# Cron Expression API (`caulleonard/cron-api`) Actor Validate cron expressions and compute next run times via a simple HTTP API. - **URL**: https://apify.com/caulleonard/cron-api.md - **Developed by:** [Fatih Şahinbaş](https://apify.com/caulleonard) (community) - **Categories:** Developer tools - **Stats:** 1 total users, 0 monthly users, 0.0% runs succeeded, 0 bookmarks - **User rating**: No ratings yet ## Pricing from $1.00 / 1,000 api calls This Actor is paid per event and usage. You are charged both the fixed price for specific events and for Apify platform usage. Learn more: https://docs.apify.com/platform/actors/running/actors-in-store#pay-per-event ## What's an Apify Actor? Actors are a software tools running on the Apify platform, for all kinds of web data extraction and automation use cases. In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours, and optionally produces a well-defined JSON output, datasets with results, or files in key-value store. In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server. Actors are written with capital "A". ## How to integrate an Actor? If asked about integration, you help developers integrate Actors into their projects. You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready. The best way to integrate Actors is as follows. In JavaScript/TypeScript projects, use official [JavaScript/TypeScript client](https://docs.apify.com/api/client/js.md): ```bash npm install apify-client ``` In Python projects, use official [Python client library](https://docs.apify.com/api/client/python.md): ```bash pip install apify-client ``` In shell scripts, use [Apify CLI](https://docs.apify.com/cli/docs.md): ````bash # MacOS / Linux curl -fsSL https://apify.com/install-cli.sh | bash # Windows irm https://apify.com/install-cli.ps1 | iex ```bash In AI frameworks, you might use the [Apify MCP server](https://docs.apify.com/platform/integrations/mcp.md). If your project is in a different language, use the [REST API](https://docs.apify.com/api/v2.md). For usage examples, see the [API](#api) section below. For more details, see Apify documentation as [Markdown index](https://docs.apify.com/llms.txt) and [Markdown full-text](https://docs.apify.com/llms-full.txt). # README ## Cron Expression API — Validate, Describe & Calculate Next Run Times A fast, no-nonsense HTTP API for working with **cron expressions**. Validate crontab syntax, calculate the **next run times**, look up previous runs, and turn any cron schedule into a plain-English description — all through simple GET requests. Stop guessing whether `*/15 9-17 * * 1-5` is correct or when it fires next. This **cron parser API** answers instantly, with full timezone support. ### What it does - ✅ **Validate cron expressions** — catch bad fields, out-of-range values, and wrong field counts with clear per-field error messages. - ⏭️ **Next run times** — compute the upcoming N execution times for any cron schedule, in any IANA timezone. - ⏮️ **Previous run times** — look back at when a schedule last fired. - 💬 **Human-readable descriptions** — convert `0 17 * * 1` into "At 17:00, only on Monday". - 🧩 **One-call parse** — validation, description, and next runs in a single request. ### Who it's for Developers building schedulers, CI/CD pipelines, job queues, dashboards, and admin panels who need to validate crontab input or preview when a cron job will run — without shipping a cron library into every service. Perfect for form validation, "next run" previews in UIs, and documentation tooling. ### Supported syntax - Standard **5-field** cron: `minute hour day-of-month month day-of-week` - **6-field** cron with seconds: `second minute hour day-of-month month day-of-week` - **Macros**: `@yearly` `@annually` `@monthly` `@weekly` `@daily` `@hourly` `@midnight` - **Ranges, lists, steps**: `1-5`, `1,3,5`, `*/15`, `9-17` - **Names**: `sun`, `mon`, `jan`, `feb`, ... - **Extensions**: `L` (last day), `W` (nearest weekday), `#` (nth weekday) — e.g. `0 0 * * 1#2` = second Monday. ### Endpoints All endpoints are **GET** and return JSON. | Endpoint | Purpose | Key params | |----------|---------|------------| | `/validate` | Check if an expression is valid | `expr` | | `/next` | Next N run times | `expr`, `count`, `tz`, `base` | | `/prev` | Previous N run times | `expr`, `count`, `tz`, `base` | | `/describe` | Plain-English description | `expr` | | `/parse` | Validate + describe + next runs in one call | `expr`, `count`, `tz`, `base` | **Parameters** - `expr` *(required)* — the cron expression, e.g. `*/15 9-17 * * 1-5` - `count` — how many run times to return (default `5`, max `100`) - `tz` — IANA timezone (default `UTC`), e.g. `Europe/Istanbul`, `America/New_York` - `base` — ISO 8601 datetime to calculate from (default: now) ### Example Request: ```` GET /parse?expr=0 9 \* \* 1-5\&count=3\&tz=Europe/Istanbul ```` Response: ```json { "valid": true, "normalized": "0 9 * * 1-5", "fields": 5, "description": "At 09:00, Monday through Friday", "tz": "Europe/Istanbul", "next_runs": [ "2026-01-05T09:00:00+03:00", "2026-01-06T09:00:00+03:00", "2026-01-07T09:00:00+03:00" ], "warning": null } ```` Invalid input returns a helpful error: ``` GET /validate?expr=60 * * * * ``` ```json { "valid": false, "normalized": "60 * * * *", "fields": null, "errors": ["minute: '60' out of range 0-59"] } ``` ### How it works The API runs in **Standby mode** — send it HTTP requests directly, no run to start. Under the hood it uses battle-tested cron parsing for accurate scheduling math, adds a strict validation layer for friendly error messages, and computes run times against the timezone you specify. Impossible schedules (like `0 0 30 2 *`, February 30th) are detected and flagged rather than looping forever. ### Tips - Encode spaces in the `expr` query string (`%20`) when testing from the command line. - Use `base` to compute run times from a fixed point instead of "now" — handy for reproducible tests. - Need seconds-level precision? Pass a 6-field expression. - `tz` accepts any IANA name; a wrong name returns a clear `400` error. ### Pricing Pay-per-event: **$0.001 per successful API call**. Readiness/health checks are never charged. No subscription, no minimums — you pay only for the requests you make. # Actor input Schema ## Actor input object example ```json {} ``` # API You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup. ## JavaScript example ```javascript import { ApifyClient } from 'apify-client'; // Initialize the ApifyClient with your Apify API token // Replace the '' with your token const client = new ApifyClient({ token: '', }); // Prepare Actor input const input = {}; // Run the Actor and wait for it to finish const run = await client.actor("caulleonard/cron-api").call(input); // Fetch and print Actor results from the run's dataset (if any) console.log('Results from dataset'); console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`); const { items } = await client.dataset(run.defaultDatasetId).listItems(); items.forEach((item) => { console.dir(item); }); // 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs ``` ## Python example ```python from apify_client import ApifyClient # Initialize the ApifyClient with your Apify API token # Replace '' with your token. client = ApifyClient("") # Prepare the Actor input run_input = {} # Run the Actor and wait for it to finish run = client.actor("caulleonard/cron-api").call(run_input=run_input) # Fetch and print Actor results from the run's dataset (if there are any) print("💾 Check your data here: https://console.apify.com/storage/datasets/" + run["defaultDatasetId"]) for item in client.dataset(run["defaultDatasetId"]).iterate_items(): print(item) # 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start ``` ## CLI example ```bash echo '{}' | apify call caulleonard/cron-api --silent --output-dataset ``` ## MCP server setup ```json { "mcpServers": { "apify": { "command": "npx", "args": [ "mcp-remote", "https://mcp.apify.com/?tools=caulleonard/cron-api", "--header", "Authorization: Bearer " ] } } } ``` ## OpenAPI specification ```json { "openapi": "3.0.1", "info": { "title": "Cron Expression API", "description": "Validate cron expressions and compute next run times via a simple HTTP API.", "version": "0.0", "x-build-id": "Yh9yjWFKxa1Z8aVoU" }, "servers": [ { "url": "https://api.apify.com/v2" } ], "paths": { "/acts/caulleonard~cron-api/run-sync-get-dataset-items": { "post": { "operationId": "run-sync-get-dataset-items-caulleonard-cron-api", "x-openai-isConsequential": false, "summary": "Executes an Actor, waits for its completion, and returns Actor's dataset items in response.", "tags": [ "Run Actor" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/inputSchema" } } } }, "parameters": [ { "name": "token", "in": "query", "required": true, "schema": { "type": "string" }, "description": "Enter your Apify token here" } ], "responses": { "200": { "description": "OK" } } } }, "/acts/caulleonard~cron-api/runs": { "post": { "operationId": "runs-sync-caulleonard-cron-api", "x-openai-isConsequential": false, "summary": "Executes an Actor and returns information about the initiated run in response.", "tags": [ "Run Actor" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/inputSchema" } } } }, "parameters": [ { "name": "token", "in": "query", "required": true, "schema": { "type": "string" }, "description": "Enter your Apify token here" } ], "responses": { "200": { "description": "OK", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/runsResponseSchema" } } } } } } }, "/acts/caulleonard~cron-api/run-sync": { "post": { "operationId": "run-sync-caulleonard-cron-api", "x-openai-isConsequential": false, "summary": "Executes an Actor, waits for completion, and returns the OUTPUT from Key-value store in response.", "tags": [ "Run Actor" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/inputSchema" } } } }, "parameters": [ { "name": "token", "in": "query", "required": true, "schema": { "type": "string" }, "description": "Enter your Apify token here" } ], "responses": { "200": { "description": "OK" } } } } }, "components": { "schemas": { "inputSchema": { "type": "object", "properties": {} }, "runsResponseSchema": { "type": "object", "properties": { "data": { "type": "object", "properties": { "id": { "type": "string" }, "actId": { "type": "string" }, "userId": { "type": "string" }, "startedAt": { "type": "string", "format": "date-time", "example": "2025-01-08T00:00:00.000Z" }, "finishedAt": { "type": "string", "format": "date-time", "example": "2025-01-08T00:00:00.000Z" }, "status": { "type": "string", "example": "READY" }, "meta": { "type": "object", "properties": { "origin": { "type": "string", "example": "API" }, "userAgent": { "type": "string" } } }, "stats": { "type": "object", "properties": { "inputBodyLen": { "type": "integer", "example": 2000 }, "rebootCount": { "type": "integer", "example": 0 }, "restartCount": { "type": "integer", "example": 0 }, "resurrectCount": { "type": "integer", "example": 0 }, "computeUnits": { "type": "integer", "example": 0 } } }, "options": { "type": "object", "properties": { "build": { "type": "string", "example": "latest" }, "timeoutSecs": { "type": "integer", "example": 300 }, "memoryMbytes": { "type": "integer", "example": 1024 }, "diskMbytes": { "type": "integer", "example": 2048 } } }, "buildId": { "type": "string" }, "defaultKeyValueStoreId": { "type": "string" }, "defaultDatasetId": { "type": "string" }, "defaultRequestQueueId": { "type": "string" }, "buildNumber": { "type": "string", "example": "1.0.0" }, "containerUrl": { "type": "string" }, "usage": { "type": "object", "properties": { "ACTOR_COMPUTE_UNITS": { "type": "integer", "example": 0 }, "DATASET_READS": { "type": "integer", "example": 0 }, "DATASET_WRITES": { "type": "integer", "example": 0 }, "KEY_VALUE_STORE_READS": { "type": "integer", "example": 0 }, "KEY_VALUE_STORE_WRITES": { "type": "integer", "example": 1 }, "KEY_VALUE_STORE_LISTS": { "type": "integer", "example": 0 }, "REQUEST_QUEUE_READS": { "type": "integer", "example": 0 }, "REQUEST_QUEUE_WRITES": { "type": "integer", "example": 0 }, "DATA_TRANSFER_INTERNAL_GBYTES": { "type": "integer", "example": 0 }, "DATA_TRANSFER_EXTERNAL_GBYTES": { "type": "integer", "example": 0 }, "PROXY_RESIDENTIAL_TRANSFER_GBYTES": { "type": "integer", "example": 0 }, "PROXY_SERPS": { "type": "integer", "example": 0 } } }, "usageTotalUsd": { "type": "number", "example": 0.00005 }, "usageUsd": { "type": "object", "properties": { "ACTOR_COMPUTE_UNITS": { "type": "integer", "example": 0 }, "DATASET_READS": { "type": "integer", "example": 0 }, "DATASET_WRITES": { "type": "integer", "example": 0 }, "KEY_VALUE_STORE_READS": { "type": "integer", "example": 0 }, "KEY_VALUE_STORE_WRITES": { "type": "number", "example": 0.00005 }, "KEY_VALUE_STORE_LISTS": { "type": "integer", "example": 0 }, "REQUEST_QUEUE_READS": { "type": "integer", "example": 0 }, "REQUEST_QUEUE_WRITES": { "type": "integer", "example": 0 }, "DATA_TRANSFER_INTERNAL_GBYTES": { "type": "integer", "example": 0 }, "DATA_TRANSFER_EXTERNAL_GBYTES": { "type": "integer", "example": 0 }, "PROXY_RESIDENTIAL_TRANSFER_GBYTES": { "type": "integer", "example": 0 }, "PROXY_SERPS": { "type": "integer", "example": 0 } } } } } } } } } } ```