In the OAuth2 authorization code flow, the fourth step involves exchanging the authorization code for an access token. This is done by sending a POST request to the Authorization Server with certain parameters. Here's an example of how you can do this in JavaScript:

javascript const code = "authorization_code_received_from_auth_server"   const tokenUrl = "https://{project.slug}.<http://projects.oryapis.com/oauth2/token|projects.oryapis.com/oauth2/token>"   const requestBody = `grant_type=authorization_code&client_id=${clientId}&code_verifier=${codeVerifier}&code=${code}`      fetch(tokenUrl, {    method: "POST",    headers: { "Content-Type": "application/x-www-form-urlencoded" },    body: requestBody,   })    .then((response) => response.json())    .then((data) => console.log(data))    .catch((error) => console.error(error))

In this code,

code

is the authorization code received from the Authorization Server.

tokenUrl

is the URL of the token endpoint of the Authorization Server.

requestBody

is a string that contains the parameters of the POST request. The

fetch

function is used to send the POST request to the

tokenUrl

. The response from the server is then parsed as JSON and logged to the console. Please note that this is a general example. The actual values of

code

,

tokenUrl

, and

requestBody

will depend on your specific application and Ory setup. For more information, you can refer to the [Ory documentation on the OAuth2 authorization code flow](https://www.ory.sh/docs/oauth2-oidc/authorization-code-flow#step-4-exchange-code-for-token).

If you're not using PKCE (Proof Key for Code Exchange), the process of exchanging the authorization code for a token is slightly different. Here's an example of how you can do this in JavaScript:

javascript const code = "authorization_code_received_from_auth_server"   const tokenUrl = "https://{project.slug}.<http://projects.oryapis.com/oauth2/token|projects.oryapis.com/oauth2/token>"   const requestBody = `grant_type=authorization_code&client_id=${clientId}&code=${code}`      fetch(tokenUrl, {    method: "POST",    headers: { "Content-Type": "application/x-www-form-urlencoded" },    body: requestBody,   })    .then((response) => response.json())    .then((data) => console.log(data))    .catch((error) => console.error(error))

In this code,

code

is the authorization code received from the Authorization Server.

tokenUrl

is the URL of the token endpoint of the Authorization Server.

requestBody

is a string that contains the parameters of the POST request. The

fetch

function is used to send the POST request to the

tokenUrl

. The response from the server is then parsed as JSON and logged to the console. Please note that this is a general example. The actual values of

code

,

tokenUrl

, and

requestBody

will depend on your specific application and Ory setup. For more information, you can refer to the [Ory documentation on the OAuth2 authorization code flow](https://www.ory.sh/docs/oauth2-oidc/authorization-code-flow#exchange-code-for-token-1).

The OAuth client secret is used to authenticate the client application to the authorization server. It is typically sent as part of the request to exchange the authorization code for an access token. In the context of Ory, the client secret can be supplied in different ways depending on the authentication method used: 1. Basic Authentication: The client sends its client ID and client secret as part of the Authorization header in an HTTP request. The Authorization header contains a Base64-encoded string of

{URL-encoded-client-ID}:{URL-encoded-client-secret}

. Here's an example:

javascript const clientID = "the-client-id"   const clientSecret = "the-secret-id"   const basicAuth = bas64_encode(url_encode(clientID) + ":" + url_encode(clientSecret))      const requestOptions = {    method: "POST",    headers: {    Authorization: "Basic " + basicAuth,    "Content-Type": "application/x-www-form-urlencoded",    },    body: "grant_type=client_credentials&scope=read",   }      fetch("<https://your-project.projects.oryapis.com/oauth2/token>", requestOptions)    .then((response) => response.json())    .then((data) => console.log(data))

(Source: [Ory Documentation - Basic Authentication](https://www.ory.sh/docs/oauth2-oidc/client-credentials#basic-authentication)) 2. Body Authentication: The client sends its client ID and client secret as parameters in the body of the HTTP request. Here's an example:

javascript const clientID = "the-client-id"   const clientSecret = "the-secret-id"      const qs = new URLSearchParams()   qs.set("grant_type", "client_credentials")   qs.set("client_id", clientID)   qs.set("client_secret", clientSecret)   qs.set("scope", read)      const requestOptions = {    method: "POST",    headers: { "Content-Type": "application/x-www-form-urlencoded" },    body: qs.toString(),   }      fetch("<https://your-project.projects.oryapis.com/oauth2/token>", requestOptions)    .then((response) => response.json())    .then((data) => console.log(data))

(Source: [Ory Documentation - Body Authentication](https://www.ory.sh/docs/oauth2-oidc/client-credentials#body-authentication)) Please replace

"the-client-id"

and

"the-secret-id"

with your actual client ID and client secret. Also, replace

"<https://your-project.projects.oryapis.com/oauth2/token>"

with your actual token endpoint URL.