Sider
The business, the turning points, and the decisions behind them.
01 / WHAT IT BUILT
What the company did
Sider was a Tokyo-based automated code review tool that integrated officially with GitHub. Built on static code analysis and a suite of open-source analyzers, it scanned pull requests for style violations, code quality, security issues, and dependency problems, posting results as comments on the pull request. It supported languages including Ruby, PHP, JavaScript, TypeScript, Java, Python, and Go, and was free for open-source projects.
02 / Sider FAILURE REASONS
Failure reasons
Sider never reached sustainable scale: after the original developer Actcat renamed itself to Sider Inc., the business was transferred in 2019 to Sleeek Corporation, a Fixstars subsidiary, with only about 10,000 users at the time. The Sider service was discontinued in 2022 while the operating company was loss-making - its fiscal 2022 accounts showed a net loss of ¥58.96 million - and the operator completed liquidation on March 4, 2025.
03 / EVENT HISTORY
Events in the structured record
- SideCI launched
Tokyo startup Actcat begins developing SideCI, an automated code review tool integrated with GitHub, in April 2014; a technical-debt kanban feature for Ruby follows in 2016.
- Renamed to Sider
The service and the company are renamed from SideCI to Sider; Actcat becomes SideCI Inc. and then Sider Inc.
- Business transfer
Sider Inc. transfers the Sider business to Sleeek Corporation, a wholly owned subsidiary of Fixstars, on October 31, 2019; Sleeek later renames itself Sider Inc.
- Service discontinued
The Sider code review service is discontinued in 2022; the operator's fiscal 2022 accounts show a net loss of ¥58.96 million.
- Liquidation concluded
The operating company, Sider Inc., completes liquidation on March 4, 2025.
04 / CONTEMPORARY REBUILD ASSESSMENT
Difficulty of rebuilding this project today
Material for this section is being gathered and checked. It will appear here once ready.
Overall assessment: Not completed
05 / CAUSAL CHAIN
How the factors connect
- 01
Sider raised about $7 million in venture funding during its lifetime.
- 02
The operating company's fiscal 2022 accounts (year ended September 30, 2022) reported a net loss of ¥58,956,000 (about $449,000) on total assets of ¥88.83 million.
- 03
The Sider service was discontinued in 2022 and the operator completed liquidation in March 2025.