French business days API for AI agents
Compute French working-day deadlines correctly: this endpoint adds N business days to a date or counts them between two dates, skipping weekends and the 11 French legal public holidays (Code du travail art. L3133-1), with movable feasts (Easter Monday, Ascension, Whit Monday) computed via the Butcher-Meeus algorithm. Both French conventions are supported: jours ouvres (Mon-Fri, default) and jours ouvrables (Mon-Sat). The computation is fully local and deterministic - no upstream API.
It is built for autonomous agents: no account, no API key - the agent pays $0.005 per computation in USDC and gets the end date plus the list of holidays crossed, so a payment-terms or legal-notice deadline is auditable, not a guess.
Endpoint
GET /v1/fr/business-days — $0.005 per call (USDC on Base, x402). Also available as the MCP tool business_days_fr on https://data.greeneris.io/mcp.
Parameters
| Param | Description |
|---|---|
start | ISO date YYYY-MM-DD to add business days to (use with add) |
add | Business days to add, 1-366 (default 1) |
from | ISO range start (use with to, counting mode) |
to | ISO range end, inclusive |
mode | ouvres = Mon-Fri (default), ouvrables = Mon-Sat |
Example
curl -i "https://data.greeneris.io/v1/fr/business-days?start=2026-07-13&add=30"
# HTTP/1.1 402 Payment Required + machine-readable quote
# (any x402 client pays the quote and retries automatically)Response after payment:
{"ok": true, "data": {"mode": "ouvres", "start": "2026-07-13", "business_days_added": 30, "end_date": "2026-08-25", "calendar_days": 43, "holidays_crossed": [{"date": "2026-07-14", "name": "fete_nationale"}, {"date": "2026-08-15", "name": "assomption"}], "source": "Computed locally: French legal holidays (Code du travail L3133-1), Easter via Butcher-Meeus"}}What agents use it for
- Payment terms: turn '30 jours ouvres' on a French invoice into an exact due date
- Legal and HR notice periods: count working days between two dates for compliance checks
- Logistics ETAs: promise delivery dates that skip French holidays like August 15
How payment works
Call the endpoint: you get HTTP 402 with a signed quote (price, receiving address, network). Your agent pays a few tenths of a cent in USDC on Base (gasless, EIP-3009) and retries - one round trip, no account, no API key. Settlement only happens after a successful answer. Full catalog: llms.txt.