@kapa.ai I need to add a customized header parameter to an OAuth2.0 token request. This is using client credentials grant type. Should I add this in the Refresh Request Headers section? Additionally, in that parameter I need to base64 encode a string. Is there a function or other way to do that in that config field or do I need to do the encoding separately? The string to be encoded will be the same for all requests.

Adding Custom Headers to OAuth2.0 Token Requests Where to Add the Header Yes, Refresh Request Headers is the correct place to add custom headers for the token request. In the YAML config, this corresponds to the

refresh_request_headers

field on the

OAuthAuthenticator

. [YAML Reference] Base64 Encoding You do not need to encode the string separately. Airbyte's declarative OAuth supports a

b64encode

pipe/filter function directly within the template interpolation syntax. [Template Variables] For example, to base64-encode a static string:

refresh_request_headers:
  Authorization: "Basic {{ 'your_static_string_here' | b64encode }}"
  Content-Type: "application/x-www-form-urlencoded"

Or, if the string is a combination of your client ID and secret (a common pattern):

refresh_request_headers:
  Authorization: "Basic {{ (config['client_id'] ~ ':' ~ config['client_secret']) | b64encode }}"
  Content-Type: "application/x-www-form-urlencoded"

This pattern is used in real connectors — for example, the Airtable and Gong connectors both use this approach: [Airtable manifest] [Gong manifest]

refresh_request_headers:
  Authorization: "Basic {{ [config['credentials']['client_id'], config['credentials']['client_secret']] | join(':') | base64encode }}"
  Content-Type: "application/x-www-form-urlencoded"

> Note: Both

b64encode

and

base64encode

appear in the examples in the knowledge sources — use whichever is consistent with your CDK version. Since your string is the same for all requests, you can simply hardcode it as a literal string in the template:

refresh_request_headers:
  YourCustomHeader: "{{ 'my_static_value' | b64encode }}"

This keeps everything within the declarative config — no separate pre-encoding step needed. 👍 0 button 👎 0 button ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.