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titleshortTitleintroversionstopics
Generating a JSON Web Token (JWT) for a GitHub App
Generate a JWT
Learn how to create a JSON Web Token (JWT) to authenticate to certain REST API endpoints with your {% data variables.product.prodname_github_app %}.
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GitHub Apps

About JSON Web Tokens (JWTs)

In order to authenticate as an app or generate an installation access token, you must generate a JSON Web Token (JWT). If a REST API endpoint requires a JWT, the documentation for that endpoint will indicate that you must use a JWT to access the endpoint.

Your JWT must be signed using the RS256 algorithm and must contain the following claims.

ClaimMeaningDetails
iatIssued AtThe time that the JWT was created. To protect against clock drift, we recommend that you set this 60 seconds in the past and ensure that your server's date and time is set accurately (for example, by using the Network Time Protocol).
expExpires AtThe expiration time of the JWT, after which it can't be used to request an installation token. The time must be no more than 10 minutes into the future.
issIssuerThe {% ifversion client-id-for-app %}client ID or {% endif %}application ID of your {% data variables.product.prodname_github_app %}. This value is used to find the right public key to verify the signature of the JWT. You can find your app's ID{% ifversion client-id-for-app %}s{% endif %} on the settings page for your {% data variables.product.prodname_github_app %}.{% ifversion client-id-for-app %} Use of the client ID is recommended.{% endif %} For more information about navigating to the settings page for your {% data variables.product.prodname_github_app %}, see AUTOTITLE.
algMessage authentication code algorithmThis should be RS256 since your JWT must be signed using the RS256 algorithm.

To use a JWT, pass it in the Authorization header of an API request. For example:

curl --request GET \ --url "{% data variables.product.rest_url %}/app" \ --header "Accept: application/vnd.github+json" \ --header "Authorization: Bearer YOUR_JWT" \ --header "X-GitHub-Api-Version: {{ allVersions[currentVersion].latestApiVersion }}"

{% data reusables.getting-started.bearer-vs-token %}

Generating a JSON Web Token (JWT)

Most programming languages have a package that can generate a JWT. In all cases, you must have a private key and the ID of your {% data variables.product.prodname_github_app %}. For more information about generating a private key, see AUTOTITLE. You can find your app's ID with the GET /app REST API endpoint. For more information, see Apps in the REST API documentation.

Note

Instead of creating a JWT, you can use {% data variables.product.company_short %}'s Octokit SDKs to authenticate as an app. The SDK will take care of generating a JWT for you and will regenerate the JWT once the token expires. For more information, see Scripting with the REST API and JavaScript.

Example: Using Ruby to generate a JWT

Note

You must run gem install jwt to install the jwt package in order to use this script.

In the following example, replace YOUR_PATH_TO_PEM with the file path where your private key is stored. Replace {% ifversion client-id-for-app %}YOUR_CLIENT_ID{% else %}YOUR_APP_ID{% endif %} with the ID of your app. Make sure to enclose the values for YOUR_PATH_TO_PEM and {% ifversion client-id-for-app %}YOUR_CLIENT_ID{% else %}YOUR_APP_ID{% endif %} in double quotes.

require'openssl'require'jwt'# https://rubygems.org/gems/jwt# Private key contentsprivate_pem=File.read("YOUR_PATH_TO_PEM")private_key=OpenSSL::PKey::RSA.new(private_pem)# Generate the JWTpayload={# issued at time, 60 seconds in the past to allow for clock driftiat: Time.now.to_i - 60,# JWT expiration time (10 minute maximum)exp: Time.now.to_i + (10 * 60),{% ifversion client-id-for-app %}# {% data variables.product.prodname_github_app %}'s client ID iss: "YOUR_CLIENT_ID"{% else %}# {% data variables.product.prodname_github_app %}'s app ID iss: "YOUR_APP_ID"{% endif %}}jwt = JWT.encode(payload, private_key, "RS256")puts jwt

Example: Using Python to generate a JWT

Note

You must run pip install PyJWT cryptography to install the PyJWT and the cryptography packages in order to use this script.

#!/usr/bin/env python3importsysimporttimeimportjwt# Get PEM file pathiflen(sys.argv) >1: pem=sys.argv[1] else: pem=input("Enter path of private PEM file: ") {%ifversionclient-id-for-app%} # Get the Client IDiflen(sys.argv) >2: client_id=sys.argv[2] else: client_id=input("Enter your Client ID: ") {%else%} # Get the App IDiflen(sys.argv) >2: app_id=sys.argv[2] else: app_id=input("Enter your APP ID: ") {%endif%} # Open PEMwithopen(pem, 'rb') aspem_file: signing_key=pem_file.read() payload= { # Issued at time'iat': int(time.time()), # JWT expiration time (10 minutes maximum)'exp': int(time.time()) +600, {%ifversionclient-id-for-app%} # {% data variables.product.prodname_github_app %}'s client ID'iss': client_id{%else%} # {% data variables.product.prodname_github_app %}'s app ID'iss': app_id{%endif%} } # Create JWTencoded_jwt=jwt.encode(payload, signing_key, algorithm='RS256') print(f"JWT: {encoded_jwt}")

This script will prompt you for the file path where your private key is stored and for the ID of your app. Alternatively, you can pass those values as inline arguments when you execute the script.

Example: Using Bash to generate a JWT

Note

You must pass your {% ifversion client-id-for-app %}Client ID{% else %}App ID{% endif %} and the file path where your private key is stored as arguments when running this script.

#!/usr/bin/env bashset -o pipefail {% ifversion client-id-for-app %} client_id=$1# Client ID as first argument {% else %} app_id=$1# App ID as first argument {% endif %} pem=$( cat $2)# file path of the private key as second argument now=$(date +%s) iat=$((${now}-60))# Issues 60 seconds in the past exp=$((${now}+600))# Expires 10 minutes in the futureb64enc() { openssl base64 | tr -d '='| tr '/+''_-'| tr -d '\n'; } header_json='{ "typ":"JWT", "alg":"RS256"}'# Header encode header=$(echo -n "${header_json}"| b64enc ) payload_json="{\"iat\":${iat},\"exp\":${exp}, {% ifversion client-id-for-app %}\"iss\":\"${client_id}\"{% else %}\"iss\":\"${app_id}\"{% endif %}}"# Payload encode payload=$(echo -n "${payload_json}"| b64enc )# Signature header_payload="${header}"."${payload}" signature=$( openssl dgst -sha256 -sign <(echo -n "${pem}") \<(echo -n "${header_payload}")| b64enc)# Create JWT JWT="${header_payload}"."${signature}"printf'%s\n'"JWT: $JWT"

Example: Using PowerShell to generate a JWT

In the following example, replace YOUR_PATH_TO_PEM with the file path where your private key is stored. Replace {% ifversion client-id-for-app %}YOUR_CLIENT_ID{% else %}YOUR_APP_ID{% endif %} with the ID of your app. Make sure to enclose the values for YOUR_PATH_TO_PEM in double quotes.

#!/usr/bin/env pwsh {% ifversion client-id-for-app %} $client_id= YOUR_CLIENT_ID {%else%} $app_id= YOUR_APP_ID {% endif %} $private_key_path="YOUR_PATH_TO_PEM"$header= [Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes((ConvertTo-Json-InputObject @{ alg="RS256"typ="JWT" }))).TrimEnd('=').Replace('+','-').Replace('/','_'); $payload= [Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes((ConvertTo-Json-InputObject @{ iat= [System.DateTimeOffset]::UtcNow.AddSeconds(-10).ToUnixTimeSeconds() exp= [System.DateTimeOffset]::UtcNow.AddMinutes(10).ToUnixTimeSeconds() {% ifversion client-id-for-app %} iss=$client_id {%else%} iss=$app_id {% endif %} }))).TrimEnd('=').Replace('+','-').Replace('/','_'); $rsa= [System.Security.Cryptography.RSA]::Create() $rsa.ImportFromPem((Get-Content$private_key_path-Raw)) $signature= [Convert]::ToBase64String($rsa.SignData([System.Text.Encoding]::UTF8.GetBytes("$header.$payload"), [System.Security.Cryptography.HashAlgorithmName]::SHA256, [System.Security.Cryptography.RSASignaturePadding]::Pkcs1)).TrimEnd('=').Replace('+','-').Replace('/','_') $jwt="$header.$payload.$signature"Write-Host$jwt
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