# Cron Translator

> Explain any cron expression in plain English, see the next run times in any timezone, and catch the gotchas that make schedules misfire: day-of-month/day-of-week OR semantics, steps that do not divide evenly, impossible dates, and daylight-saving shifts.

Three surfaces over one engine: an HTML page for people, a JSON API, and an MCP
server. All three return the same answers — the engine is a single pure
function and the surfaces are thin wrappers over it.

**What this is not:** Does not run, install, or manage scheduled jobs. Does not support Quartz extensions (L, W, #, ?) beyond detecting and reporting them.

Agent traffic is welcome and unmetered up to 250 calls per UTC
day per caller. Past that, endpoints return HTTP 402 with x402 payment
requirements ($0.001 per call, USDC on Base). Content is identical
for agents and people; only the representation differs.

## Agent endpoints

- [MCP server](https://crontoenglish.com/api/mcp): Streamable HTTP. Tools: explain_cron, next_cron_runs, build_cron.
- [OpenAPI document](https://crontoenglish.com/.well-known/openapi.json): Full machine-readable API description.
- [Explain a cron expression](https://crontoenglish.com/api/v1/explain?expression=0%209%20*%20*%201-5): English description, field breakdown, warnings, next run times.
- [Next run times](https://crontoenglish.com/api/v1/next-runs?expression=0%209%20*%20*%201-5): Upcoming runs only, ISO 8601 plus local wall-clock.
- [Build from English](https://crontoenglish.com/api/v1/build?phrase=every%20weekday%20at%209am): Rule-based English-to-cron. Refuses phrases outside its grammar rather than guessing.
- [Full documentation](https://crontoenglish.com/llms-full.txt): Complete docs with worked examples, inline.
- [Changelog](https://crontoenglish.com/changelog.md): Breaking changes and additions.

## Markdown representations

Every page is available as markdown at the same canonical URL. Send
`Accept: text/markdown` or append `?format=md`. Responses set
`Vary: Accept`. Do not parse the HTML.

## Docs

- [Documentation and MCP setup](https://crontoenglish.com/docs): Copy-paste MCP config for Claude Code, Claude Desktop, and Cursor, plus curl examples.

## Common schedules

- [* * * * *](https://crontoenglish.com/cron/every-minute): Cron for every minute
- [*/2 * * * *](https://crontoenglish.com/cron/every-2-minutes): Cron for every 2 minutes
- [*/5 * * * *](https://crontoenglish.com/cron/every-5-minutes): Cron for every 5 minutes
- [*/10 * * * *](https://crontoenglish.com/cron/every-10-minutes): Cron for every 10 minutes
- [*/15 * * * *](https://crontoenglish.com/cron/every-15-minutes): Cron for every 15 minutes
- [*/20 * * * *](https://crontoenglish.com/cron/every-20-minutes): Cron for every 20 minutes
- [*/30 * * * *](https://crontoenglish.com/cron/every-30-minutes): Cron for every 30 minutes
- [*/45 * * * *](https://crontoenglish.com/cron/every-45-minutes): Cron for every 45 minutes
- [0 * * * *](https://crontoenglish.com/cron/every-hour): Cron for every hour
- [0 */2 * * *](https://crontoenglish.com/cron/every-2-hours): Cron for every 2 hours
- [0 */3 * * *](https://crontoenglish.com/cron/every-3-hours): Cron for every 3 hours
- [0 */4 * * *](https://crontoenglish.com/cron/every-4-hours): Cron for every 4 hours
- [0 */6 * * *](https://crontoenglish.com/cron/every-6-hours): Cron for every 6 hours
- [0 */8 * * *](https://crontoenglish.com/cron/every-8-hours): Cron for every 8 hours
- [0 */12 * * *](https://crontoenglish.com/cron/every-12-hours): Cron for every 12 hours
- [0 */5 * * *](https://crontoenglish.com/cron/every-5-hours): Cron for every 5 hours
- [0 0 * * *](https://crontoenglish.com/cron/every-day-at-midnight): Cron for every day at midnight
- [0 12 * * *](https://crontoenglish.com/cron/every-day-at-noon): Cron for every day at noon
- [0 9 * * *](https://crontoenglish.com/cron/every-day-at-9am): Cron for every day at 9am
- [0 6 * * *](https://crontoenglish.com/cron/every-day-at-6am): Cron for every day at 6am
- [0 17 * * *](https://crontoenglish.com/cron/every-day-at-5pm): Cron for every day at 5pm
- [0 23 * * *](https://crontoenglish.com/cron/every-day-at-11pm): Cron for every day at 11pm
- [0 0,12 * * *](https://crontoenglish.com/cron/twice-a-day): Cron for twice a day
- [0 9 * * 1-5](https://crontoenglish.com/cron/every-weekday-at-9am): Cron for every weekday at 9am
- [0 0 * * 1-5](https://crontoenglish.com/cron/every-weekday): Cron for every weekday
- [0 9-17 * * 1-5](https://crontoenglish.com/cron/business-hours-every-hour): Cron for every hour during business hours
- [*/15 9-17 * * 1-5](https://crontoenglish.com/cron/every-15-minutes-during-business-hours): Cron for every 15 minutes during business hours
- [0 0 * * 0,6](https://crontoenglish.com/cron/every-weekend): Cron for every weekend day
- [0 9 * * 1](https://crontoenglish.com/cron/every-monday-at-9am): Cron for every Monday at 9am
- [0 17 * * 5](https://crontoenglish.com/cron/every-friday-at-5pm): Cron for every Friday at 5pm
- [0 0 * * 0](https://crontoenglish.com/cron/every-sunday-at-midnight): Cron for every Sunday at midnight
- [0 2 * * 6](https://crontoenglish.com/cron/every-saturday-at-2am): Cron for every Saturday at 2am
- [0 0 1 * *](https://crontoenglish.com/cron/first-of-the-month): Cron for the first of every month
- [0 0 15 * *](https://crontoenglish.com/cron/fifteenth-of-the-month): Cron for the 15th of every month
- [0 0 28-31 * *](https://crontoenglish.com/cron/last-day-of-the-month): Cron for the last day of the month
- [0 0 1 1,4,7,10 *](https://crontoenglish.com/cron/every-quarter): Cron for every quarter
- [0 0 1 1 *](https://crontoenglish.com/cron/every-year-on-january-1): Cron for once a year on January 1
- [0 9 1-7 * 1](https://crontoenglish.com/cron/first-monday-of-the-month): Cron for the first Monday of the month