API call errors - tags and workflow execution

[salacoste]

Bug Description

1. Tag Update Conflict (409)

Endpoint: PUT /api/v1/tags/{id}

Request:

// Update existing tag with the same name
await axios.put(
  'https://n8n-instance.com/api/v1/tags/12345',
  { name: "Existing Tag Name" },
  { headers: { 'X-N8N-API-KEY': 'api_key_here' } }
);

Actual Response:

Status: 409

  "code": 409,
  "message": "Tag with this name already exists"
}

Expected: Status 200 OK with updated tag data

2. Workflow Activation Without Valid Trigger (400) Endpoint: POST /api/v1/workflows/{id}/activate Request:

// Create workflow with manualTrigger
const workflow = {
  name: "Test Workflow",
  nodes: [
    {
      "id": "node_1",
      "name": "Manual Trigger",
      "type": "n8n-nodes-base.manualTrigger",
      "parameters": {},
      "position": [100, 300]
    },
    // Other nodes...
  ],
  "connections": {
    // Connections...
  }
};

// Create then activate
const createResponse = await axios.post(
  'https://n8n-instance.com/api/v1/workflows',
  workflow,
  { headers: { 'X-N8N-API-KEY': 'api_key_here' } }
);

await axios.post(
  `https://n8n-instance.com/api/v1/workflows/${createResponse.data.id}/activate`,
  {},
  { headers: { 'X-N8N-API-KEY': 'api_key_here' } }
);

Actual Response:

Status: 400
{
  "code": 400,
  "message": "Workflow has no node to start the workflow - at least one trigger, poller or webhook node is required"
}

3. Execution Failures for Webhook and Manual Triggers Endpoint: POST /api/v1/workflows/{id}/run Request:

// Execute workflow with webhook or manual trigger
await axios.post(
  'https://n8n-instance.com/api/v1/workflows/12345/run',
  {},
  { headers: { 'X-N8N-API-KEY': 'api_key_here' } }
);

Actual Response (webhook):

Status: 404
{
  "code": 404,
  "message": "Not Found"
}

Response:

Status: 404
{
  "code": 404,
  "message": "Not Found"
}

Actual Response (manualTrigger): No error, but execution does not properly activate the trigger Expected: Status 200 OK with successful execution for all trigger types

n8n Version Information API Version: 1.82.3

• Database (default: SQLite): mysql
• n8n EXECUTIONS_PROCESS setting (default: own, main): default
• Running n8n via (Docker, npm, n8n cloud, desktop app): docker
• Operating system: ubuntu

To Reproduce

execute api calls

await axios.put( 'https://n8n-instance.com/api/v1/tags/12345', { name: "Existing Tag Name" }, { headers: { 'X-N8N-API-KEY': 'api_key_here' } } );

const workflow = { name: "Test Workflow", nodes: [ { "id": "node_1", "name": "Manual Trigger", "type": "n8n-nodes-base.manualTrigger", "parameters": {}, "position": [100, 300] }, // Other nodes... ], "connections": { // Connections... } };

// Create then activate const createResponse = await axios.post( 'https://n8n-instance.com/api/v1/workflows', workflow, { headers: { 'X-N8N-API-KEY': 'api_key_here' } } );

await axios.post( https://n8n-instance.com/api/v1/workflows/${createResponse.data.id}/activate, {}, { headers: { 'X-N8N-API-KEY': 'api_key_here' } } );

Expected behavior

Expected: Status 200 OK with successful execution for all trigger types

Operating System

Ubuntu

n8n Version

1.83.2

Node.js Version

20.18

Database

MySQL

Execution mode

main (default)

[Joffcom]

Hey @salacoste,

We have created an internal ticket to look into this which we will be tracking as "GHC-1248"

[salacoste]

appreciate it so much, i have been doing the MCP workflow server for n8n and found these uncertainties compared to the one that the docs say. Possibly I'm wrong but when I missed or misinterpreted the docs and request structure, let me know.

[MarcL]

Hey @salacoste,

I've just tried to update tags and I have no problem using Insomnia (HTTP client) on my local environment:

Tag Update

GET request to get all tags before:

http://localhost:5678/api/v1/tags

PUT request to update the tag:

http://localhost:5678/api/v1/tags/WF2RfTaYnoQbhrRX

{
	"name": "newTagName"
}

200 response

GET request to get all tags after with the tag updated:

http://localhost:5678/api/v1/tags

You should be able to update the tag name repeatedly to the same name and still get a 200. Unless there's a DB error, I don't think you would receive a 409:

https://github.com/n8n-io/n8n/blob/61957899e1ca9c013dbd0c3385f9484d724df3a0/packages/cli/src/public-api/v1/handlers/tags/tags.handler.ts#L44-L49

Can you give me any more details for recreating this?

Workflow activation

If you don't have a valid trigger that can be executed, you'd expect to get a 400 response. In my example I have a manual trigger so it can't be activated.

400 response

{
	"message": "Workflow \"My workflow 2\" (ID: 100Vv1Q5w6latF5K) has no node to start the workflow - at least one trigger, poller or webhook node is required"
}

If you change it to a scheduled trigger like this, then you'll get a 200 response:

{
	"createdAt": "2025-04-08T12:49:38.542Z",
	"updatedAt": "2025-04-10T15:30:05.000Z",
	"id": "100Vv1Q5w6latF5K",
	"name": "My workflow 2",
	"active": true,
	"nodes": [
		{
			"parameters": {
				"assignments": {
					"assignments": [
						{
							"id": "3a40d9f2-0eed-4a92-9287-9d6ec9ce90e8",
							"name": "message",
							"value": "hello there",
							"type": "string"
						}
					]
				},
				"options": {}
			},
			"type": "n8n-nodes-base.set",
			"typeVersion": 3.4,
			"position": [
				220,
				0
			],
			"id": "1fcb0721-0fc7-44df-8930-626afa77c1c6",
			"name": "Edit Fields1"
		},
...

Running a workflow

I don't think we expose the /workflows/:workflowId/run endpoint via the public API. This will be why you're getting a 404.

https://github.com/n8n-io/n8n/blob/c89010871d28e2cc4d5807fb7b3aa29968a0364c/packages/cli/src/public-api/v1/handlers/workflows/spec/paths/workflows.id.yml

[MarcL]

Hi @salacoste

We haven’t heard back for a while so we’re going to close this for now.

If you’re still running into the issue, or have more details to share, feel free to reopen it or create a new one.

Thanks!