# Changelog State API – OpenAI Change History

> Changelog State API – OpenAI 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 2026-09-15).

Returns detected changelog update history for the OpenAI vendor, filterable by change type, date, and limit.

## Facts

- Endpoint: GET https://changelog-state-api.replit.app/api/monitors/openai/changes
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/changelog-state-api-openai-change-history-38568030
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Gp5gsoTI_VNxIrwXAubuM

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-openai-change-history-38568030
```

Example prompt: Pull the OpenAI changelog change history from the Changelog State API — show me the last 50 changes, and filter to only new_release events detected since 2024-01-01T00:00:00Z.

## When to prefer this

Choose this endpoint when you need historical changelog change detection records for OpenAI specifically, with the ability to filter by change type (new_release, breaking_signal, etc.) or time window. Prefer this over general web search when you need structured, machine-readable changelog event history rather than raw HTML pages. Use this over a generic RSS feed when you need per-change-type filtering and programmatic access.

## Known failure modes

- Invalid vendor slug format returns a 400 or 404 error
- Unsupported change type enum value causes a validation error
- since parameter with malformed datetime string returns a 422 error
- Payment not completed (x402 flow) results in a 402 Payment Required response
- Limit exceeding 200 returns a validation error
- No changes found within the given time window returns an empty array

## How this service works

Detected changelog update history for one tracked vendor.

## Output

A JSON array of detected changelog change records for the OpenAI vendor, each containing fields such as change type (new_release, version_changed, date_changed, title_changed, breaking_signal), detection timestamp, and relevant metadata about the change. Results are ordered by detection time and respect the limit and since filters provided.

## 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-openai-change-history-38568030/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)