# Changelog State API – Vercel Change History

> Changelog State API – Vercel Change History is a paid API for AI agents from changelog-state-api.replit.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns detected changelog update history (new releases, version changes, breaking signals, etc.) for the Vercel vendor, filterable by change type and date.

## Facts

- Endpoint: GET https://changelog-state-api.replit.app/api/monitors/vercel/changes
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/changelog-state-api-vercel-change-history-b5a0513e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pueEzxVtZQ8BTr9-iqmpp

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 changelog-state-api-vercel-change-history-b5a0513e
```

Example prompt: Can you pull the detected changelog update history for Vercel — show me up to 100 entries and only include breaking_signal changes since 2024-01-01T00:00:00Z?

## When to prefer this

Choose this endpoint when you need a filtered, structured history of detected changelog mutations for Vercel specifically — particularly when you want to isolate breaking signals, version bumps, or new releases over a specific time window. It is ideal for automated monitoring pipelines or agents that need to react to Vercel's changelog changes programmatically.

## Known failure modes

- Invalid or unknown vendor slug returns 404 or empty result set
- Invalid change type enum value returns 400 validation error
- Malformed since date-time format causes 400 parse error
- Limit out of range (below 1 or above 200) triggers schema validation error
- Payment not provided or insufficient USDC balance returns 402
- Service unavailability on Replit hosting returns 503 or timeout

## How this service works

Detected changelog update history for one tracked vendor.

## Output

A JSON array of detected changelog change records for Vercel, each containing a change type (e.g. new_release, version_changed, breaking_signal), detection timestamp, and relevant metadata. Results are filterable by change type and date range, with a configurable limit up to 200 rows.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "slug"
     ],
     "properties": {
      "slug": {
       "type": "string",
       "pattern": "^[a-z0-9][a-z0-9-]*$",
       "maxLength": 64,
       "minLength": 1,
       "description": "Vendor slug, lowercase alphanumeric with dashes."
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "type": {
       "enum": [
        "new_release",
        "version_changed",
        "date_changed",
        "title_changed",
        "breaking_signal"
       ],
       "type": "string",
       "description": "Restrict to a single change type."
      },
      "limit": {
       "type": "integer",
       "default": 50,
       "maximum": 200,
       "minimum": 1,
       "description": "Maximum number of change rows to return."
      },
      "since": {
       "type": "string",
       "format": "date-time",
       "description": "Only return changes detected at or after this instant."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "enum": [
      "json"
     ],
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   },
   "description": "Detected changelog update history (paid)"
  }
 },
 "description": "Call shape for GET /api/monitors/{slug}/changes."
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/changelog-state-api-vercel-change-history-b5a0513e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from changelog-state-api.replit.app](https://www.zero.xyz/host/changelog-state-api.replit.app/llms.txt)