diff --git a/frontend/src/lib/components/DisplayResult.svelte b/frontend/src/lib/components/DisplayResult.svelte
index ff4196443d..8ac06662d8 100644
--- a/frontend/src/lib/components/DisplayResult.svelte
+++ b/frontend/src/lib/components/DisplayResult.svelte
@@ -187,11 +187,6 @@
 			: `data:text/json;charset=utf-8,${encodeURIComponent(toJsonStr(result))}`
 	)
 	let resultDownloadName = $derived(`${filename ?? 'result'}.json`)
-	async function onResultDownload(e: MouseEvent) {
-		if (!resultApiPath || !shouldDownloadViaClient()) return
-		e.preventDefault()
-		await downloadViaClient(resultApiPath, resultDownloadName)
-	}
 
 	function checkIfS3(result: any, keys: string[]) {
 		return keys.includes('s3') && typeof result.s3 === 'string'
@@ -1020,13 +1015,17 @@
 					{:else}
 						{#if largeObject}
 							<div class="text-xs text-emphasis"
-								><a
-									download={resultDownloadName}
-									href={resultDownloadHref}
-									onclick={onResultDownload}
-								>
-									Download {filename ? '' : 'as JSON'}
-								</a>
+								>{#if resultApiPath && shouldDownloadViaClient()}
+									<button
+										onclick={() => downloadViaClient(resultApiPath!, resultDownloadName)}
+									>
+										Download {filename ? '' : 'as JSON'}
+									</button>
+								{:else}
+									<a download={resultDownloadName} href={resultDownloadHref}>
+										Download {filename ? '' : 'as JSON'}
+									</a>
+								{/if}
 								{#if download_as_csv}
 									<DownloadCsv
 										getContent={() => convertJsonToCsv(result)}
diff --git a/frontend/src/lib/components/LogViewer.svelte b/frontend/src/lib/components/LogViewer.svelte
index 9d7b71b6e3..39089dec8b 100644
--- a/frontend/src/lib/components/LogViewer.svelte
+++ b/frontend/src/lib/components/LogViewer.svelte
@@ -208,11 +208,6 @@
 	let logsApiPath = $derived(`/w/${$workspaceStore}/jobs_u/get_logs/${jobId}`)
 	let downloadHref = $derived(withExternalDomain(`${base}/api${logsApiPath}`))
 	let downloadName = $derived(`windmill_logs_${jobId}.txt`)
-	async function onDownloadClick(e: MouseEvent) {
-		if (!shouldDownloadViaClient()) return
-		e.preventDefault()
-		await downloadViaClient(logsApiPath, downloadName)
-	}
 	let truncatedContent = $derived(truncateContent(content, loadedFromObjectStore, LOG_LIMIT))
 	let prefixInfo = $derived(findPrefixInfo(truncatedContent))
 	let downloadStartUrl = $derived(findStartUrl(truncatedContent, prefixInfo))
@@ -357,14 +352,21 @@
 				<div class="flex gap-2 justify-end flex-1">
 					{#if jobId && download}
 						<div class="flex items-center">
-							<a
-								class="text-primary pb-0.5"
-								target="_blank"
-								href={downloadHref}
-								download={downloadName}
-								onclick={onDownloadClick}
-								><Download size="14" />
-							</a>
+							{#if shouldDownloadViaClient()}
+								<button
+									class="text-primary pb-0.5"
+									onclick={() => downloadViaClient(logsApiPath, downloadName)}
+									><Download size="14" />
+								</button>
+							{:else}
+								<a
+									class="text-primary pb-0.5"
+									target="_blank"
+									href={downloadHref}
+									download={downloadName}
+									><Download size="14" />
+								</a>
+							{/if}
 						</div>
 					{/if}
 					<button onclick={logViewer.openDrawer}><Expand size="12" /></button>
diff --git a/frontend/src/lib/components/ParqetCsvTableRenderer.svelte b/frontend/src/lib/components/ParqetCsvTableRenderer.svelte
index 91cc107791..fd08eb64be 100644
--- a/frontend/src/lib/components/ParqetCsvTableRenderer.svelte
+++ b/frontend/src/lib/components/ParqetCsvTableRenderer.svelte
@@ -203,16 +203,24 @@
 	{#if !disable_download && !s3resource.endsWith('.csv')}
 		{@const csvApiPath = `/w/${workspaceId}/job_helpers/download_s3_parquet_file_as_csv?file_key=${encodeURIComponent(s3resource)}${storage ? `&storage=${storage}` : ''}`}
 		{@const csvName = (s3resource.split('/').pop() ?? 'download') + '.csv'}
-		<a
-			target="_blank"
-			href="{base}/api{csvApiPath}"
-			class="text-secondary w-full text-right underline text-2xs whitespace-nowrap"
-			onclick={async (e) => {
-				if (!shouldDownloadViaClient()) return
-				e.preventDefault()
-				await downloadViaClient(csvApiPath, csvName)
-			}}><div class="flex flex-row-reverse gap-2 items-center"><Download size={12} /> CSV</div></a
-		>
+		{#if shouldDownloadViaClient()}
+			<button
+				class="text-secondary w-full text-right underline text-2xs whitespace-nowrap"
+				onclick={() => downloadViaClient(csvApiPath, csvName)}
+				><div class="flex flex-row-reverse gap-2 items-center"
+					><Download size={12} /> CSV</div
+				></button
+			>
+		{:else}
+			<a
+				target="_blank"
+				href="{base}/api{csvApiPath}"
+				class="text-secondary w-full text-right underline text-2xs whitespace-nowrap"
+				><div class="flex flex-row-reverse gap-2 items-center"
+					><Download size={12} /> CSV</div
+				></a
+			>
+		{/if}
 	{/if}
 
 	{#if nbRows != undefined}
diff --git a/frontend/src/lib/components/common/fileDownload/FileDownload.svelte b/frontend/src/lib/components/common/fileDownload/FileDownload.svelte
index 0cb48eb7e1..8d6529764b 100644
--- a/frontend/src/lib/components/common/fileDownload/FileDownload.svelte
+++ b/frontend/src/lib/components/common/fileDownload/FileDownload.svelte
@@ -26,26 +26,26 @@
 	)
 	let href = $derived(`${base}/api${apiPath}`)
 
-	async function onclick(e: MouseEvent) {
-		if (!shouldDownloadViaClient()) return
-		e.preventDefault()
-		await downloadViaClient(apiPath, filename)
-	}
+	const sharedClass = `relative center-center flex w-full text-center font-normal text-primary text-sm
+border border-dashed border-gray-400 hover:border-blue-500
+focus-within:border-blue-500 hover:bg-blue-50 dark:hover:bg-frost-900 focus-within:bg-blue-50
+duration-200 rounded-lg p-1 gap-2`
 </script>
 
 {#if s3object && s3object?.s3}
-	<a
-		class="relative center-center flex w-full text-center font-normal text-primary text-sm
-border border-dashed border-gray-400 hover:border-blue-500
-focus-within:border-blue-500 hover:bg-blue-50 dark:hover:bg-frost-900 focus-within:bg-blue-50
-duration-200 rounded-lg p-1 gap-2"
-		{href}
-		download={filename}
-		{onclick}
-	>
-		<Download />
-		<span>
-			{s3object?.storage ? `s3://${s3object.storage}/${s3object.s3}` : `s3:///${s3object.s3}`}
-		</span>
-	</a>
+	{#if shouldDownloadViaClient()}
+		<button class={sharedClass} onclick={() => downloadViaClient(apiPath, filename)}>
+			<Download />
+			<span>
+				{s3object?.storage ? `s3://${s3object.storage}/${s3object.s3}` : `s3:///${s3object.s3}`}
+			</span>
+		</button>
+	{:else}
+		<a class={sharedClass} {href} download={filename}>
+			<Download />
+			<span>
+				{s3object?.storage ? `s3://${s3object.storage}/${s3object.s3}` : `s3:///${s3object.s3}`}
+			</span>
+		</a>
+	{/if}
 {/if}
diff --git a/frontend/src/lib/components/propertyPicker/ObjectViewer.svelte b/frontend/src/lib/components/propertyPicker/ObjectViewer.svelte
index d954618518..9746991d6b 100644
--- a/frontend/src/lib/components/propertyPicker/ObjectViewer.svelte
+++ b/frontend/src/lib/components/propertyPicker/ObjectViewer.svelte
@@ -410,18 +410,26 @@
 						{#if getTypeAsString(jsonFiltered) === 's3object'}
 							{@const s3DownloadApiPath = `/w/${$workspaceStore}/job_helpers/download_s3_file?file_key=${encodeURIComponent(jsonFiltered?.s3 ?? '')}${jsonFiltered?.storage ? `&storage=${jsonFiltered.storage}` : ''}`}
 							{@const s3DownloadName = jsonFiltered?.s3.split('/').pop() ?? 'unnamed_download.file'}
-							<a
-								class="text-secondary underline font-semibold text-2xs whitespace-nowrap ml-1 w-fit"
-								href={`/api${s3DownloadApiPath}`}
-								download={s3DownloadName}
-								onclick={async (e) => {
-									if (!shouldDownloadViaClient()) return
-									e.preventDefault()
-									await downloadViaClient(s3DownloadApiPath, s3DownloadName)
-								}}
-							>
-								<span class="flex items-center gap-1"><Download size={12} />download</span>
-							</a>
+							{#if shouldDownloadViaClient()}
+								<button
+									class="text-secondary underline font-semibold text-2xs whitespace-nowrap ml-1 w-fit"
+									onclick={() => downloadViaClient(s3DownloadApiPath, s3DownloadName)}
+								>
+									<span class="flex items-center gap-1"
+										><Download size={12} />download</span
+									>
+								</button>
+							{:else}
+								<a
+									class="text-secondary underline font-semibold text-2xs whitespace-nowrap ml-1 w-fit"
+									href={`/api${s3DownloadApiPath}`}
+									download={s3DownloadName}
+								>
+									<span class="flex items-center gap-1"
+										><Download size={12} />download</span
+									>
+								</a>
+							{/if}
 							<button
 								class="text-secondary underline text-2xs whitespace-nowrap ml-1"
 								onclick={() => {
diff --git a/frontend/src/lib/utils/downloadFile.ts b/frontend/src/lib/utils/downloadFile.ts
index 40f3d8df12..fe37ee5f2c 100644
--- a/frontend/src/lib/utils/downloadFile.ts
+++ b/frontend/src/lib/utils/downloadFile.ts
@@ -1,32 +1,27 @@
 import { OpenAPI } from '$lib/gen'
+import { getHeaders } from '$lib/gen/core/request'
 import { sendUserToast } from '$lib/toast'
 
-async function resolveToken(): Promise<string | undefined> {
-	const t = OpenAPI.TOKEN
-	if (!t) return undefined
-	return typeof t === 'string' ? t : await t({} as any)
-}
-
 /**
- * When OpenAPI.TOKEN is set we cannot rely on a plain `<a href>` browser navigation
- * because the browser does not attach the Authorization header. In that case fetch
- * the file via the OpenAPI client (which uses OpenAPI.BASE and the Bearer token) and
- * trigger a download from a blob URL. Otherwise let the default link behavior happen.
+ * When OpenAPI is configured to authenticate via headers (TOKEN, basic auth,
+ * or arbitrary HEADERS) we cannot rely on a plain `<a href>` browser
+ * navigation because the browser does not attach those headers. In that case
+ * fetch the file via the OpenAPI client (which carries the configured auth)
+ * and trigger a download from a blob URL. Cookie-only auth still works with
+ * a plain link.
  *
  * `apiPath` should be the path relative to OpenAPI.BASE, starting with `/`
  * (e.g. `/w/foo/job_helpers/download_s3_file?file_key=...`).
  */
 export function shouldDownloadViaClient(): boolean {
-	return Boolean(OpenAPI.TOKEN)
+	return Boolean(OpenAPI.TOKEN || OpenAPI.HEADERS || OpenAPI.USERNAME)
 }
 
 export async function downloadViaClient(apiPath: string, filename: string): Promise<void> {
-	const token = await resolveToken()
 	const url = `${OpenAPI.BASE}${apiPath}`
-	const headers: Record<string, string> = {}
-	if (token) headers['Authorization'] = `Bearer ${token}`
 	let response: Response
 	try {
+		const headers = await getHeaders(OpenAPI, { method: 'GET', url: apiPath })
 		response = await fetch(url, { headers, credentials: OpenAPI.CREDENTIALS })
 	} catch (e) {
 		sendUserToast(`Download failed: ${e}`, true)