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7/5/2026
Unix Timestamp Cheat Sheet: Convert, Read, and Debug Like a Pro

Unix Timestamp Cheat Sheet: Convert, Read, and Debug Like a Pro

Short summary

Unix timestamps measure seconds or milliseconds since Jan 1, 1970 UTC and are critical for APIs, JWTs, and databases. The most common bug is confusing seconds vs milliseconds—JavaScript uses ms while most backends use seconds. Includes conversion code examples in JavaScript, Python, SQL, Bash, Java, Go, Rust, plus JWT expiration checks and timezone best practices.

  • •Unix timestamps = seconds/milliseconds since Jan 1, 1970 UTC
  • •Most common bug: seconds vs milliseconds (JS=ms, backends=seconds)
  • •Multi-language code examples (6+ languages) + JWT and timezone guidance

Generated with AI, which can make mistakes.

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