WorkdayAPI

Business-day calculator

Add working days or count working days between two dates, skipping weekends and public holidays. 29 countries, years 2020-2035. Plain calendar dates, no time zones.

Public holidays

Pick a country and date.

Use it from code

curl "https://workdayapi.mike-tusa.workers.dev/v1/add?date=2026-10-05&days=10&country=US"
curl "https://workdayapi.mike-tusa.workers.dev/v1/is-business-day?date=2026-12-26&country=GB"
curl "https://workdayapi.mike-tusa.workers.dev/v1/between?from=2026-12-01&to=2026-12-31&country=FR"

Free: 1,000 API calls a month with a free key. See the API docs.

For AI agents (MCP)

WorkdayAPI is also a remote Model Context Protocol (MCP) server with five read-only tools: get_holidays, is_business_day, add_business_days, business_days_between and list_countries. Most MCP clients accept this config; some use a different format (for example, VS Code uses a servers key). Clients with a settings screen just need the URL https://workdayapi.mike-tusa.workers.dev/mcp. Same limits and free keys as the JSON API.

{ "mcpServers": { "workdayapi": { "type": "http", "url": "https://workdayapi.mike-tusa.workers.dev/mcp" } } }

Machine-readable docs: llms.txt ยท OpenAPI 3.1 spec