# Market Calendar API – OPEX Calendar

> Market Calendar API – OPEX Calendar is a paid API for AI agents from market-calendar-api.onrender.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).

Returns all monthly options expiration dates for a given year across US equity options, VIX, and Eurex, with holiday adjustments and triple witching flags.

## Facts

- Endpoint: GET https://market-calendar-api.onrender.com/v1/opex-calendar?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/market-calendar-api-opex-calendar-29c24add
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_t4gCyvi0lVHNeTtdeILBQ

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 market-calendar-api-opex-calendar-29c24add
```

Example prompt: Can you pull up all the monthly options expiration dates for 2025 across US equities, VIX, and Eurex, and flag which ones are triple witching?

## When to prefer this

Use this endpoint when you need a full annual schedule of monthly options expiration dates — especially when you require triple witching flags or need to distinguish between US equity, VIX, and Eurex venues, and holiday adjustments matter. Prefer this over general financial calendar APIs when OPEX-specific data with venue segmentation is the primary need.

## Known failure modes

- Missing required 'year' parameter returns a validation error
- Invalid or unsupported year value may return an empty result or error
- Invalid 'venue' value outside the allowed enum (all/us/vix/eurex) may return an error or be ignored
- Service on render.com free tier may have cold-start latency or downtime
- Payment failure (x402) blocks the request before reaching the calendar logic

## How this service works

Returns all monthly options expiration dates of a year for US equity options, VIX and Eurex, holiday-adjusted, with triple witching flags.

## Output

A structured list of monthly options expiration dates for the requested year and venue (US equity options, VIX, Eurex, or all), each entry holiday-adjusted and annotated with a boolean flag indicating whether it is a triple witching date.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "year"
     ],
     "properties": {
      "year": {
       "type": "string",
       "description": "Year, e.g. 2027"
      },
      "venue": {
       "type": "string",
       "description": "all, us, vix or eurex"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/market-calendar-api-opex-calendar-29c24add/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market-calendar-api.onrender.com](https://www.zero.xyz/host/market-calendar-api.onrender.com/llms.txt)