# Register External Webhook Source (inbox.withzero.xyz)

> Register External Webhook Source (inbox.withzero.xyz) is a free API for AI agents from inbox.withzero.xyz, Free, status unknown (last checked 2026-09-15).

Registers an external webhook source (GitHub, Stripe, or generic) and returns the inbound URL and HMAC secret to configure in the external system.

## Facts

- Endpoint: POST https://inbox.withzero.xyz/api/v1/connections
- Price: Free
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 3
- Provider: inbox.withzero.xyz
- Website: https://inbox.withzero.xyz
- Canonical page: https://www.zero.xyz/c/inbox-withzero-xyz-register-external-webhook-source-inbox-withzero-xyz-adfc4c4e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DOQQUsczQIuxnQjkfDurH

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability inbox-withzero-xyz-register-external-webhook-source-inbox-withzero-xyz-adfc4c4e -d '<json body>'
```

Example prompt: Register a new GitHub webhook source called 'my-repo-events' in my inbox so I can paste the returned inbound URL into my GitHub repo settings — use the github source type and I'll provide my own secret 'gh-secret-abc123xyz'.

## When to prefer this

Use this endpoint when you need to receive events pushed by an external system (GitHub, Stripe, or any HTTP webhook source) into your agent's durable inbox. This is the first step before you can drain those events; choose the sourceType matching your provider to get correct HMAC signature verification and payload normalization.

## Known failure modes

- Missing required fields (name or sourceType) returns 400 validation error
- Invalid sourceType value (not github/stripe/generic) returns 400
- Secret too short (under 8 chars) or too long (over 256 chars) returns 400
- Unauthorized request (missing or invalid signed proof credential) returns 401
- Duplicate or conflicting connection name may return 409

## How this service works

Register an external webhook source; returns its inbound URL + secret. 📖 Full guide: https://inbox.withzero.xyz/llms.txt

## Output

Returns a JSON object with the connection ID, human label, sourceType, the inbound webhook URL to paste into the external system, the HMAC signing secret (shown only once), and a createdAt timestamp.

## Example request

```json
{
 "name": "test-generic-webhook",
 "sourceType": "generic"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "name",
  "sourceType"
 ],
 "properties": {
  "name": {
   "type": "string",
   "maxLength": 128,
   "minLength": 1,
   "description": "Human label for this source."
  },
  "secret": {
   "type": "string",
   "maxLength": 256,
   "minLength": 8,
   "description": "HMAC secret. For github/stripe paste the provider secret; omit for generic to auto-generate."
  },
  "sourceType": {
   "enum": [
    "github",
    "stripe",
    "generic"
   ],
   "type": "string",
   "description": "Signature scheme + payload normalizer."
  }
 },
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "id",
  "name",
  "sourceType",
  "url",
  "secret",
  "createdAt"
 ],
 "properties": {
  "id": {
   "type": "string"
  },
  "url": {
   "type": "string",
   "description": "Inbound webhook URL to configure in the external system."
  },
  "name": {
   "type": "string"
  },
  "secret": {
   "type": "string",
   "description": "HMAC secret (shown once). Configure the external system to sign with it."
  },
  "createdAt": {
   "type": "string"
  },
  "sourceType": {
   "type": "string"
  }
 },
 "additionalProperties": false
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/inbox-withzero-xyz-register-external-webhook-source-inbox-withzero-xyz-adfc4c4e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from inbox.withzero.xyz](https://www.zero.xyz/host/inbox.withzero.xyz/llms.txt)