Undo is a software debugging company based in Cambridge, UK. Originally known for its time travel debugging technology, the Undo software makes it possible for software engineering teams and AI coding assistants to perform software issue root cause analysis by recording the execution of applications, enabling deterministic replay and inspection of program behavior.
History Undo was initially bootstrapped in 2005 by Greg Law and Julian Smith out of Law's garden shed in Cambridge. Law and Smith developed the core technology that would eventually become UDB (formerly UndoDB), a reversible debugger for Linux software.
LiveRecorder was then developed based on UndoDB to enable development teams to record and replay the execution of software programs.
In 2012, Undo secured its initial seed funding. It closed a $3.3 million Series A funding round in 2016, and a $14 million Series B in 2018.
In 2026, Undo announced they had raised $37 million in new funding, led by Elsewhere Partners.
Products
UDB (formerly UndoDB): Interactive time travel debugging tool for individual developers (supports C/C ++ and SystemC) Undo: Program execution recording and runtime analysis for software debugging and root cause analysis (supports C/C++, SystemC, Rust, Go, Java and Kotlin)
Agentic debugging In 2026, Undo integrated its time travel debugging technology with AI coding agents, Claude Code, OpenAI Codex, and GitHub Copilot. The integrations enable AI agents to inspect recorded executions when analyzing software failures.
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