Getting 401 error when trying to exchange temporary code for Notion access token

Other Questions Notion
1

Hey everyone, I’m having trouble with the Notion API. I’m trying to exchange a temporary code for an access token, but I keep getting a 401 unauthorized error. Here’s what I’ve tried:

const getAccessToken = async () => {
  const response = await fetch('https://api.notion.com/v1/oauth/token', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      client_id: myNotionClientId,
      client_secret: myNotionClientSecret,
      code: temporaryCode,
      grant_type: 'authorization_code'
    })
  });

  return response.json();
};

I’ve double-checked my client ID and secret, but still no luck. Am I missing something obvious? The Notion docs aren’t very helpful on this. Oh, and I’m using localhost as my redirect URL in the integration setup. Any ideas what could be going wrong?

2

hey grace, i’ve run into this before. double check ur redirect_uri in the request body matches exactly what u set in notion’s integration settings. also, make sure the temporary code hasn’t expired - they’re only valid for like 10 mins. if that doesn’t help, try regenerating ur client secret. good luck!

3

I encountered a similar issue when integrating with Notion’s API. Have you verified the timestamp of your temporary code? These codes have a short lifespan, typically around 10 minutes. If you’re debugging and the code expires, you’ll consistently receive 401 errors.

Another potential culprit could be your redirect URI. Ensure it’s an exact match, including the protocol (http vs https) and any trailing slashes. Notion is quite strict about this.

Lastly, check your request headers. Some developers forget to include the ‘Authorization’ header with the ‘Bearer’ prefix for the access token once obtained. This can lead to 401 errors in subsequent API calls.

If none of these solve your issue, I’d recommend using a tool like Postman to isolate the problem. It can help identify if the issue lies in your code or the API itself.

4

I’ve dealt with similar issues when integrating Notion API. One thing that often gets overlooked is the Authorization header. Make sure you’re including it in your request with the Basic auth scheme, like this:

headers: {
  'Authorization': 'Basic ' + Buffer.from(myNotionClientId + ':' + myNotionClientSecret).toString('base64'),
  'Content-Type': 'application/json'
}

Also, verify that your temporary code hasn’t been used before. Notion’s codes are single-use only. If you’ve already attempted an exchange with that code, you’ll need to start the OAuth flow again to get a fresh one.

Lastly, check if your integration has the necessary capabilities enabled in the Notion dashboard. Sometimes permissions can cause unexpected 401 errors. Hope this helps!