Sentry is an application monitoring tool that surfaces errors and performance problems. It minimizes the need to manually look at logs or dashboards by identifying common problems across applications and frameworks.
David Cramer is the co-founder and CTO of Sentry.
This episode originally aired on Software Engineering Radio.
Topics covered:

What's Sentry?
Treating performance problems as errors
Why you might no need logs
Identifying common problems in applications and frameworks
Issues with Open Telemetry data
Why front-end applications are difficult to instrument
The evolution of Sentry's architecture
Switching from a permissive license to the Business Source License

Related Links

Sentry
David's Blog
Sentry 9.1 and Upcoming Changes
Re-Licensing Sentry

Transcript
You can help edit this transcript on GitHub.
[00:00:00] Jeremy: Today I'm talking to David Kramer. He's the founder and CTO of Sentry. David, welcome to Software Engineering Radio.
[00:00:08] David: Thanks for having me. Excited for today's conversation.
What's Sentry?
[00:00:11] Jeremy: I think the first thing we could start with is defining what Sentry is. I know some people refer to it as an error tracker. Some people have referred to it as, an application performance monitoring tool. I wonder if you could kind of describe in, in your words what it is.
[00:00:30] David: You know, as somebody who doesn't work in marketing, I just tell it how it is. So Sentry started out doing error monitoring, which. You know, dependent on who you talk to, you might just think of as logging, right? Like that's the honest truth. It is just logging just a different shape or form. these days it's hard to not classify us as just an APM tool that's like the industry that exists.
It's like the tools people understand. So I would just say it's an APM tool, right? We do a bunch of things within that space, and maybe it's not, you know, item for item the same as say a product like New Relic. but a lot of the overlap's there, so it's like errors performance, which is like latency and sort of throughput.
And then we have some stuff that just goes a little bit deeper within that. The, the one thing i would say that is different for us versus a lot of these tools is we actually only do application monitoring. So we don't do any since like systems or infrastructure monitoring. Meaning Sentry is not gonna tell you when you need to replace a hard drive or even that you need new hard, like more disk space or something like that because it's just, it's a domain that we don't think is relevant for sort of our customers and product.
Application Performance Monitoring is about finding crashes and performance problems that users would associate with bugs
[00:01:31] Jeremy: For people who aren't familiar with the term application performance monitoring, what is that compared to just error tracking?
[00:01:41] David: The way I always reason about it, this is what I tell new hires and what I would tell, like my mother, if I had to explain what I do, is like, you load Uber and it crashes. We all know that's bad, right? That's error monitoring. We capture the crash report, we send it to developers. You load Uber and it's a 30 second spinner, like a loading indicator as a customer.
Same outcome for me. I assume the app is broken, right? So we also know that's bad. Um, but that's different than a crash. Okay. Sentry captures that same thing and send it to developers. lastly the third example we use, which is a little bit more. I think, untraditional, but a non-traditional rather, uh, you load the Uber app and it's like a blank screen or there's no button to submit, like log in or something like this.
So it's kind of like a, it's broken, but it maybe isn't erroring and it's not like a slow thing. Right. Same outcome. It's probably a bug of some sorts. Like it's what an end user would describe it as a bug. So for me, APM just translates to there are bugs, user perceived bugs in your application and we're able