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After hundreds of user interviews and 2.5 million recordings — we’re excited to share that Replay.io is shipping today! Download Replay and let us know what you think!

Tl;dr What is Replay?

Replay lets you record your website and replay it down to a line of code. You can see…


Replay is designed for recording and replaying interpreted language runtimes. In previous posts we’ve talked about how Replay’s recorder works and the ways in which recording is specialized to work well on runtimes. This lets us replay what the runtime is doing, but isn’t enough to allow actually inspecting the…


In the last post we discussed the sources of non-determinism which Replay’s recorder captures and controls for in order to replay the original recorded program’s behavior. If these are completely accounted for then the replayed program will behave in exactly the same manner that it did while recording. This isn’t…


Computer programs are largely deterministic. Programming languages and the machine code which they compile down to both have defined semantics, and when repeatedly run against the same initial state a program will do the exact same thing in lock step. …


This series of blog posts explains how Replay works: what happens when a recording is created, how that recording is replayed, and how the replayed program is analyzed to get the information needed to debug it.

First, though, what are we recording? Replay’s devtools are based on a time travel…


Or, How I spent 2 hours arguing with myself over Safari

Over at replay.io, we’re creating a new way to understand your software and fix bugs by recording the execution so you can play it back, debug it, and share it with others. …


Photo by Mohamed Osama on Unsplash

Applications get complex very quickly. Bugs become harder to identify, build times get longer and longer, and issues can only be reproduced with a specific state. Eventually, we run into a situation too complex for print statements and turn to more powerful debugging tools.

Hot reloading, time travel, and step-through…


Old icons on the left, new icons on the right

The short version

At Replay.io, we’re designing a tool that lets you record websites, add annotations to the recording, and debug issues. Our product has three icons as part of our devtools that refer to Comments, Source Explorer, and Pause Information. We recently updated them from the icons on the left to the…


First impressions count for a lot!

As I mentioned in this week’s changelog, my startup is spending a lot of time on “onboarding,” the UX term for welcoming someone to your product. Our onboarding design has to handle a fair bit of complexity. First, we have two products, a browser and a web-based experience. We have…


May 23, 2021

Hello! We’re a young startup called Replay.io. We help software teams fix issues much faster because we’ve invented a time-traveling debugger. If you’re a web developer or work with one, go check it out!

This week we closed 37 issues on our Github, and most of it can be boiled…

Replay

Behind the scenes at Replay.io

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