Trying to authenticate to a local n8n REST API (self-hosted CE on Docker Desktop / Windows 11) — 401 Unauthorized returned for both an env-set API key and UI-created API keys; need help diagnosing why

[PFL]

Describe the problem/error/question

I have a self-hosted n8n Community Edition instance running on Windows 11 via Docker Desktop (plain docker run). My end goal is to build a Custom GPT (“N8NGPT”) that can interact with my local n8n via the REST API (list workflows, create workflows, patch/activate, etc.) so I can automate deployment and editing of workflows programmatically.

Despite many attempts and different authentication approaches, every request to GET /rest/workflows returns:

{“status”:“error”,“message”:“Unauthorized”}

I have tried:

• Starting n8n with an environment API key (N8N_API_KEY) passed via docker run.

• Creating an API key in the n8n UI (Settings → n8n API) and using that UI key in requests.

• Testing with curl.exe on Windows, Invoke-RestMethod in PowerShell, and from a Linux curl container (curlimages/curl) to avoid Windows client quirks.

• Running without mounting any host volume (ephemeral container) to eliminate permission issues.

All attempts return HTTP 401. I’ve inspected docker logs and the instance shows normal startup and DB migrations, and netstat indicates port 5678 is listening. I’m stuck and asking whether this is a misconfiguration on my side, a Windows/Docker Desktop networking/header stripping problem, or a bug/behavior in n8n v1.112.4 where env/static keys and UI keys conflict.

What is the error message (if any)?

Primary API error (every request to /rest/* when providing a key):
{"status":"error","message":"Unauthorized"} (HTTP/1.1 401 Unauthorized)

Please share your workflow (if any)
None to share — I haven’t been able to create workflows via the API because POST /rest/workflows also returns 401. I did prepare an example “Hello World” JSON for testing, but import attempts were blocked by the auth failure.

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

• 1. n8n version: 1.112.4 (from container logs: Version: 1.112.4)

  2. Database: Default SQLite (the container ran migrations on startup; no external DB configured).

  3. n8n EXECUTIONS_PROCESS setting: Default (no custom EXECUTIONS_PROCESS / N8N_RUNNERS_ENABLED set — running with default execution process).

  4. Running n8n via: Docker (plain docker run under Docker Desktop on Windows 11).

  5. Operating system (host): Windows 11 (Docker Desktop).

     MORE INFO:

     Hypothesized that the N8N_API_KEY env var vs UI key behavior might be clashing — recommended two safe paths:

     1. Start container without N8N_API_KEY env var and then create/use UI API key in the UI (recommended if you want UI-managed JWT-like keys).

     2. Or keep N8N_API_KEY set and use that literal value as your API key for programmatic access (you lose per-key management via UI).

        COMMANDS/OUTPUTS:

        1. Test API from host using Windows curl

        PS C:\Users\Suhaib Ahmed> curl.exe -H "X-N8N-API-KEY: firstkey123" http://localhost:5678/rest/workflows
        

Output:

{"status":"error","message":"Unauthorized"}

2. Verbose Windows curl test

   PS C:\Users\Suhaib Ahmed> curl.exe -v -H "X-N8N-API-KEY: firstkey123" "http://localhost:5678/rest/workflows"
   

   Output (important parts):

   > GET /rest/workflows HTTP/1.1
   > Host: localhost:5678
   > X-N8N-API-KEY: firstkey123
   < HTTP/1.1 401 Unauthorized
   {"status":"error","message":"Unauthorized"}
   

3. Run Linux curl inside container (curlimages/curl)

   PS C:\Users\Suhaib Ahmed> docker run --rm curlimages/curl:latest -v -H "X-N8N-API-KEY: firstkey123" http://host.docker.internal:5678/rest/workflows
   

   Output (important parts):

   * Established connection to host.docker.internal (192.168.65.254 port 5678)
   > GET /rest/workflows HTTP/1.1
   > X-N8N-API-KEY: firstkey123
   < HTTP/1.1 401 Unauthorized
   {"status":"error","message":"Unauthorized"}
   

4. Inspected env var inside container

   PS C:\Users\Suhaib Ahmed> docker exec -it n8n printenv | findstr N8N_API_KEY
   

Output:

N8N_API_KEY=firstkey123

5. Tried curl inside container (failed: no curl installed)

   PS C:\Users\Suhaib Ahmed> docker exec -it n8n curl -H "X-N8N-API-KEY: firstkey123" http://localhost:5678/rest/workflows
   

Output:

OCI runtime exec failed: exec failed: unable to start container process: exec: "curl": executable file not found in $PATH: unknown

6. Tested with PowerShell Invoke-RestMethod

   PS C:\Users\Suhaib Ahmed> Invoke-RestMethod -Uri "http://localhost:5678/rest/workflows" `
      -Method Get `
      -Headers @{"X-N8N-API-KEY"="firstkey123"} `
      -Proxy $null -Verbose
   

Output:

VERBOSE: GET with 0-byte payload
Invoke-RestMethod : {"status":"error","message":"Unauthorized"}
...

7. A. Used JWT-style API key (from UI)

   PS C:\Users\Suhaib Ahmed> docker run --rm curlimages/curl:latest -v -H "X-N8N-API-KEY: <REDACTED_UI_KEY>" http://host.docker.internal:5678/rest/workflows
   

   Output:

   < HTTP/1.1 401 Unauthorized
   {"status":"error","message":"Unauthorized"}
   
   

   PS C:\Users\Suhaib Ahmed> curl.exe -H "X-N8N-API-KEY: <REDACTED_UI_KEY>" "http://localhost:5678/rest/workflows"
   
   

   Output:

   {"status":"error","message":"Unauthorized"}
   
   

8. B. Tried again with new UI key

   PS C:\Users\Suhaib Ahmed> docker run --rm curlimages/curl:latest -v -H "X-N8N-API-KEY: <REDACTED_NEW_UI_KEY>" http://host.docker.internal:5678/rest/workflows
   

   Output:

   < HTTP/1.1 401 Unauthorized
   {"status":"error","message":"Unauthorized"}
   

9. Container logs

   PS C:\Users\User> docker logs n8n
   
   

   Output (important parts):

   Initializing n8n process
   n8n ready on ::, port 5678
   Migrations in progress, please do NOT stop the process.
   ...
   Editor is now accessible via:
   http://localhost:5678
   Owner was set up successfully
   User survey updated successfully
   [license SDK] license successfully activated
   

IN ESSENCE:
I have tried:

• Starting n8n with an environment API key (N8N_API_KEY) passed via docker run.

• Creating an API key in the n8n UI (Settings → n8n API) and using that UI key in requests.

• Testing with curl.exe on Windows, Invoke-RestMethod in PowerShell, and from a Linux curl container (curlimages/curl) to avoid Windows client quirks.

• Running without mounting any host volume (ephemeral container) to eliminate permission issues.

All attempts return HTTP 401

Any help would be massively appreciated , I’ve put in hours to fix this but to no avail