Using Client Credential OAuth in n8n

Dipped my toe into the world of n8n recently. With most platforms, you run into something that doesn’t make a ton of sense. In this case, n8n currently doesn’t provide an option for setting the “client credentials” grant flow for OAuth authentication which is (still) used by a large number of services out there like some Twitter API calls. Luckily, using HTTP requests in a workflow like easily perform what a “client credential” based OAuth token would do if it were a configuration option.

Twitter’s authentication documentation says that for this authentication flow, we’ll need to make a request to https://api.twitter.com/oauth2/token with Basic authentication containing the API_KEY and API_SECRET_KEY of the application I'll be authenticating with along with a query parameter of grant_type=client_credentials. Once the Node is created and ran successfully, the authentication token will be in a JSON object under the access_token key. The next Node can then use that token as a variable in a header like Authorization: Bearer {{$node["Get Twitter Auth"].json["access_token"]}}.

Here are the example Nodes that can be used in a workflow:

{ "nodes": [ { "parameters": { "authentication": "basicAuth", "requestMethod": "POST", "url": "https://api.twitter.com/oauth2/token", "options": {}, "queryParametersUi": { "parameter": [ { "name": "grant_type", "value": "client_credentials" } ] } }, "name": "Get Twitter Auth", "type": "n8n-nodes-base.httpRequest", "typeVersion": 1, "position": [ 460, 280 ], "credentials": { "httpBasicAuth": { "id": "3", "name": "Twitter Basic credential" } } }, { "parameters": { "url": "https://api.twitter.com/1.1/followers/list.json?cursor=-1&screen_name=tuckner&count=25", "options": {}, "headerParametersUi": { "parameter": [ { "name": "Authorization", "value": "=Bearer {{$node[\"Get Twitter Auth\"].json[\"access_token\"]}}" } ] } }, "name": "Get Twitter Followers", "type": "n8n-nodes-base.httpRequest", "typeVersion": 1, "position": [ 660, 280 ] } ], "connections": { "Get Twitter Auth": { "main": [ [ { "node": "Get Twitter Followers", "type": "main", "index": 0 } ] ] } } }

Originally published at https://johntuckner.me.