What is Timestamp?
A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day. In computing, timestamps are used to record when data was created, modified, or accessed.
Quick Facts
| Full Name | Computer Timestamp |
|---|---|
| Created | Concept predates digital computing |
| Specification | Official Specification |
How It Works
Timestamps are fundamental to computing, providing a way to track and order events chronologically. They can be represented in various formats including Unix timestamps (seconds since 1970), ISO 8601 strings, or database-specific formats. The precision can vary from seconds to nanoseconds depending on the application. Timestamps are essential for debugging, logging, data synchronization, and ensuring data integrity across distributed systems.
Key Characteristics
- Records the exact moment an event occurred
- Can be represented in multiple formats (Unix, ISO 8601, etc.)
- Precision varies from seconds to nanoseconds
- Essential for chronological ordering of events
- Timezone-aware or UTC-based for consistency
- Used in databases, logs, APIs, and file systems
Common Use Cases
- Logging and debugging applications
- Database record creation and modification tracking
- API request and response timing
- File system metadata (created, modified, accessed times)
- Event ordering in distributed systems
Example
Loading code...Frequently Asked Questions
What is the difference between Unix timestamp in seconds and milliseconds?
Unix timestamp in seconds counts the number of seconds since January 1, 1970 UTC (10 digits, e.g., 1704067200). Millisecond timestamps provide more precision by counting milliseconds (13 digits, e.g., 1704067200000). JavaScript's Date.now() returns milliseconds, while many backend systems use seconds.
How do I handle timezone issues with timestamps?
Always store timestamps in UTC to avoid timezone ambiguity. Convert to local time only when displaying to users. Unix timestamps are inherently timezone-neutral (they represent a specific moment in time). When using ISO 8601 format, always include the timezone offset or use 'Z' for UTC.
What is the Year 2038 problem with Unix timestamps?
32-bit systems store Unix timestamps as signed integers, which will overflow on January 19, 2038 at 03:14:07 UTC. After this point, timestamps will wrap around to negative values representing dates in 1901. Modern 64-bit systems use 64-bit integers, extending the range far into the future.
Which timestamp format should I use for APIs?
ISO 8601 format (e.g., 2024-01-01T00:00:00Z) is recommended for APIs because it is human-readable, includes timezone information, and is widely supported. Unix timestamps are more compact but less readable. Many APIs accept both formats for flexibility.
How do I compare timestamps across different formats?
Convert all timestamps to a common format before comparison. Unix timestamps (in the same unit) can be compared directly as numbers. For ISO 8601 strings, parse them into Date objects first. Always ensure both timestamps are in the same timezone (preferably UTC) before comparing.