# Cron Expression Parser & Explainer

> Cron Expression Parser & Explainer is a paid API for AI agents from x402-deployer.x402-deployer.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Parses a cron expression or macro and returns a plain-English explanation, frequency bucket, validation result, and runs-per-day estimate.

## Facts

- Endpoint: POST https://x402-deployer.x402-deployer.workers.dev/cron-explain
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-1cb27f6a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ey3Bj2kICoIAfpA2_2xU_

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 x402-deployer-x402-deployer-workers-dev-1cb27f6a -d '<json body>'
```

Example prompt: Can you explain what the cron expression '0 9 * * 1-5' means in plain English, tell me how many times per day it runs, and confirm whether it's valid?

## When to prefer this

Use this endpoint when you need to explain, validate, or summarize a cron expression for a human audience, when building scheduling UIs that need human-readable cadence labels, or when verifying that a cron string is syntactically correct before deploying it. Prefer this over a general-purpose LLM explanation when you need a structured, deterministic result including the runs-per-day figure and frequency bucket.

## Known failure modes

- Invalid cron expression syntax returns a validation error with details
- Unsupported field count (e.g. fewer than 5 or more than 7 fields) may return a parse error
- Unrecognized macro strings return a validation failure
- Empty or missing input body returns a 400-level error

## How this service works

Cron expression parser. Takes a 5/6/7-field cron expression or @yearly/@monthly/@weekly/@daily/@hourly macro and returns a plain-English explanation, frequency bucket, validation result, and a runs-per-day estimate. Useful for explaining a schedule to a human, validating a cron string, or generating a cadence summary.

## Output

Returns a plain-English description of the schedule, a frequency bucket (e.g. 'daily', 'weekly', 'hourly'), a boolean/message indicating whether the cron expression is valid, and a numeric estimate of how many times per day the schedule fires.

## Example request

```json
{
 "expression": "0 9 * * 1-5"
}
```

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "properties": {
      "expression": {
       "type": "string",
       "description": "Cron expression (5, 6, or 7 fields) or macro like @daily. Max 500 chars."
      },
      "timezone": {
       "type": "string",
       "description": "IANA timezone name for the explanation, e.g. 'America/New_York'. Optional, default UTC."
      }
     },
     "required": [
      "expression"
     ]
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "explanation": {
       "type": "string"
      },
      "frequency": {
       "type": "string"
      }
     }
    }
   },
   "required": [
    "type"
   ]
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-1cb27f6a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-deployer.x402-deployer.workers.dev](https://www.zero.xyz/host/x402-deployer.x402-deployer.workers.dev/llms.txt)