WebRef (paid)

Add a duration to an instant and get the result, in UTC and in Tehran local time. Use it for a TTL, a lock expiry, or a token lifetime. ($0.003 per call)

Count the business days between two dates, excluding weekends. Use it to turn a calendar deadline into a working-day deadline. Public holidays are not excluded, so the count is an upper bound. ($0.005 per call)

Check whether a Content-Type header matches what an endpoint kind expects, and say what to send instead when it does not. ($0.003 per call)

Convert a duration between units and get it in plain language. Use it to express a timeout in the unit the caller asked for, or to check whether a limit is seconds, minutes or milliseconds. ($0.003 per call)

Describe an instant: its date, weekday and time in UTC and in Tehran local time (UTC+03:30), plus the Unix timestamp. Use it when a response carries a timestamp and the local date matters. ($0.003 per call)

Describe an HTTP method: whether it is safe, whether it is idempotent, whether it carries a body, and what it is for. ($0.003 per call)

Look up an HTTP status code: what it means, what the client must do, whether it is retryable, whether it is safe to replay, the defining RFC and the common causes. ($0.003 per call)

List or search MIME types by top-level type or by keyword, for example image types or anything to do with calendars. ($0.003 per call)

Look up a MIME type by full type or by file extension: the top-level type, what it is for, and the usual file extension. ($0.003 per call)

Decide how a client should react to a status code: retry with backoff, check the outcome before retrying, or do not retry. Includes a suggested backoff schedule. ($0.005 per call)

Find the HTTP status code that matches a described situation, when the code is not known in advance — for example 'the caller is being rate limited' or 'upstream returned garbage'. ($0.005 per call)

How much time is between two instants: the direction, the total in every unit, and a day/hour/minute/second breakdown. Use it to compute a retry delay, a rate-limit reset, or whether a deadline has passed. ($0.003 per call)

Convert between a date and a Unix timestamp, in either direction. Use it when a payload carries one and the other is needed. ($0.003 per call)

Which day of the week a date falls on, and whether it is a business day. Use it before scheduling work or setting a deadline that lands on a weekend. ($0.003 per call)