Open Cloud supports the OAuth 2.0 authorization flow with and without PKCE, depending on whether your clients are confidential or public.
- Confidential clients are apps that are capable of keeping credentials confidential, such as a website that can securely store and retrieve secrets on its backend.
- Public clients are apps that can't keep secrets, such as mobile and web browser apps.
We recommend the OAuth 2.0 authorization code flow with PKCE for all clients and require it for public clients.
Store the client secret in a secure place and never expose it to the public. Bad actors can use it to impersonate your application.
To implement the authorization code flow, your app performs the following steps:
- Generate a code verifier and code challenge (PKCE only). This lets you include a challenge in your requests rather than the client secret, which improves security.
- Send a GET request to the authorization endpoint with the appropriate parameters.
- Handle the authorization callback. After obtaining authorization, use the authorization code from Roblox in a redirect request to the URL you specified during app creation. Parse the authorization code for later use.
- Send a POST request to the token endpoint with the authorization code. If successful, you receive access and refresh tokens with which to make API calls.
- Call any Open Cloud API that supports OAuth 2.0 authentication based on the reference documentation for the resources you want to access.
The following sections describe each step in greater depth.
Generate a code challenge (for PKCE only)
Before initiating the authorization process, you need to generate a code challenge from a code verifier. You can use libraries or built-in functions in the programming language of your choice to create the code verifier, calculate the hash, and perform Base64 encoding to generate the code challenge.
When creating the code verifier, only use unreserved characters, including uppercase and lowercase letters (A-Z, a-z), decimal digits (0-9), hyphen (-), period (.), underscore (_), and tilde (~), with a minimum length of 43 characters and a maximum length of 128 characters.
The following example shows how to use Javascript to create a code verifier and generate the code challenge using the SHA-256 hashing algorithm:
Generate Code Challenge
const crypto = require('crypto');
// base64URL encode the verifier and challenge
function base64URLEncode(str) {
return str.toString('base64')
.replace(/\+/g, '-')
.replace(/\//g, '_')
.replace(/=/g, '');
}
// create sha256 hash from code verifier
function sha256(buffer) {
return crypto.createHash('sha256').update(buffer).digest(`base64`);
}
// create a random code verifier
var code_verifier = base64URLEncode(crypto.randomBytes(32));
// generate a challenge from the code verifier
var code_challenge = base64URLEncode(sha256(code_verifier));
For PKCE, you need both the code verifier and challenge values in later steps.
Construct the authorization URL
See the authorization endpoint reference documentation for complete information on how to construct the authorization URL.
To initiate the user authorization process, construct an authorization URL with the required parameters:
- client_id: Your app's client ID obtained after registering your app.
- redirect_uri: Your app's redirect URI, the re-entry point of your app.
- scope: The requested scopes that define the access permissions your app needs in a space-separated list.
- response_type: Set it to code to indicate the authorization code flow.
Required for PKCE only
- code_challenge: The code challenge generated from a code verifier.
- code_challenge_method: Set this parameter value to S256 to indicate that the code challenge was transformed using the SHA-256 algorithm, the most widely supported and secure code challenge method.
- state: An opaque, secure random value to maintain state between the request and callback.
Required for non-PKCE only
- client_secret: Your app's client secret obtained after registering your app. If you are using authentication with PKCE, omit this parameter. Your authorization request URL must be well formatted, like in the following example:
Example PKCE Authorization URL
When users visit the URL, they are taken through the authorization flow. If successful, Roblox redirects the user to the specified redirect_uri.
Handle authorization callbacks
When an authorization flow is successful, your app receives a GET request from the Roblox authorization server at the redirect_uri that you specified. In the request, you receive code (authorization code) and state(if you provided a value previously) parameters.
The code parameter contains an authorization code that the app can exchange for an access token from the authorization server. Most backend server languages have standard ways to access query parameters as decoded objects. You'll need to obtain the code parameter and use it to exchange for access tokens.
The state parameter is an opaque value that you initially provided in the authorization request. You can use this parameter to maintain the state or context of the authorization process.
For example, you might receive a GET request with the following URL if you specified your redirect URI to be https://example.com/redirect.
Example Redirect URL
If authorization fails, your app receives a GET request to the specified redirect URL with the error, error_description, and state (if applicable) parameters.
- The error parameter indicates the specific OAuth 2.0 error that occurred during the authorization process.
- The error_description parameter provides additional details of the error.
- The state parameter helps your app maintain state in the case of a failure.
Exchange an authorization code for access tokens
When you have parsed the authorization code, exchange it for tokens to access desired Roblox resources:
Request an access token and refresh token by sending a POST request to the token exchange endpoint. The request must include the authorization code, client ID, and the code verifier value (PKCE) or client secret (non-PKCE) in x-www-form-urlencoded format.
Parse the applicable tokens from the response received. The access token is valid for 15 minutes. Store the refresh token securely, typically on the server side, so you can use it to obtain new tokens in the future.
Example Token Endpoint Response{"access_token": "eyJhbGciOiJFUzI1NiIsImtpZCI6IlBOeHhpb2JFNE8zbGhQUUlUZG9QQ3FCTE81amh3aXZFS1pHOWhfTGJNOWMiLCJ0eXAiOiJKV11234.eyJzdWIiOiIyMDY3MjQzOTU5IiwiYWlkIjoiM2Q2MWU3NDctM2ExNS00NTE4LWJiNDEtMWU3M2VhNDUyZWIwIiwic2NvcGUiOiJvcGVuaWQ6cmVhZCBwcm9maWxlOnJlYWQiLCJqdGkiOiJBVC5QbmFWVHpJU3k2YkI5TG5QYnZpTCIsIm5iZiI6MTY5MTYzOTY5OCwiZXhwIjoxNjkxNjQwNTk4LCJpYXQiOjE2OTE2Mzk2OTgsImlzcyI6Imh0dHBzOi8vYXBpcy5yb2Jsb3guY29tL29hdXRoLyIsImF1ZCI6IjcyOTA2MTAzOTc5ODc5MzQ5Nj1234.BjwMkC8Q5a_iP1Q5Th8FrS7ntioAollv_zW9mprF1ats9CD2axCvupZydVzYphzQ8TawunnYXp0Xe8k0t8ithg","refresh_token": "eyJhbGciOiJkaXIiLCJlbmMiOiJBMjU2Q0JDLUhTNTEyIiwia2lkIjoidGpHd1BHaURDWkprZEZkREg1dFZ5emVzRWQyQ0o1NDgtUi1Ya1J1TTBBRSIsInR5cCI6IkpXVCJ9..nKYZvjvXH6msDG8Udluuuw.PwP-_HJIjrgYdY-gMR0Q3cabNwIbmItcMEQHx5r7qStVVa5l4CbrKwJvjY-w9xZ9VFb6P70WmXndNifnio5BPZmivW5QkJgv5_sxLoCwsqB1bmEkz2nFF4ANLzQLCQMvQwgXHPMfCK-lclpVEwnHk4kemrCFOvfuH4qJ1V0Q0j0WjsSU026M67zMaFrrhSKwQh-SzhmXejhKJOjhNfY9hAmeS-LsLLdszAq_JyN7fIvZl1fWDnER_CeDAbQDj5K5ECNOHAQ3RemQ2dADVlc07VEt2KpSqUlHlq3rcaIcNRHCue4GfbCc1lZwQsALbM1aSIzF68klXs1Cj_ZmXxOSOyHxwmbQCHwY7aa16f3VEJzCYa6m0m5U_oHy84iQzsC-_JvBaeFCachrLWmFY818S-nH5fCIORdYgc4s7Fj5HdULnnVwiKeQLKSaYsfneHtqwOc_ux2QYv6Cv6Xn04tkB2TEsuZ7dFwPI-Hw2O30vCzLTcZ-Fl08ER0J0hhq4ep7B641IOnPpMZ1m0gpJJRPbHX_ooqHol9zHZ0gcLKMdYy1wUgsmn_nK_THK3m0RmENXNtepyLw_tSd5vqqIWZ5NFglKSqVnbomEkxneEJRgoFhBGMZiR-3FXMaVryUjq-N.Q_t4NGxTUSMsLVEppkTu0Q6rwt2rKJfFGuvy3s12345","token_type": "Bearer","expires_in": 899,"id_token": "eyJhbGciOiJFUzI1NiIsImtpZCI6IkNWWDU1Mi1zeWh4Y1VGdW5vNktScmtReFB1eW15YTRQVllodWdsd3hnNzgiLCJ0eXAiOiJKV11234.eyJzdWIiOiIyMDY3MjQzOTU5IiwibmFtZSI6ImxpbmtzZ29hdCIsIm5pY2tuYW1lIjoibGlua3Nnb2F0IiwicHJlZmVycmVkX3VzZXJuYW1lIjoibGlua3Nnb2F0IiwiY3JlYXRlZF9hdCI6MTYwNzM1NDIzMiwicHJvZmlsZSI6Imh0dHBzOi8vd3d3LnJvYmxveC5jb20vdXNlcnMvMjA2NzI0Mzk1OS9wcm9maWxlIiwibm9uY2UiOiIxMjM0NSIsImp0aSI6IklELnltd3ZjTUdpOVg4azkyNm9qd1I5IiwibmJmIjoxNjkxNjM5Njk4LCJleHAiOjE2OTE2NzU2OTgsImlhdCI6MTY5MTYzOTY5OCwiaXNzIjoiaHR0cHM6Ly9hcGlzLnJvYmxveC5jb20vb2F1dGgvIiwiYXVkIjoiNzI5MDYxMDM5Nzk4NzkzNDk2NCJ9.kZgCMJQGsariwCi8HqsUadUBMM8ZOmf_IPDoWyQY9gVX4Kx3PubDz-Q6MvZ9eU5spNFz0-PEH-G2WSvq2ljDyg","scope": "openid profile"}
Make a call to a resource method
Now that you have the required access token, you can use it to make authenticated calls to resource methods. Include the access token in the header of all API requests to authorize them.
For example, you can test if your app functions correctly by going through the entire authorization flow and then making a GET request to the user information endpoint with an access token. Ensure you have the openid or both the openid and profile scopes before calling this endpoint. If successful, the response from that endpoint looks like this:
Example User Information Response
{
"sub": "12345678",
"name": "Jane Doe",
"nickname": "robloxjanedoe",
"preferred_username": "robloxjanedoe",
"created_at": 1607354232,
"profile": "https://www.roblox.com/users/12345678/profile"
}