Sentry (application monitoring)

Sentry began in 2008 as an unlicensed, 71-line Django plugin originally called django-db-log, which logged exceptions from Django projects to a database and exposed aggregate views instead of sending an email for every error.⁠[1][2]

In 2008 David Cramer returned to San Francisco and joined Disqus, a comment-hosting service. He recalled that someone in a Django community channel asked how to log errors to a database, and he wrote an example and pushed it to Google Code. The tool was developed by Disqus Director of Design Chris Jennings and Lead Engineer Cramer while they worked there; it started as an internal tool for exception logging in Django applications and was then open-sourced.⁠[3][4]

Sentry later dropped its Django requirement and became a general Python error-monitoring tool; as core contributors moved to companies that did not use Python, the project added Ruby support (via Chef) and JavaScript support (via Mozilla).⁠[2]

At the suggestion of a product manager at Heroku, Cramer used a Christmas break to build a cloud service for Sentry with Stripe billing; it had a paying customer on the first day and ten within a few days, at a price of seven dollars. The hosted service launched in 2012 with tiered pricing based on the number of exceptions an application throws. Cramer said that for about three years the revenue paid for servers and conference sponsorships, with no income going to the founders.⁠[3][4]

In early 2013 Cramer left Disqus and within months joined Dropbox as an engineer, continuing to run Sentry on the side. By early 2015 Sentry had thousands of paying customers, $600,000 in annual revenue and was profitable. Cramer said more money was needed to hire and compete, and he left Dropbox to raise funding for Sentry.⁠[3]

Cramer’s early cold outreach to investors went unanswered; after former Dropbox colleague Dan Levine reached out, Sentry raised a $1.5 million seed round within months, with the money coming from AccelAccelAccel is a venture capital firm co-founded in 1983 by Arthur Patterson and Jim Swartz. It invests through regional teams and early-stage, growth and late-stage funds, with operations in the United States, Europe, Israel and India. Its investment history includes Facebook, Flipkart, Atlassian, Slack and other technology businesses. Fundraising totals, regulatory assets under management and portfolio-company transaction values are distinct measures.Open the full entry. The team then grew from three to fourteen people within a year, with hires from Dropbox, GitHub and Disqus.⁠[3][4]

In June 2016 Sentry raised a $9 million Series A led by NEA with participation from Accel, to grow the business and hire. Cramer said the round valued the company at more than $40 million post-money and that “the sheer amount of competition forced us down the VC route.”⁠[4]

At the time Sentry’s SaaS product had more than 5,000 customers, about one third of all users including the open-source version, and the company was cash-flow positive; users included Square, Stripe, Dropbox, Uber and Airbnb, and JavaScript had become its top platform.⁠[4]

In May 2017 Sentry had 30 full-time employees in San Francisco, Austin and Vienna; companies such as Stripe and Uber ran Sentry behind their own firewalls, while Dropbox and HubSpot used its cloud service.⁠[2]

In May 2018 Cramer, then CEO, announced a $16 million Series B from NEA and Accel and released Sentry 9, which added ownership-based assignment and a feature called Suspect Commits, with plans to expand into what the company called “APM for Developers.” The company then had nearly 70 employees and was hiring in San Francisco and Vienna.⁠[5]

In January 2020 Cramer announced that former VMware executive Milin Desai would become Sentry’s CEO while he moved to the CTO role to keep driving product and technology. He wrote that the year marked the eighth since Sentry was incorporated; Sentry then had more than 50,000 customers and offices in San Francisco, Toronto and Vienna.⁠[6]

Looking back on the decision, Cramer said: “I gave up board control. I hired a CEO to take my job.”⁠[3]

In February 2021 Desai announced that Sentry had raised $60 million to scale product innovation, its global teams and developer communities; Sentry had added performance monitoring to its application monitoring suite in July 2020. The Series D valued the company at $1 billion.⁠[7][8]

On May 4, 2022 Sentry closed a $90 million Series E co-led by BOND and Accel, with existing investor NEA and new investor K5 Global participating. The round valued the company at more than $3 billion, tripling its valuation in less than 15 months. The company planned to use the money for product development, hiring and expansion in Europe.⁠[8]

On November 30, 2022 Cramer announced that code coverage tool Codecov was joining Sentry. Codecov began in 2014 as a code coverage reporting tool, supported more than two dozen test frameworks and had helped over a million developers; Sentry said both products would continue as usual in the near term and be brought together over time, with Codecov focused on tests and CI infrastructure and Sentry on code once it reaches production.⁠[9]

On April 12, 2023 Sentry announced that Syntax, the web development podcast hosted by Scott and Wes, was joining Sentry. Sentry said Syntax would keep its own brand, launch a new website and make Scott’s Level Up Tutorials free, and that the podcast would no longer run paid advertising. The day coincided with the 600th episode of Syntax.⁠[10]

Sentry was published under BSD-3 from 2009 and switched to the Business Source License (BSL) ten years later; when Codecov, acquired in 2022, had its source published under the BSL, Sentry’s description of it as “Open Source” drew debate. On November 17, 2023 Sentry relicensed Sentry and Codecov under the Functional Source License (FSL), which it wrote itself; the company describes FSL as an evolution of the BSL that bars using the software to compete commercially with Sentry and converts to an open-source license after a set period.⁠[1]

On August 6, 2024 Sentry launched “Fair Source,” which it defines as an approach to software sharing that allows use, modification and redistribution while protecting the producer’s business model; Codecov, CodeCrafters, GitButler, Keygen and PowerSync, previously closed-source products, had been shared publicly under it. Sentry said at the time that more than 10,000 organizations ran Sentry internally under Fair Source licensing, and that it had passed 100,000 cloud customers and $100 million in annual revenue.⁠[11]

On May 6, 2025 Cramer announced that mobile tooling company Emerge Tools was joining Sentry to strengthen its offering for mobile teams, such as helping them ship smaller apps.⁠[12]

On June 17, 2025 Sentry made its AI debugging agent Seer generally available. Seer draws on the stack traces, traces, commit history, logs and profiling data that Sentry collects, along with the codebase, to find root causes, propose fixes and open pull requests automatically.⁠[13]

On February 11, 2026 Sentry announced that it had acquired XcodeBuildMCP, an open-source MCP server that lets AI agents build, test and debug native iOS and macOS apps and that had more than 4,000 GitHub stars; its creator and maintainer Cameron Cooke joined Sentry.⁠[14]

On October 13, 2026 CursorCursorCursor is the trading name of U.S. AI coding software company Anysphere, Inc. and its namesake coding tool. Founded by Michael Truell, Sualeh Asif, Arvid Lunnemark and Aman Sanger, it began as an AI-native development environment forked from VS Code and later shifted toward agent-centered coding. Its November 2025 Series D valued the company at $29.3 billion post-money; on August 14, 2026, SpaceX completed an all-stock acquisition at an implied equity value of $60 billion, making Cursor a wholly owned subsidiary.Open the full entry announced that its Origin platform integrated with more than 20 apps for deployments, CI, code review, security, monitoring and project management, naming Sentry among its partners.⁠[15]

As of November 2026 Sentry’s website lists products including error monitoring, logs, Seer, session replay, metrics, tracing, profiling, uptime monitoring and cron monitoring. The company says it supports more than 100 programming languages, is used by millions of developers and 200,000 organizations in 146 countries, and processes more than 190 billion events a day; its offices include San Francisco, Vienna and Toronto.⁠[16]

As of November 2025 Cramer served as Sentry’s co-founder and chief product officer.⁠[3]

Sentry: Official website: https://sentry.io/ (opens in a new window).⁠[16]

X: Public account: https://x.com/sentry (opens in a new window).⁠[16]

LinkedInLinkedInLinkedIn is a social networking platform for professionals. It was founded in 2002 by Reid Hoffman and others, launched in 2003, and listed on the New York Stock Exchange in 2011; after Microsoft acquired it for approximately $26.2 billion in 2016, it became a wholly owned Microsoft subsidiary. Its revenue comes from membership subscriptions, advertising, and recruitment solutions.Open the full entry: Public profile: https://www.linkedin.com/company/getsentry/ (opens in a new window).⁠[16]