Why include a timestamp in API request signatures?
A timestamp makes signatures time-bound so replayed requests can be rejected outside a short acceptance window.
EpochConverter API Timestamp for Request Signing (2026)
If you searched for epochconverter api timestamp, you are likely implementing HMAC-signed API requests where stale signatures must fail fast. In 2026, stable signing flows depend on one strict timestamp contract: one unit, one replay window, and one canonical string format before hashing.
The safest pattern is to generate the Unix value right before signing, pass it in a dedicated header, and reject requests outside the allowed clock skew. Always validate the timestamp unit before signature verification to avoid false negatives caused by seconds versus milliseconds drift.
Signing checklist
- Define one timestamp unit in API docs and enforce it at the edge.
- Include timestamp, method, path, and body hash in the canonical signing string.
- Reject requests outside your replay window before hitting business logic.
- Log both raw timestamp and parsed UTC value for incident debugging.
Related EpochConverter pages
For broader API patterns, read epochconverter api timestamp guide. Need a live API-oriented example? Open current epoch time now API. To decode signature logs, use Unix timestamp to date.
Need a quick converter while testing headers? Open the main epoch converter tool.
Related developer tool
If your signed endpoints are polled on a schedule, validate interval expressions with Cron Expression Builder.
Frequently Asked Questions
Should signing use epoch seconds or milliseconds?
Use one format consistently across clients and servers. Seconds are common for compatibility, while milliseconds need stricter validation.
How strict should replay-window validation be in 2026?
Most APIs use 30 to 300 seconds depending on tolerance for clock drift and network latency. Keep the same window across all regions.
What causes the most signature timestamp bugs?
Precision mismatch is the top cause: one side signs 10-digit seconds while the other verifies against 13-digit milliseconds.