# What is an audit trail?

> An audit trail records who changed what and when. Why time and payroll records need one, and what a good audit log contains.

URL: https://timetracking.tech/glossary/audit-trail
Language: en
Last updated: 2026-10-24

**Definition:** An audit trail is a chronological record of every relevant action in a system: who created, changed, approved or exported something, when, and what the old and new values were. A good audit trail cannot be edited afterwards.

## Why hours need an audit trail

Hours are money and, in many countries, also a legal record. When a worker, client or inspector asks why a timesheet shows 7.5 hours instead of 8, you need to show who changed it, when and why. Without a trail, the only answer is whatever the system says now.

An audit trail also protects the people who work with the data. A planner who corrected a shift, or a client who approved hours, can show exactly what they did.

- Who did it (user, client or API key)
- What changed, with old and new values
- When it happened
- Approvals, exports and locks

## The audit log in TimeTracking

TimeTracking writes an append-only audit log: entries are added, never changed or deleted. It covers edits to hours, approvals, exports, period locks and changes to settings, including those made through the API. Office admins can search it in the web app.

- [Period lock](https://timetracking.tech/glossary/period-lock)
- [BAG ruling on time recording](https://timetracking.tech/glossary/bag-ruling-time-recording)
- [Magic link](https://timetracking.tech/glossary/magic-link)