Hi everyone,
I’m building a multi-user SaaS workflow where each user connects their Gmail account to allow my backend to create Gmail Drafts on their behalf using n8n. I’m stuck at one major point: How to dynamically inject each user’s Gmail OAuth credentials into the Gmail node at runtime.
My Setup
I have multiple users, each with:
- Gmail client ID
- Gmail client secret
- Gmail access token
- Gmail refresh token
All credentials are encrypted and stored inside my database.
When a user signs in, my backend receives their tokens successfully.
Now I need n8n to:
Automatically pick that user’s credentials
Use them in Gmail node
Create a Draft (not send email)
Using an HTTP Request or gmail node → n8n workflow trigger
The Problem
Gmail node requires selecting a credential from the credentials list — but I need per-user dynamic credentials.
I tried:
Passing tokens via parameters
Creating credential via API
Using Expressions to set OAuth fields
Using HTTP node with raw Google API
But Gmail node does not allow dynamic Client ID / Client Secret / Tokens.
I want n8n to automatically:
Receive tokens from backend
Generate credential entry programmatically (if needed)
Use those credentials for that workflow run
Create Gmail Draft
Questions
Is there any recommended way to set Gmail OAuth credentials dynamically for each user?
Something like runtime credentials injection?
Can I create or update Gmail OAuth credentials via n8n API whenever a user logs in?
If yes, how do I attach those credentials to the workflow execution?
Is the only solution to skip Gmail Node entirely and use HTTP Request Node with Google API raw endpoints?
If so, how do I correctly handle:
access token refresh
draft creation
MIME/base64 email body encoding?
Important Requirement
I do not want to send emails
→ Only save email to Gmail Drafts.
What I need guidance on
Best architecture to handle per-user Gmail credentials
Whether dynamic OAuth is supported
Example of programmatically creating a draft using HTTP node with user-specific tokens
How others have implemented multi-user Gmail integration in n8n
Any help or example workflows would be greatly appreciated!
Thanks!
Describe the problem/error/question
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Information on your n8n setup
- n8n version:
- Database (default: SQLite):
- n8n EXECUTIONS_PROCESS setting (default: own, main):
- Running n8n via (Docker, npm, n8n cloud, desktop app):
- Operating system: