JWT support for Scala. Bonus extensions for Play JSON and Json4s
Scala Shell
Latest commit e308bd9 Jan 14, 2017 @pauldijou Update plugins, fix bugs


JWT Scala 0.9.2

Scala support for JSON Web Token (JWT). Supports Java 1.6+, Scala 2.10.x and Scala 2.11.x. Optional helpers for Play Framework, Play JSON, Json4s Native and Json4s Jackson.

Pick the right tool for the right job

JWT Scala is divided in several sub-projects each targeting a specific use-case. Depending on your need, you want to pick the right one.

Name Description Samples Scaladoc
jwt-core Pure Scala Jwt API
jwt-play-json play-json lib JwtJson API
jwt-play Play framework JwtSession API
jwt-json4s-native json4s Native implementation JwtJson4s API
jwt-json4s-jackson json4s Jackson implementation JwtJson4s API
jwt-circe circe lib JwtCirce API
jwt-upickle uPickle lib JwtUpickle API

If you need a previous version of the Scaladoc API, check the bottom of this page

You can also check a standalone Play application using jwt-play and implementating a small REST API with authentication and admin role (include a UI too!).


In the following snippet, replace [name] with the actual name of the project you need. Using Java 1.6 or 1.7? Add -legacy after the name of the project. See below why. Using Play 2.3? Use 0.2.1 version since 0.3.0 and up will target Play 2.4.


libraryDependencies ++= Seq(
  "com.pauldijou" %% "[name]" % "0.9.2"

Example for jwt-play using Java 1.6


libraryDependencies ++= Seq(
  "com.pauldijou" %% "jwt-play-legacy" % "0.9.2"

Play Framework

Starting with JWT Scala 0.10, Play Framework support is dropped until it compiles to Scala 2.12.0


  • "org.bouncycastle" % "bcpkix-jdk15on"
  • "commons-codec" % "commons-codec" (only if Java 1.6 or 1.7)


If you are using String key, please keep in mind that such keys need to be parsed. Rather than implementating a super complex parser, the one in JWT Scala is pretty simple and might not work for all use-cases (especially for ECDSA keys). In such case, consider using SecretKey or PrivateKey or PublicKey directly. It is way better for you. All API support all those types.

Check ECDSA samples for more infos.

Name Description
HMD5 HMAC using MD5 algorithm
HS224 HMAC using SHA-224 algorithm
HS256 HMAC using SHA-256 algorithm
HS384 HMAC using SHA-384 algorithm
HS512 HMAC using SHA-512 algorithm
RS256 RSASSA using SHA-256 algorithm
RS384 RSASSA using SHA-384 algorithm
RS512 RSASSA using SHA-512 algorithm
ES256 ECDSA using SHA-256 algorithm
ES384 ECDSA using SHA-384 algorithm
ES512 ECDSA using SHA-512 algorithm

Which Java?

Actually, all sub-projects have two flavours. One target Java 1.8+, using the new Time API and the new Base64 util. This is the default one. If you are using Java 1.6 or 1.7 (which have both reach end-of-life by the way), you will have to use the "legacy" version of the lib. It's exactly the same (in fact, 99% of the code source is shared) except it's using the old Calendar API and the Base64 util from Apache Commons Codec (introducing one small dependency in this particular use-case).

Security concerns

This lib doesn't want to impose anything, that's why, by default, a JWT claim is totally empty. That said, you should always add an issuedAt attribute to it, probably using claim.issuedNow. The reason is that even HTTPS isn't perfect and having always the same chunk of data transfered can be of a big help to crack it. Generating a slightly different token at each request is way better even if it adds a bit of payload to the response. If you are using a session timeout through the expiration attribute which is extended at each request, that's fine too. I can't find the article I read about that vulnerability but if someone has some resources about the topic, I would be glad to link them.

Got a problem?

If you found any bug or need more documentation, immediately feel an issue in GitHub. I should read most of them.

If you want to submit a PR to improve the project, that would be awesome. If, in top of that, you want to run the tests (yeah, because there are tests! A few of them...) before submitting it, you are just amasing but also don't run the tests globally. If you do sbt test, the whole universe will nearly collapse due to classpath errors that are totally beyond the understanding of the current me. Run them by project, like playEdge/test inside an sbt console. And even so, they might fail because of a LinkageError, just run them twice and it will work... I don't know why... I drank too much whisky trying to understand it so I just stopped. If you are a classpath God, just ping me and I will have questions for you.


  • Test: run all tests with sbt testAll (if java.lang.LinkageError, just re-run the command)
  • Publish: update version numbers in build.sbt and run sbt release (be sure to either reload inside sbt or start a new sbt)
  • Scaladoc: to manually generate all scaladoc, run sbt scaladoc
  • Publish docs: to manually build and push online the doc website, run sbt publish-doc
  • Docs: to have a locally running doc website:


This software is licensed under the Apache 2 license, quoted below.

Copyright 2015 Paul Dijou (http://pauldijou.fr).

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this project except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.