Glossary term
What is RFC 3339 (RFC 3339 date and time)?
RFC 3339 stands for RFC 3339 date and time.
A standard text format for dates and times, such as 2026-03-08T14:30:00Z, where the Z means UTC.
Learn it properly · API DesignLesson 2: Request and Response Design: JSON Shapes, Errors and ValidationConsistent JSON, naming, dates and money, one error format (RFC 9457 problem details), validation with clear messages, and what never to return.