing code like redeemPairingCode, oauth.ts:165-208); generate state with expo-crypto getRandomBytes; validate server_url/token_endpoint are https and the token endpoint host matches the server host.

• http:// server URLs accepted without a warning; cleartext then fails opaquely — P2 — missing — fixed in ce97232

  • What WEB does: warns when the JMAP URL points at a local-only host (changelog "Setup: Warn when the JMAP URL points at a local-only host"); Basic auth travels server-to-server.
  • What RN does: normalizeServerInput accepts http (src/lib/server-discovery.ts:28-30), QR payloads accept http (src/lib/oauth.ts:144, 155), connect() never checks the scheme. Android has no usesCleartextTraffic (app.config.js has no android.usesCleartextTraffic; manifest has none) so http fails with "Network request failed" on API 28+, while iOS ATS may or may not allow it, so the user gets an unexplained error - or, worse, Basic credentials in clear on iOS.
  • Fix hint: reject http:// in normalizeServerInput except localhost/RFC-1918 in dev builds, with a clear message.

• Weak randomness for TOTP secret / UUIDs (falls back to Math.random) — P2 — rn-only-bug — fixed in 2c0dbd1

  • What WEB does: server-side otpauth Secret({size:20}) from Node crypto; generateUUID() guarded (changelog "Replace unguarded crypto.randomUUID() with safe generateUUID()").
  • What RN does: randomBytes tries crypto.getRandomValues, then crypto.randomUUID, then Math.random (src/lib/totp.ts:404-437). expo-crypto is not a dependency (package.json), Hermes exposes no crypto global by default, so a long-lived 2FA secret is minted from Math.random; the same fallback is documented for lib/uuid.ts and lib/oauth.ts.
  • Fix hint: add expo-crypto and use Crypto.getRandomBytes(20) / Crypto.randomUUID(); remove the Math.random branches.

• Client-cert native fetch follows redirects with Authorization and turns POST into GET (#627 class) — P3 — bugfix-parity — fixed in 6f747db

  • What WEB does: postJmap follows redirects manually, keeps POST, only to the same host or an https upgrade (lib/stalwart/jmap-api.ts:44-93).
  • What RN does: instanceFollowRedirects = true on HttpURLConnection (android/app/src/main/java/com/anonymous/bulwarkmobile/BulwarkClientCertModule.kt:144); a 301 in front of /jmap/ re-issues as GET (Stalwart answers 404 problem+json) and cross-host redirects re-send the header. The non-cert fetch path has the same POST->GET behaviour but that matches browser semantics WEB also lives with client-side.
  • Fix hint: instanceFollowRedirects = false, return the 3xx to JS, and handle the redirect in secureFetch with the same host/https-upgrade rule.

• Client-cert path buffers whole bodies through base64 over the bridge with a 30 s cap — P3 — rn-only-bug — fixed in 6f747db (blob deadline raised to 300 s; streaming still deferred)

  • What RN does: the whole response is read into memory and base64-encoded (BulwarkClientCertModule.kt:170-190, src/lib/client-cert.ts:204-216); attachment downloads for cert users go through secureFetch(...).arrayBuffer() (src/lib/email-export.ts:100-110) and uploads through bodyToBase64 (client-cert.ts:171-188), so a 50 MB attachment costs ~200 MB of JS heap and can time out at 30 s (client-cert.ts:250; WEB uses 300 s for transfers, lib/jmap/client.ts:634).
  • Fix hint: stream to a file in the native module (FileOutputStream) and return the path; raise the transfer timeout.

• Blob downloads via File.downloadFileAsync bypass token refresh — P2 — rn-only-bug — fixed in d2ed27f

  • What WEB does: fetchBlob goes through authenticatedFetch, which refreshes a Bearer token on 401 (lib/jmap/client.ts:4150-4157, 855-863).
  • What RN does: downloadInto builds the header from jmapClient.authHeader without ensureFreshToken() and does not retry on 401 (src/lib/email-export.ts:93-97); after the access token expires, attachment/EML download fails until some other JMAP call has refreshed the token. fetchBlobArrayBuffer does refresh (src/api/jmap-client.ts:575-581).
  • Fix hint: expose ensureFreshToken() publicly, call it before downloadFileAsync, and on 401 call forceRefreshToken() and retry once.

• Downloaded attachment temp files are never cleaned up — P3 — rn-only-bug — fixed in d2ed27f (launch sweep wired in App.tsx)

  • What RN does: shareAttachment/openAttachment write into Paths.cache (src/lib/email-export.ts:127, 195) and only delete when the same name is reused; the APK installer deletes on failure (src/lib/install-update.ts:78, 143). Cache may be purged by the OS but shared files linger (readable to apps that were granted the URI).
  • Fix hint: delete the file after the share sheet resolves, and sweep Paths.cache older than a day at launch.

• WebView: data: navigations allowed inside the message frame — P3 — partial — fixed in 06742ef

  • What WEB does: message HTML is sandboxed in an srcDoc iframe with a CSP meta tag (changelog 1.5.x); data: top-level navigation is blocked by the browser.
  • What RN does: onShouldStartLoadWithRequest returns true for any data: URL (src/components/EmailBodyView.tsx:715-718), so <a href="data:text/html,..."> replaces the message with attacker HTML rendered inside the app chrome (phishing form); the WebView is otherwise well hardened (originWhitelist=['about:blank'], file access off, mixedContentMode="never", setSupportMultipleWindows={false}, incognito, domStorageEnabled={false}, EmailBodyView.tsx:675-712).
  • Fix hint: allow data: only for request.isTopFrame === false or block it entirely (the body is loaded via source={{html}}, not a data: URL).

• No screenshot / recent-apps protection option — P3 — missing

  • What WEB does: N/A.
  • What RN does: no FLAG_SECURE/expo-screen-capture anywhere; mail content appears in the Android recents thumbnail.
  • Fix hint: optional "Hide content in app switcher" setting using expo-screen-capture preventScreenCaptureAsync.

• Sender/subject of every FCM message logged to logcat — fixed in 00faceb — P3 — rn-only-bug

  • What RN does: console.log('[push] fcm message', payload.title) in production (App.tsx:301-303). No credential logging found (grep for password/token/secret in console calls is empty).
  • Fix hint: drop or guard with __DEV__.

• Custom SHA-256 implementation (verified correct) could use expo-crypto — P3 — rn-only-bug — fixed in n/a (kept: PKCE needs a synchronous digest; expo-crypto digest is async)

  • What RN does: src/lib/sha256.ts is a straight FIPS 180-4 implementation (padding, 64-bit length split, unsigned hex output all correct) used only for APK checksum verification (src/lib/install-update.ts:118-127); verification is opt-in when the release body carries a hash.
  • Fix hint: once expo-crypto is added (see randomness finding) replace with Crypto.digest('SHA-256', bytes); keep the size check.

• TOTP helper: RFC 6238 compatible; issuer hard-coded — P3 — partial — fixed in ce97232

  • What WEB does: server-verified via x:AccountPassword/set otpAuth.otpCode; enrolment via otpauth with the app/brand as issuer.
  • What RN does: generateTotpEnrolment produces otpauth://totp/Stalwart:<label>?secret=…&algorithm=SHA1&digits=6&period=30 (src/lib/totp.ts:469-485) - correct parameters, base32 without padding correct; verification is server-side (comment totp.ts:391-396). Issuer Stalwart instead of the server host/brand.
  • Fix hint: use the server hostname (or configured brand) as issuer.

• Relay base URL stored unvalidated (http allowed) — P3 — rn-only-bug — fixed in f6f26f7

  • What RN does: setStoredRelayBaseUrl only trims slashes (src/lib/push-notifications.ts:170-176); the relay receives the FCM token and the JMAP push-subscription URL slot. WEB's telemetry/push endpoints are validated server-side against internal hosts (changelog "Block telemetry endpoint from pointing at internal/loopback hosts").
  • Fix hint: require https:// in the settings input.

Stalwart admin/self-service, S/MIME, encryption at rest

• Encryption at rest is read-only; no public-key management — fixed in ddae1e6 — P2 — partial — fixed in 69bedf0 (API; settings UI with the settings agent)

  • What WEB does: fetchCryptoInfo/updateEncryptionAtRest with @type (Disabled|Aes128|Aes256), publicKey, encryptOnAppend, allowSpamTraining (spam training before encryption) and x:PublicKey/query|get|set CRUD with emailAddresses/expiresAt (stores/account-security-store.ts:355-448, 625-700; changelog 1.7.x "Manage S/MIME and PGP public keys and configure Stalwart encryption at rest", 1.9.x "Per-account isolation for encryption at rest").
  • What RN does: fetchEncryptionType returns only the @type (src/api/account-security.ts:150-155); shown read-only in AccountSecuritySettings.tsx:595. No x:PublicKey/*, no set path. Per-account isolation is inherent (single-session client uses jmapClient.accountId).
  • Fix hint: port updateEncryptionAtRest, fetchPublicKeys, createPublicKey, removePublicKey into account-security.ts (same STALWART_USING) and a key list/paste screen.

• S/MIME settings screen is a mock; no S/MIME detection in the viewer — P2 — missing — fixed in 06742ef (viewer banner; settings stub hidden in 3d0d440; crypto deferred)

  • What WEB does: built-in S/MIME was removed from core into the privileged crypto plugin (changelog 1.5.0 note, "S/MIME: The built-in S/MIME implementation has been removed from core"); core keeps only detection (isSmimeEmail, lib/jmap/client.ts:484-505), the range-limited blob read for signature checks (7503-7550), and the plugin hook surface. Per-account key isolation, legacy 3DES/PBE and self-signed detection live in the plugin.
  • What RN does: SmimeSettings renders MOCK_KEYS/MOCK_CERTS and three settings that nothing reads (src/components/settings/SmimeSettings.tsx:32-61; src/stores/settings-store.ts:203-205, 308-310), reachable from Settings as encryption (src/screens/SettingsScreen.tsx:130). Nothing detects application/pkcs7-mime/multipart/signed bodies, so an encrypted message shows as an empty body with a smime.p7m attachment.
  • Fix hint: parity for RN core = (1) port isSmimeEmail and show a "signed/encrypted with S/MIME - not supported on mobile" banner, (2) remove or hide the mock section. Full sign/verify/decrypt needs WebCrypto, which Hermes lacks: it would require react-native-quick-crypto (OpenSSL) plus a PKCS#7/CMS parser (pkijs runs on WebCrypto and would need a shim), private keys in SecureStore/Keychain, and per-account isolation of the key store; there is no plugin tier in RN to host it. Treat as a separate project.

• Display name not refreshed from the Stalwart principal on login/restore/switch (#900) — P3 — bugfix-parity — fixed in b52768e

  • What WEB does: refreshes the account label from x:Account/get on login, restore and switch (changelog 1.9.x "#900"; memory note: principal name is copied into the Identity only once).
  • What RN does: fetchPrincipal exists (src/api/account-security.ts:157-181) but is only called from the security screen (AccountSecuritySettings.tsx:595); addAccount uses displayName: username (src/stores/auth-store.ts:187-195, 123-131).
  • Fix hint: call fetchPrincipal() (guarded by isStalwartSupported()) after applyConnectedState and updateAccount({displayName}).

• Native issue #47 "Account security not accessible" - likely gating — P3 — rn-only-bug (unverified) — fixed in 032732c

  • What RN does: the screen hides password/TOTP for Bearer sessions (src/api/jmap-client.ts:66-68) and shows "not available" when urn:stalwart:jmap is absent (src/api/account-security.ts:51-55); an OAuth handoff login therefore has no password management even on Stalwart. WEB shows the same sections for OAuth users via the passthrough with stored basic credentials.
  • Fix hint: confirm against the issue; consider allowing app-password/API-key management for Bearer sessions (they only need x:* methods, not the password).

Newsletter unsubscribe

• List-Unsubscribe not parsed or offered — P2 — missing — fixed in d2ed27f
  • What WEB does: extractListHeaders parses List-Unsubscribe/List-Id/List-Help/List-Post (lib/email-headers.ts:253-300); the banner opens http links in a new tab (no RFC 8058 one-click POST) and sends mailto: unsubscribes itself via JMAP (components/email/unsubscribe-banner.tsx:63-110; changelog 1.5.x "Send mailto: unsubscribe ourselves instead of via the OS handler").
  • What RN does: EMAIL_FULL_PROPERTIES requests no headers (src/api/email.ts:11-15); no parsing, no banner (grep -rln unsubscribe src hits only unrelated store code).
  • Fix hint: add header:List-Unsubscribe:asText and header:List-Unsubscribe-Post:asText to the full properties; port parseUnsubscribeUrls; for http+List-Unsubscribe=One-Click do the RFC 8058 POST (application/x-www-form-urlencoded, body List-Unsubscribe=One-Click) in-app, otherwise open the link; for mailto: reuse sendEmail.

Misc network

• Unified inbox detached fetch: no timeout, no 429/maxConcurrentRequests handling, N parallel sessions — P3 — partial — fixed in 6ae21d5
  • What WEB does: per-account clients share the retry/timeout/rate-limit pipeline; unified fetch errors are collected per account (stores/email-store.ts:3325-3345).
  • What RN does: jmapPost/fetchInboxForAccount do a bare secureFetch per account and per shared account in parallel (src/api/unified-inbox.ts:116-131, 215-233), swallowing shared-account errors and only mapping 401 to "Session expired".
  • Fix hint: route through the same request() helper once it has deadlines/back-off (pass explicit credentials instead of the singleton).

Verified at parity (brief list, so the fixer knows what NOT to redo)

• Session discovery, primaryAccounts selection (mail -> core -> first account), shared/group account detection (src/api/jmap-client.ts:388-401, 480-493 vs lib/jmap/client.ts:988-995, 4421-4463).
• Per-capability account ids for Sieve and Files (src/api/sieve.ts:20-23, src/api/files.ts:27-31); calendar/contacts use the primary account on both sides in practice.
• OAuth proactive refresh with 60 s leeway, reactive refresh on 401, single-flight refresh promise, refresh-token rotation fallback (src/api/jmap-client.ts:193-221, src/lib/oauth.ts:210-265).
• Blob download/upload URL templating with encodeURIComponent and RN-safe string splitting (no new URL()), shared-account accountId override (src/api/jmap-client.ts:557-566, src/api/blob.ts).
• Upload response parsing accepts both {blobId} and {[accountId]: {blobId}} shapes (src/api/blob.ts:38-61).
• Mailbox/changes incremental sync with hasMoreChanges drain and cannotCalculateChanges fallback; folder tree kept on failure (#780 behaviour) (src/stores/email-store.ts:528-612).
• Email/queryChanges + Email/changes incremental list refresh with snapshot guard (issue #10) and full re-query fallback (src/stores/email-store.ts:770-980).
• null for patch removal, false stripped from mailboxIds maps (src/api/email.ts:456, 551-556).
• FilterOperator/FilterCondition kept separate in query filters (src/api/email.ts:225-237).
• getSharedMailboxes chunks to maxCallsInRequest (src/api/email.ts:84-105); getEvents/getContacts/fetchEmailsChunked/offline sync chunk to maxObjectsInGet.
• Send: /error, notCreated checked; HOLDFOR envelope for scheduled send; FUTURERELEASE capability check (src/api/email.ts:836-873, src/api/jmap-client.ts:505-531).
• Push subscription create/verify/update/destroy with using: [core] and 90-day expiry refresh (src/api/push.ts:9-114, src/lib/push-notifications.ts).
• Outbox: idempotent full-state ops, per-account buckets, destroy-wins coalescing, oldest-first replay, account-switch guards (src/stores/outbox-store.ts).
• Offline cache: per-account buckets, index + entry keys, eviction by receivedAt, optimistic patch, abort on account switch (src/stores/offline-cache-store.ts); getEmailDetail cache fallback.
• Credentials in expo-secure-store (never AsyncStorage); SecureStore key sanitising; per-account keys; legacy migration.
• Client-cert module uses the platform default X509TrustManager (no trust-all) (BulwarkClientCertModule.kt:216-222).
• WebView hardening: originWhitelist=['about:blank'], no file/universal access, mixedContentMode="never", no multiple windows, no cookies/DOM storage, incognito, external links limited to https?|mailto|tel|sms (src/components/EmailBodyView.tsx:675-724).
• No secrets in console.* output; usesNonExemptEncryption: false declared (app.config.js:370).
• Stalwart self-service via urn:stalwart:jmap: password change, display name, TOTP enable/disable, app passwords and API keys with IP allow-list, principal read (src/api/account-security.ts), with proper error/notUpdated checks.
• SHA-256 implementation correct (FIPS 180-4) and APK size + optional checksum verification (src/lib/sha256.ts, src/lib/install-update.ts:100-127).

N/A on mobile

• Server-side SSRF/DNS-rebinding guard, endpoint allow-list, OAUTH_ALLOW_PRIVATE_ENDPOINTS, IPv6 transition-address checks (lib/security/url-guard.ts, lib/stalwart/server-fetch.ts; GHSA-24w9): RN talks to the server directly from the device; the only analogue is scheme validation (covered above).
• CSP frame-src/connect-src/object-src changes, srcDoc iframe sandbox, plugin bundle signing, admin dashboard, setup wizard, SESSION_SECRET, session-cookie slots, Stalwart JMAP passthrough (#627) and auth-context binding: RN has no proxy tier; it holds credentials itself and calls x:* methods directly.
• MAX_SSE_STREAMS/per-tab socket budget (#702), "one SSE stream per client", browser visibilitychange/online events, document.hidden poll pausing: RN is single-session; the equivalent concern is AppState (listed as a gap).
• Service-worker PWA caching, blob: object URLs, URL.revokeObjectURL, window.open for unsubscribe links.
• WEB S/MIME plugin (privileged same-origin plugin tier), onBeforeBlobUpload offload hooks, plugin crypto API: no plugin system in RN.
• x-www-form-urlencoded TOTP token exchange on the WEB server (/api/auth/totp): RN verifies TOTP through Stalwart's otpCode directly.