POST /api/v2/flows/executions returning 400 Bad Request with valid payload

NICE CXone API & Integrations
1

Quick question about triggering Architect flows via REST from a Chrome extension.

I am building a client-side integration that launches a flow based on user context. The documentation implies a simple POST, but I keep hitting a wall. My code sends a JSON body with the flow ID and initial data, yet the server rejects it immediately. Here is the setup.

Endpoint: POST /api/v2/flows/executions
Headers:

  • Content-Type: application/json
  • Authorization: Bearer <token>

Payload:

{
 "flowId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
 "initialData": {
 "contactType": "Voice",
 "customerNumber": "+15550199888"
 }
}

Response: 400 Bad Request with no helpful error message in the body.

I have verified the token has admin:flow:execute permissions. The flow ID exists and is published. I am not using the SDK here, just raw fetch. Am I missing a required field in the initialData schema or is this a known quirk with external triggers?

2

You need to align the request structure with the Genesys Cloud Execution API schema, which diverges significantly from standard REST patterns. My experience migrating Twilio Studio logic to Architect highlights these common pitfalls.

  • Payload Structure: The body must be a JSON object containing a flowId string and a data object. Do not send flat key-value pairs at the root level. The data object holds your initial variables.
  • Content-Type: Ensure Content-Type: application/json is set. The API rejects requests with incorrect or missing MIME types immediately.
  • Authentication: Use a valid OAuth2 Bearer token with the flow:execute scope. Guest tokens often fail here due to permission restrictions.
  • Flow Status: Verify the flow is published. Draft flows cannot be executed via this endpoint.

Here is the correct curl syntax for testing:

curl -X POST https://api.mypurecloud.com/api/v2/flows/executions \
 -H "Authorization: Bearer <TOKEN>" \
 -H "Content-Type: application/json" \
 -d '{
 "flowId": "your-flow-id",
 "data": {
 "userContext": "extension_trigger",
 "priority": 1
 }
 }'

This mirrors the sub-flow invocation pattern in Twilio but requires strict JSON adherence.

3

What’s probably happening here is that a mismatch between your payload structure and the strict schema enforced by the Genesys Cloud platform. While the documentation is helpful, the API parser is unforgiving about nesting. Based on my experience building CLI wrappers with Typer, I see this often when developers flatten the JSON object.

  • Ensure your JSON body strictly follows the ExecutionCreateRequest schema. The root object must contain flowId and data. Do not send variables at the root level.
  • Verify your Content-Type header is exactly application/json. I have seen Chrome extensions default to text/plain which triggers a 400.
  • Check your OAuth token scope. You need flow:execute permission. If your token is missing this, the API might return a misleading 400 instead of a 401.

Here is the minimal working payload structure I use in my Python SDK tests:

{
 "flowId": "your-flow-uuid-here",
 "data": {
 "customVar1": "value1",
 "userId": "12345"
 }
}

Double-check that flowId is a valid UUID string. If you are still stuck, print the raw request body before sending to ensure no serialization errors are occurring in the Chrome extension context.

4

The wrapper object is non-negotiable. GC’s parser expects flowId and data at the root, not flat keys. See the schema spec here: https://support.genesys.cloud/hc/en-us/articles/4408864945651

5

TL;DR: The 400 error is likely caused by missing required scopes or an incorrect Content-Type header, not just the payload structure.

Check your Authorization header and the specific OAuth scopes attached to your access token. The /api/v2/flows/executions endpoint requires flow:execution:write. If your Chrome extension is using a public client ID without proper PKCE flow validation, the token might lack this specific scope, resulting in a silent 400 or 403 depending on the gateway configuration.

Also, verify that Content-Type: application/json is explicitly set. The Genesys Cloud API parser does not infer JSON from the body content alone. If the header is missing or set to text/plain, the deserializer fails before schema validation occurs.

Here is a minimal working fetch example to isolate the issue:

fetch('https://api.mypurecloud.com/api/v2/flows/executions', {
 method: 'POST',
 headers: {
 'Authorization': `Bearer ${accessToken}`,
 'Content-Type': 'application/json'
 },
 body: JSON.stringify({
 flowId: 'your-flow-id-here',
 data: {
 // initial variables
 }
 })
})

Ensure the token is valid and has the correct scope.