CodeTracer
Dev tools
debugger
SHOW HN2025
334points
52comments
#148of 3,837 in 2025
Top 4%of 2025 by points
How HN took it
MixedNo clear lean
7 positive, 9 neutral or asking, 1 mixed, 4 critical, out of 21 comments about the project. Thread score +0.09.
Idea: 5 for, 1 againstPerformance: 0 for, 1 againstDesign: 0 for, 1 againstExecution: 0 for, 1 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Useful time-travel debugging idea and interface
From 3 comments
The planned RR recordings integration is what I'm most excited about though. Having this capability for systems languages like Rust and C++ would be transformative for complex…
cxie on HNThis happens all the time and is super irksome. Being able to step backwards as well as forwards is super cool. Also, being able to do that with a loop using a slider is cool.
Apofis on HNCongrats on the release! Looks like you have done a great job so far. Doesn't fit a need for me at the moment, but I will keep an eye out for the alternative back-end evolution…
kingforaday on HN
Support for Nim and other under-supported systems languages
From 2 comments
Thank you for building up the nim ecosystem.
esafak on HNYou can appreciate it for building up good, under-supported languages like nim, zig, and D.
esafak on HN
Objections
Headline suggests multi-language support but only Noir works initially
From 1 comment
Windows support? What languages? How does it work? I don’t like that the headline is “designed to support multiple languages” but it only actually supports an obscure language…
forrestthewoods on HN
Closed-source RR backend for system languages
From 2 comments
the support for system languages (the rr integration "backend") is currently closed source. It's not ready yet, and it might be proprietary: it would be great if we can open…
alehander42 on HNWe're working on Windows support for the scripting and blockchain languages. I am sorry if the headline felt misleading or the current support disappointing: we do have…
alehander42 on HN
rr-based backend will not run on macOS
From 1 comment
Very excited for this! I donated on open collective already. The team is full of talented people. A nice interface to time travel debugging, with Nim support soon nonetheless.…
elcritch on HN
Requests
Support for JavaScript/TypeScript
From 3 comments
The Noir support makes sense given its use in ZK proofs where execution tracing is particularly valuable, but I'm really looking forward to the Python and Ruby implementations.…
cxie on HNI love it, I always wished for something like that. Will try to later test with python. Wish there was also for JS/TS. As for rr debugger did it got by now any support for MacOS…
pzo on HNWould love this for JavaScript if that was even possible.
jv22222 on HN
Support for Android, Windows and macOS
From 3 comments
I love it, I always wished for something like that. Will try to later test with python. Wish there was also for JS/TS. As for rr debugger did it got by now any support for MacOS…
pzo on HNIs there anything out there for Android?
optymizer on HNVery excited for this! I donated on open collective already. The team is full of talented people. A nice interface to time travel debugging, with Nim support soon nonetheless.…
elcritch on HN
VSCode extension
From 1 comment
I need a VSCode extension for this. But alas, it's just sitting in their roadmap... Typical. Guess I'll have to roll up my sleeves and build one myself. Not like I have enough on…
cxie on HN
Support for Java/Kotlin on JVM
From 1 comment
Any chance of something like this being available for Java/Kotlin on JVM?
Apofis on HN
Questions
How does the recording work and what are its boundaries
From 2 comments
Congrats on your release! One question I have is, how exactly does it record and what are the boundaries of the recording? For example does it only record the userland execution…
dinnertime on HNHow does it record?
nextn on HN
Performance overhead of tracing on long-running programs
From 1 comment
The Noir support makes sense given its use in ZK proofs where execution tracing is particularly valuable, but I'm really looking forward to the Python and Ruby implementations.…
cxie on HN
Trace file growth in production systems
From 1 comment
Looks really cool, but in production systems, won't the trace files proliferate at extreme speed? How would you correlate the files to a certain session for user identification…
rubenvanwyk on HN
Alternatives named
Replay.io
From 2 comments
> Wish there was also for JS/TS. There’s Replay for browsers and Wallaby for Node.
vlovich123 on HNFor frontend there is https://www.replay.io/ I loved debugging with that when I was working on react web app. Wish there was something like this for react native :(
profstasiak on HN
Undo (UDB)
From 1 comment
https://undo.io/ supports Java
bramhaag on HN
FlowStorm
From 1 comment
If you are using Clojure or ClojureScript check out FlowStorm: https://www.flow-storm.org/
slifin on HN
Ariana
From 1 comment
I just released a JS/TS/Python time travel debugger that overlays variable values on top of vscode. It's just a npm or pip install and VsCode extension so it might be easier to…
anougaret on HN