The response matched. The event was missing.

A migrated reservation service returned the expected response and updated the stock. Bosun still found that the reservation event had disappeared.

Tell us about your challenge See the full approach
Result summary from the public COBOL-to-Rust experiment
Response
Matched
Stock
Matched
Reservation event
Missing
Difference foundReady for engineering review
Read the experiment View the source

Run the same action. Compare what changes.

Parity is the proof language and comparison engine behind this part of Bosun.

  1. Run

    Give the old and new systems the same effective input.

  2. Observe

    Capture the selected result and supported effects.

  3. Compare

    Return the evidence and any differences for review.

Parity compares the actions run and the results and effects selected for observation.

Evidence with a clear scope.

Tests, replay, and engineering review remain part of the migration. Parity gives your team evidence from the selected actions and effects.

The public experiment found a missing reservation event and a changed database operation. Full system equivalence remains outside this experiment.

Start with the system you have.

Tell us what needs to change, what must stay stable, and how your team reviews work today.

Tell us about your challenge Explore the approach