A reported sustainability number can change several times before it appears in a report.
Data may be uploaded, corrected, rejected, or reverted. Emission factors may be matched or overridden. A calculation may be finalized and later reopened.
The audit trail records these actions so you can see how a reported number was created and changed over time.
This is useful when reviewing a report or answering questions from an assurance provider. Instead of searching through emails, spreadsheets, and file versions, you can use the audit trail to find the relevant changes.
What the audit trail records
The Trail tab on the Audit page records actions taken across Hydrus.
These include:
- Data: uploads, processing, confirmations, corrections, rejections, reverts, and duplicate removal
- Calculations: creation, factor overrides, manual lines, recalculation, finalizing, reopening, and guided review
- Reports: generation and export
- Facilities: creation, updates, and deletion
- AI activity: actions taken by Hydrus AI on behalf of users
Each event shows:
- Who or what performed the action
- Their role at the time
- What action was taken
- Which record was affected
- When the action happened
When relevant, the event also shows the record before and after the change. Changed fields are highlighted, and the reason for the change is shown when available.
The role shown is the role the person had when they performed the action. If their permissions change later, the original audit record does not change.
Filter the trail to find what you need
The audit trail can contain many events. Use the filters to find the events related to a specific question.
The quick filters include:
- Data changes — Shows events that changed something and hides read-only activity.
- People only — Shows actions performed by users.
- AI only — Shows actions performed by Hydrus AI.
- Overrides & approvals — Shows decisions such as emission factor overrides.
- Last 24h — Shows recent activity.
Use the advanced filters button to narrow the results by:
- Date range
- Entity type, such as data source, report, facility, or calculation
- Actor
- Action
Related events are grouped into an audit chain. This lets you follow a change and the actions that happened after it.
You can also ask the audit log a question in plain language, such as "every factor override this quarter." Hydrus searches recent audit events and returns the relevant results.
Before a reporting close, use the overrides & approvals filter for the reporting period. Check that each override has a clear reason and was made by someone with the correct role.
Replay a number at a specific point in time
The audit trail shows what happened. A replay shows how those changes affected a specific number.
A replay is available for:
- Calculations
- Reports
- Data sources
- Facilities
- Documents
- Emission factors
- Individual records
You can open a replay from a report with the replay timeline button, or from the related calculation.
The replay view has a timeline. Move the slider, or use the step back and step forward buttons, to see the state of the record at a specific point in time.
For a calculation, Hydrus rebuilds the earlier total based on the changes that happened up to that point.
For example, a reviewer may ask:
"What was the Scope 2 total when the draft report was shared in March, and what changed after that?"
In the replay view, move to the relevant date to see the value at that time. You can then step through the changes and see who made each change and why.
Each event in the replay links back to the full audit trail entry and the record that was changed.
Export the audit record
Reviewers may need a copy of the audit record outside Hydrus.
On the Trail tab, the export audit log button downloads the events that match the current filters as:
- CSV
- JSON
The export includes:
- Timestamp
- Actor and role
- Action
- Affected entity
- Details
- Request identifiers
Apply your filters before exporting so the file contains the events relevant to the review. For example, select the reporting period and the overrides & approvals filter before exporting.
In the replay view, the export workpaper button creates a PDF workpaper showing the figure's history. You can also export the history as JSON.
The JSON export also includes a special code that changes if the file is edited. This lets the person receiving the file check that it has not been changed since it was exported.
Opening a replay is also recorded in the audit trail, so there is a record of who reviewed the figure's history.
Who can access the audit trail?
Access to the Audit page is limited to Admin, Editor, and Auditor roles.
The Auditor role allows an internal or external reviewer to read the audit record without changing data, calculations, or reports.
You can give an assurance provider Auditor access instead of sending audit exports back and forth. This allows them to review the audit record and follow their own questions while keeping a record of what they reviewed.
What should the audit trail show?
For a reported number, you should be able to answer:
- What was the number at a specific point in time?
- What data changed?
- What emission factors changed?
- What changed in the calculation?
- Who made each change?
- What role did they have when they made the change?
- Why was the change made?
The audit trail brings this information together in one place. A replay lets you view the state of a number at a specific point in time.
Together, they give reviewers a clear way to follow how a reported number was created and changed.