→ curl -sf https://redline.dev/install.sh | sh
The kind where the logs say nothing useful. Where you've printf-debugged your way across six files and the production page still loads blank for one user in Kansas. You start to doubt yourself. Maybe it's the database. Maybe it's the network. Maybe it's you.
Race conditions don't announce themselves. They wait until you've shipped, until there's a demo, until your phone rings at 2:04am. The stack trace you have is from three call-frames too high. The actual error dissolved into an async callback nobody thought to instrument.
Redline was built for that silence — the one between realizing the bug exists and understanding why it does. We close that gap. Every hidden internal, every skipped frame, every deferred callback that got swallowed before anyone could read it.
What Redline does
Most debuggers stop at the framework boundary. Redline doesn't. Every internal call, every runtime shim, every lazy-loaded module — all surfaces in a single scrollable trace with source-mapped line numbers, not minified garbage. You'll find the real origin of every exception, not the polite place it was caught.
Git-log aware. Feed Redline a failing test and a date,
and it walks your commit history automatically — narrowing the bad
commit down in three steps or fewer. No more git bisect rituals at 3am.
Hot paths in real time — not after the fact, not in a post-mortem analysis you'll never read. Watch your call graph breathe. Spike at 800ms? You'll see it form before the user notices the lag.
Every crash recorded is a crash you can rewind. Exact thread scheduling, exact heap state, exact I/O sequence — replayed on demand, as many times as you need to understand what happened. No more "it only happens in production." Production comes to you.
"I shipped Redline after losing 11 hours
to a race condition I couldn't reproduce."
Get running now
One-line installer, runs on macOS and Linux. No build chain, no dependencies.
Point Redline at the runtime where the crash lives. Watch mode picks up file changes automatically.
Every stack trace is captured, deterministic, and rewindable. Bisect commits or replay the exact thread state from 2am.
Why Redline exists
I
We don't believe in bugs that "can't be reproduced." We believe in tools that weren't recording. Every crash has a sequence. Every sequence can be captured. The only thing standing between you and the answer is instrumentation.
II
We don't believe debugging should require seniority. The 2am crash is a rite of passage only because tooling failed first. A junior engineer with Redline finds the race condition. A senior engineer with a printf loop does not.
III
We don't believe in observability as a retrospective. Your system should be legible while it runs, not only after it falls. Redline is the glass wall between you and your running code — permanent, clear, never fogged.
Free for individual developers. No card required.
Install in 10 seconds →