What is the regex pattern for iso 8601 datetime?

The regex pattern for iso 8601 datetime is: ^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+-]\d{2}:\d{2})$.

How does the iso 8601 datetime regex work?

\d{4}-\d{2}-\d{2}: Date in YYYY-MM-DD format. T: Literal T separator between date and time. \d{2}:\d{2}:\d{2}: Time in HH:MM:SS format. (?:\.\d+)?: Optional fractional seconds. (?:Z|[+-]\d{2}:\d{2}): Timezone: Z (UTC) or offset like +05:30.

Regex for ISO 8601 DateTime

Matches ISO 8601 datetime strings with timezone. Example: 2026-03-15T14:30:00Z or 2026-03-15T14:30:00+05:30.

Pattern

/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+-]\d{2}:\d{2})$/

Pattern Breakdown

Token	Explanation
\d{4}-\d{2}-\d{2}	Date in YYYY-MM-DD format
T	Literal T separator between date and time
\d{2}:\d{2}:\d{2}	Time in HH:MM:SS format
(?:\.\d+)?	Optional fractional seconds
(?:Z\|[+-]\d{2}:\d{2})	Timezone: Z (UTC) or offset like +05:30

Test Examples

Input	Match?
2026-03-15T14:30:00Z	Match
2026-03-15T14:30:00.123Z	Match
2026-03-15T14:30:00+05:30	Match
2026-03-15 14:30:00	No match
2026-03-15	No match

Common Use Cases

API timestamp validation
Log timestamp parsing
Date interchange format verification

Variations

^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z$

UTC only (no offset)

Other Regex Patterns

Email Address US Phone Number International Phone Number URL IPv4 Address IPv6 Address Date (MM/DD/YYYY)Date (ISO 8601 YYYY-MM-DD)Time (HH:MM, 24-hour)Credit Card Number US Social Security Number US ZIP Code

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