Built for Linux C/C++ Developers

Root cause your hardest bugs in hours, not weeks

Low-overhead time travel debugging for millions of lines of code

100% compatible with GDB so no need to learn a new tool – just a handful of new commands. Also available as a Visual Studio Code extension.

Resolve customer issues within hours by quickly getting a reproducer

Save time on diagnosing concurrency bugs caused by multithreading

Troubleshoot frustrating flaky tests producing inconsistent results

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Get started in under 2 minutes.
No extra steps required. Debug instantly.

What is Time Travel Debugging?

Record a process. Replay the recording. Resolve the issue.

Reconstruct and examine the full state of the program at any point in time.

Step back in the execution history to inspect the code flow to see what happened.

Record the bug (on-demand or in automated test), capturing the full program execution in a single binary file. No code or build changes are required thanks to Undo’s just-in-time binary instrumentation.
Any question you have can be answered from a recording. No more “how did that happen?”. Recordings are portable, so they can be replayed outside of the original environment and shared with your team.
Examine the full state of the program at any point. Go back and forward in time with ease. Trace from symptom to root cause in one cycle – without having to repeatedly restart your debug session or recompile.
Get started

Get started in under 2 minutes.
No extra steps required. Debug instantly.


Submit a recording of a bug we can’t solve with Undo and WIN a fully paid conference visit of your choice – up to $3,000!

  • Step 1: Capture your bug in a recording using Undo. If you don’t have it, use the free trial.
  • Step 2: Upload your recording below.

Need help to create a recording? No problem. Just book a quick call with one of engineers who can show you how to do it.

Upload recordingBook call with engineer

  • Diagnose memory corruptions, race conditions, and other complex intermittent bugs within days, not weeks or months
  • Quickly rewind to the point of failure in the debugger to understand the root cause
  • Run, step the program backward or forward, or jump immediately to any point in the execution history to see what happened – without having to restart the process again

Get started

No extra set up steps required.
Get started in 2 minutes.

Watch the Demo

Unfamiliar with the codebase? No problem! You don’t have to have it all in your head. Even for experienced developers, bugs in multi-million line codebases always involve something unfamiliar.

A recording captures the whole execution history – every line of code in every thread, every variable, every I/O. Rewind and fast-forward time to see how state changes and why the code behaves the way it does.

  • Get a picture of code flow by exploring how the code is executed dynamically
  • See exactly what happened and how it happened
  • Understand subtle interactions amongst complex components, custom data structures, and confusing locking schemes


Integrates with all popular CI / test automation tools and IDEs

Flexible APIs and CLI tooling make it easy to integrate with custom test environments too

Available for Linux Applications


Step into a Time Machine With Undo

Get started in under 2 mins

See what your software really did
Solve hard bugs - fast
Understand unfamiliar codebases
Get started

Get started in 2 minutes.
No extra set up required.

The Ultimate Guide to Time Travel Debugging

  • What is time travel debugging?
  • How does it differ with standard debugging methods?
  • How does it work under the hood?
  • What type of bugs can it help me RCA?
  • How will it help my team in practice?