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datetime.openverbs.com Add Duration
x402
datetime.openverbs.com Add Duration is a paid API for AI agents from datetime.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).
Adds (or subtracts) an ISO 8601 duration to a start date or datetime, returning the resulting UTC instant with calendar-aware handling of month/year boundaries.
Price / call$0.002
Success—
StatusUnknown
How this service works
Add an ISO 8601 duration to a start date or date-time and return the resulting UTC instant. Calendar-aware: months and years honor month lengths (e.g. Jan 31 + P1M clamps to the last day of February). A negative-signed duration subtracts.
Output
Returns the resulting UTC instant after adding the specified ISO 8601 duration to the start date or datetime. Month and year arithmetic is calendar-aware (e.g., Jan 31 + P1M clamps to Feb 28/29). Negative durations subtract instead of add.
Example use cases
Subscription renewal date calculation
“My subscription started on 2024-03-31 and runs for 1 year — what exact date does it expire? Add P1Y to 2024-03-31 and tell me the resulting date.”
Project deadline offset from kickoff
“Our project kicks off on 2025-02-28 and has a 10-week timeline. What is the deadline date? Add P10W to 2025-02-28.”
Loan maturity date from disbursement
“A loan was disbursed on 2024-11-30 with a 3-month term. What is the maturity date? Add P3M to 2024-11-30, making sure to clamp to the last day of February if needed.”
Technical details
Endpoint
POSThttps://datetime.openverbs.com/v1/addWhen to prefer
Use this endpoint when you need calendar-correct date arithmetic — especially for month or year additions where clamping to valid month-end dates matters (e.g., Jan 31 + 1 month = Feb 28, not March 3). Prefer this over manual arithmetic or generic date libraries when the result must be a precise UTC instant from a structured ISO 8601 duration.
Side effects
- Invalid ISO 8601 date format in 'start' field returns a 400 error
- Invalid ISO 8601 duration format in 'duration' field returns a 400 error
- Date out of representable range returns an error
- Missing required fields 'start' or 'duration' returns a 422 validation error
- Payment not provided or insufficient funds returns a 402 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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