Kerno: Catch breaking backend changes and unintended side effects before raising a PR
AI tools generate backend code fast, but you still need to verify it actually works.
Kerno is a validation engine that helps you catch breaking changes in your AI backend code before raising your PR. It automatically generates, runs, and maintains high-quality integration with full codebase context.
When you make changes, Kerno validates them against your real service and dependencies to catch breaking changes and unintended side effects. All directly in your IDE with instant feedback.
How It Works
1. Codebase indexing
Kerno indexes your codebase to build a deep understanding of how everything works together. Kerno support TypeScript, JavaScript, Python (Go, PHP, Ruby, Java coming soon)
2. Zero-config environment orchestration
Kerno automatically orchestrates your application and its dependencies (PostgreSQL, Redis, MongoDB, Kafka, RabbitMQ, and more) locally with zero manual configuration.
"Kerno was up and running in minutes with no manual work, and it made our API migration so much smoother. We could instantly validate that every change made by Cursor worked the way we expected, and now it's a core part of how we build."
— Misch Strotz, Co-Founder & CEO, Letz AI
3. Baseline Capture & Diff Detection
Kerno captures the baseline behavior of critical paths for your REST endpoints, then compares your code changes to the baseline and flags any diffs.
What Kerno validates:
- Functional API workflows
- Contract & schema validation
- Error handling & resilience
- Authorization & authentication
- Boundary & edge cases
"Kerno saves us a lot of manual work and helps us catch side effects and issues that would definitely break our projects' backends. Our engineering team loves it."
— Santiago J. Valls, Co-Founder & CTO, BeWise
4. Self-Healing Maintenance
As your app evolves, Kerno updates your tests to keep everything in sync without manual effort. Tests are added as features appear and retired as code changes—keeping your suite complete and consistent.
Why Teams Choose Kerno
- 35% fewer breaking backend changes and unintended side effects
- 3X faster feedback loops for developers, leading to fewer PR bottlenecks
- 10+ hours saved each week per developer troubleshooting integration issues post-CI
"Using Kerno with Claude Code has been a game changer. You get quick feedback with no manual effort, and it saves you a lot of time and hassle debugging integration issues post-merge."
— Jonathan Bernales, CTO, Germen
Security & Privacy
- Your code never leaves your machine – The codebase index is stored locally
- Zero-day retention policy – Any processed data is immediately deleted
- Never used for training – Your private code is strictly off-limits
- Enterprise security – SOC 2 Type II compliance in progress
- Encryption – TLS 1.2 in-transit, AES 256-bit at-rest
Requirements
- Docker: Kerno uses Docker to create isolated environments for test execution. Please ensure Docker Desktop is installed and running on your local machine.
- Git: Kerno only supports Git repositories. Make sure your project is initialized with Git.
Learn More
Questions? Drop us a message on Slack community
