1# jwt-go
2
3[](https://github.com/golang-jwt/jwt/actions/workflows/build.yml)
4[](https://pkg.go.dev/github.com/golang-jwt/jwt/v5)
6[](https://coveralls.io/github/golang-jwt/jwt?branch=main)
7
8A [go](http://www.golang.org) (or 'golang' for search engine friendliness)
9implementation of [JSON Web
10Tokens](https://datatracker.ietf.org/doc/html/rfc7519).
11
12Starting with [v4.0.0](https://github.com/golang-jwt/jwt/releases/tag/v4.0.0)
13this project adds Go module support, but maintains backward compatibility with
14older `v3.x.y` tags and upstream `github.com/dgrijalva/jwt-go`. See the
15[`MIGRATION_GUIDE.md`](./MIGRATION_GUIDE.md) for more information. Version
16v5.0.0 introduces major improvements to the validation of tokens, but is not
17entirely backward compatible.
18
19> After the original author of the library suggested migrating the maintenance
20> of `jwt-go`, a dedicated team of open source maintainers decided to clone the
21> existing library into this repository. See
22> [dgrijalva/jwt-go#462](https://github.com/dgrijalva/jwt-go/issues/462) for a
23> detailed discussion on this topic.
24
25
26**SECURITY NOTICE:** Some older versions of Go have a security issue in the
27crypto/elliptic. The recommendation is to upgrade to at least 1.15 See issue
28[dgrijalva/jwt-go#216](https://github.com/dgrijalva/jwt-go/issues/216) for more
29detail.
30
31**SECURITY NOTICE:** It's important that you [validate the `alg` presented is
32what you
33expect](https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/).
34This library attempts to make it easy to do the right thing by requiring key
35types to match the expected alg, but you should take the extra step to verify it in
36your usage. See the examples provided.
37
38### Supported Go versions
39
40Our support of Go versions is aligned with Go's [version release
41policy](https://golang.org/doc/devel/release#policy). So we will support a major
42version of Go until there are two newer major releases. We no longer support
43building jwt-go with unsupported Go versions, as these contain security
44vulnerabilities that will not be fixed.
45
46## What the heck is a JWT?
47
48JWT.io has [a great introduction](https://jwt.io/introduction) to JSON Web
49Tokens.
50
51In short, it's a signed JSON object that does something useful (for example,
52authentication). It's commonly used for `Bearer` tokens in Oauth 2. A token is
53made of three parts, separated by `.`'s. The first two parts are JSON objects,
54that have been [base64url](https://datatracker.ietf.org/doc/html/rfc4648)
55encoded. The last part is the signature, encoded the same way.
56
57The first part is called the header. It contains the necessary information for
58verifying the last part, the signature. For example, which encryption method
59was used for signing and what key was used.
60
61The part in the middle is the interesting bit. It's called the Claims and
62contains the actual stuff you care about. Refer to [RFC
637519](https://datatracker.ietf.org/doc/html/rfc7519) for information about
64reserved keys and the proper way to add your own.
65
66## What's in the box?
67
68This library supports the parsing and verification as well as the generation and
69signing of JWTs. Current supported signing algorithms are HMAC SHA, RSA,
70RSA-PSS, and ECDSA, though hooks are present for adding your own.
71
72## Installation Guidelines
73
741. To install the jwt package, you first need to have
75 [Go](https://go.dev/doc/install) installed, then you can use the command
76 below to add `jwt-go` as a dependency in your Go program.
77
78```sh
79go get -u github.com/golang-jwt/jwt/v5
80```
81
822. Import it in your code:
83
84```go
85import "github.com/golang-jwt/jwt/v5"
86```
87
88## Usage
89
90A detailed usage guide, including how to sign and verify tokens can be found on
91our [documentation website](https://golang-jwt.github.io/jwt/usage/create/).
92
93## Examples
94
95See [the project documentation](https://pkg.go.dev/github.com/golang-jwt/jwt/v5)
96for examples of usage:
97
98* [Simple example of parsing and validating a
99 token](https://pkg.go.dev/github.com/golang-jwt/jwt/v5#example-Parse-Hmac)
100* [Simple example of building and signing a
101 token](https://pkg.go.dev/github.com/golang-jwt/jwt/v5#example-New-Hmac)
102* [Directory of
103 Examples](https://pkg.go.dev/github.com/golang-jwt/jwt/v5#pkg-examples)
104
105## Compliance
106
107This library was last reviewed to comply with [RFC
1087519](https://datatracker.ietf.org/doc/html/rfc7519) dated May 2015 with a few
109notable differences:
110
111* In order to protect against accidental use of [Unsecured
112 JWTs](https://datatracker.ietf.org/doc/html/rfc7519#section-6), tokens using
113 `alg=none` will only be accepted if the constant
114 `jwt.UnsafeAllowNoneSignatureType` is provided as the key.
115
116## Project Status & Versioning
117
118This library is considered production ready. Feedback and feature requests are
119appreciated. The API should be considered stable. There should be very few
120backward-incompatible changes outside of major version updates (and only with
121good reason).
122
123This project uses [Semantic Versioning 2.0.0](http://semver.org). Accepted pull
124requests will land on `main`. Periodically, versions will be tagged from
125`main`. You can find all the releases on [the project releases
126page](https://github.com/golang-jwt/jwt/releases).
127
128**BREAKING CHANGES:** A full list of breaking changes is available in
129`VERSION_HISTORY.md`. See [`MIGRATION_GUIDE.md`](./MIGRATION_GUIDE.md) for more information on updating
130your code.
131
132## Extensions
133
134This library publishes all the necessary components for adding your own signing
135methods or key functions. Simply implement the `SigningMethod` interface and
136register a factory method using `RegisterSigningMethod` or provide a
137`jwt.Keyfunc`.
138
139A common use case would be integrating with different 3rd party signature
140providers, like key management services from various cloud providers or Hardware
141Security Modules (HSMs) or to implement additional standards.
142
143| Extension | Purpose | Repo |
144| --------- | -------------------------------------------------------------------------------------------------------- | ------------------------------------------ |
145| GCP | Integrates with multiple Google Cloud Platform signing tools (AppEngine, IAM API, Cloud KMS) | https://github.com/someone1/gcp-jwt-go |
146| AWS | Integrates with AWS Key Management Service, KMS | https://github.com/matelang/jwt-go-aws-kms |
147| JWKS | Provides support for JWKS ([RFC 7517](https://datatracker.ietf.org/doc/html/rfc7517)) as a `jwt.Keyfunc` | https://github.com/MicahParks/keyfunc |
148
149*Disclaimer*: Unless otherwise specified, these integrations are maintained by
150third parties and should not be considered as a primary offer by any of the
151mentioned cloud providers
152
153## More
154
155Go package documentation can be found [on
156pkg.go.dev](https://pkg.go.dev/github.com/golang-jwt/jwt/v5). Additional
157documentation can be found on [our project
158page](https://golang-jwt.github.io/jwt/).
159
160The command line utility included in this project (cmd/jwt) provides a
161straightforward example of token creation and parsing as well as a useful tool
162for debugging your own integration. You'll also find several implementation
163examples in the documentation.
164
165[golang-jwt](https://github.com/orgs/golang-jwt) incorporates a modified version
166of the JWT logo, which is distributed under the terms of the [MIT
167License](https://github.com/jsonwebtoken/jsonwebtoken.github.io/blob/master/LICENSE.txt).