diff --git a/.travis.yml b/.travis.yml
index 4081daa..952ce42 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ rust:
 - stable
 - beta
 - nightly
-- 1.13.0
+- 1.15.0
 
 matrix:
   allow_failures:
diff --git a/README.md b/README.md
index 8c2cae6..f4527ed 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ Development version:
 
 ## Install
 
-This library requires rust 1.13 or newer.
+This library requires rust 1.15 or newer.
 To use this library, add the following to your `Cargo.toml`:
 
 ```toml
diff --git a/lettre/Cargo.toml b/lettre/Cargo.toml
index c01ab13..a06d668 100644
--- a/lettre/Cargo.toml
+++ b/lettre/Cargo.toml
@@ -21,6 +21,9 @@ openssl = "^0.9"
 base64 = "^0.6"
 hex = "^0.2"
 rust-crypto = "^0.2"
+serde = "^1.0"
+serde_json = "^1.0"
+serde_derive = "^1.0"
 
 [dev-dependencies]
 env_logger = "^0.4"
diff --git a/lettre/src/file/error.rs b/lettre/src/file/error.rs
index e74f566..ab1b2b0 100644
--- a/lettre/src/file/error.rs
+++ b/lettre/src/file/error.rs
@@ -1,6 +1,7 @@
 //! Error and result type for file transport
 
 use self::Error::*;
+use serde_json;
 use std::error::Error as StdError;
 use std::fmt;
 use std::fmt::{Display, Formatter};
@@ -13,6 +14,8 @@ pub enum Error {
     Client(&'static str),
     /// IO error
     Io(io::Error),
+    /// JSON serialization error
+    JsonSerialization(serde_json::Error),
 }
 
 impl Display for Error {
@@ -26,6 +29,7 @@ impl StdError for Error {
         match *self {
             Client(_) => "an unknown error occured",
             Io(_) => "an I/O error occured",
+            JsonSerialization(_) => "a JSON serialization error occured",
         }
     }
 
@@ -43,6 +47,12 @@ impl From<io::Error> for Error {
     }
 }
 
+impl From<serde_json::Error> for Error {
+    fn from(err: serde_json::Error) -> Error {
+        JsonSerialization(err)
+    }
+}
+
 impl From<&'static str> for Error {
     fn from(string: &'static str) -> Error {
         Client(string)
diff --git a/lettre/src/file/mod.rs b/lettre/src/file/mod.rs
index c11cd82..0780b65 100644
--- a/lettre/src/file/mod.rs
+++ b/lettre/src/file/mod.rs
@@ -35,7 +35,10 @@
 
 use EmailTransport;
 use SendableEmail;
+use SimpleSendableEmail;
 use file::error::FileResult;
+
+use serde_json;
 use std::fs::File;
 use std::io::prelude::*;
 use std::path::{Path, PathBuf};
@@ -64,17 +67,16 @@ impl EmailTransport<FileResult> for FileEmailTransport {
 
         let mut f = try!(File::create(file.as_path()));
 
-        let log_line = format!(
-            "{}: from=<{}> to=<{}>\n",
-            email.message_id(),
-            email.from(),
-            email.to().join("> to=<")
+        let simple_email = SimpleSendableEmail::new(
+            &email.from(),
+            email.to().iter().map(String::as_str).collect(),
+            &email.message_id(),
+            &email.message(),
         );
 
-        try!(f.write_all(log_line.as_bytes()));
-        try!(f.write_all(email.message().as_bytes()));
-
-        info!("{} status=<written>", log_line);
+        try!(f.write_all(
+            serde_json::to_string(&simple_email)?.as_bytes(),
+        ));
 
         Ok(())
     }
diff --git a/lettre/src/lib.rs b/lettre/src/lib.rs
index 7d2c184..8b6a303 100644
--- a/lettre/src/lib.rs
+++ b/lettre/src/lib.rs
@@ -13,6 +13,10 @@ extern crate hex;
 extern crate crypto;
 extern crate bufstream;
 extern crate openssl;
+extern crate serde_json;
+extern crate serde;
+#[macro_use]
+extern crate serde_derive;
 
 pub mod smtp;
 pub mod sendmail;
@@ -40,7 +44,7 @@ pub trait EmailTransport<U> {
 }
 
 /// Minimal email structure
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct SimpleSendableEmail {
     /// To
     to: Vec<String>,
diff --git a/lettre/tests/transport_file.rs b/lettre/tests/transport_file.rs
index 4ff9c76..e7eafc6 100644
--- a/lettre/tests/transport_file.rs
+++ b/lettre/tests/transport_file.rs
@@ -28,11 +28,8 @@ fn file_transport() {
 
     assert_eq!(
         buffer,
-        format!(
-            "{}: from=<user@localhost> to=<root@localhost>\n{}",
-            message_id,
-            email.message()
-        )
+        "{\"to\":[\"root@localhost\"],\"from\":\"user@localhost\",\
+        \"message_id\":\"file_id\",\"message\":\"Hello file\"}"
     );
 
     remove_file(file).unwrap();