Kerno | Local code validation at agent speed

The faster the feedback loop, the better the output.

AI agents write code that looks right in isolation. Kerno makes sure it doesn't break at integration.

Run multiple worktrees with confidence knowing Kerno will flag breaking changes and behavior drifts before they make it to PR.

/Kerno validate

Validate every code change on-demand in flow against real services.

Supports your dependencies

Kerno automatically orchestrates your app and its dependencies locally and mocks external dependencies so your tests run against the same stack your code runs on.

Supported envs →

"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

Supports your dependencies

Learn about diff detection →

Kerno captures the baseline behavior of critical paths for your REST endpoints, then compares your code changes to the baseline and flags diffs.

Kerno will validate:

As your app evolves, Kerno retires stale tests and generates coverage for new behavior automatically. You'll never manually maintain a test suite again.

Learn about test maintenance →

"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

Supports complex codebases

Kerno indexes your codebase to build a deep understanding of how everything works together and test every critical flow of your application.

Supports your backend language

Coming soon

Kerno shifts validation and testing to the point of code generation

"We were using Cursor heavily and had no real safety net. Kerno was running in minutes, and suddenly we could move fast without that low-level anxiety every time an agent touched something critical. It's now a non-negotiable part of our stack."

Jonathan Bernales

CTO

42%

Fewer breaking changes reaching production

3×

Faster feedback. No more waiting on CI

10h

Saved per developer each week fixing issues post-merge

30%

Reduced token consumption using Kerno index tools

How Kerno compares

Validate every code change on-demand in flow against real services.

Focus

Automated backend integration testing

General AI coding assistant that can write tests

Developer interface

Automated

Detects endpoints, database schemas, and dependencies, then generates runnable integration tests automatically

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Environment setup

Built-in

Runs tests automatically in isolated environments with containers, seeded data, and teardown logic

External

No built-in execution layer; relies on user-managed test frameworks

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Feedback timing

Automated

Automatically provisions Postgres, Redis, or other dependencies through Docker Compose

Manual

Developer must configure all dependencies manually

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Test maintenance

Automated

Tracks API, schema, and config changes, then self heals or adds/removes affected tests

Manual

No automatic maintenance; generated tests must be manually updated

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

When it validates

Built-in

Compares baseline and head commits to identify regressions

None

No regression comparison or state tracking

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

MCP / agent native

Built-in

Deterministic guardrails ensure tests always run successfully out of the box

None

Quality depends on prompt phrasing and LLM randomness

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Agent self-correction

Built-in

Deterministic guardrails ensure tests always run successfully out of the box

None

Quality depends on prompt phrasing and LLM randomness

Manual

Can generate test files through LLM completions, but requires explicit back and forth prompting

Kerno gives your AI agent the local CI feedback loop it needs to verify and fix its work in context and ship code that works as part of your system.

AI Code Agent

Requires manual prompting and oversight as code & infra evolve

The agent sets up and maintains the env when prompted. Each dependency, config, or service change requires explicit direction.

Kerno

Sets up and updates your env automatically as code & infra evolve

Your app, its dependencies, and external APIs are automatically provisioned and updated as code and configs change.

Impact

Validation runs against the correct up-to-date environment

Tests always run against an env that matches the current code. No failures from stale or drifted environments across your teams.

AI Code Agent

Blast radius inferred via grep, with predictable blind spots

The agent greps the codebase and misses indirect references, and any code path the agent doesn't think to search for.

Kerno

Deterministic and complete blast radius on every code change

Traces every endpoint, and dependency reachable from the changed code through its deterministic codebase graph.

Impact

Regressions don't slip through agent blind spots

Regressions from unforeseen ripple effects don't slip through the validation process, reducing prod risk and post-merge rework.

AI Code Agent

Validation comes from remote CI, outside the agent's code gen loop

Integration validation runs in CI after push, decoupled from the agent's session, making fixes more complex and expensive.

Kerno

Validation runs locally on every change in-session

Integration validation runs locally as the agent makes changes. Results arrive in seconds, in the same session.

Impact

Better agent output thanks to faster feedback loops

The agent verifies and fixes its work in context and outputs code that won't break your system.

AI Code Agent

Test suite updates require manual prompting by engineers

Adds, removes, and updates require explicit prompting. Engineers have to know what to ask for.

Kerno

Continuously detects and flags when tests need to be updated

Continuously watches code, config, and logic changes and proposes the needed test changes before PR.

Impact

Your test suite stays aligned with your codebase

Stays current as the codebase evolves without extra manual effort for your engineering team.

AI Code Agent

Validation quality varies engineer to engineer

Prompting skils, and local setup shape what gets validated and how thoroughly.

Kerno

Consistent validation quality on every code change

Every change passes the same validation, regardless of the engineer's prompting skills.

Impact

Maintain velocity without sacrificing quality

Agents keep pushing code at speed across the team without raising production risk.

Your code is always secure

Built for enterprise. Ready on day one.

SOC 2 Type II (audit in progress)

Enterprise-grade compliance isn't an afterthought — it's been built in from the start.

Encrypted end to end

Kerno encrypts data in-transit with TLS 1.2 and at-rest using AES 256-bit encryption.

Zero code retention

Your private code is strictly off-limits and is never stored or used for training purposes.

FAQs

Frequently asked questions

Got more questions? Drop us a message on Discord.

Local code validation at CI ‍agent speed.

AI agents generate code faster than your engineers can validate. Breaking changes pile up in PRs, and CI catches them too late causing expensive reworks, delays, and production risk.

AI agents write code that looks right in isolation. Kerno makes sure it doesn't break at integration.

Validate every code change on-demand in flow against real services.

Kerno indexes your codebase to build a deep understanding of how everything works together and test every critical flow of your application.

Kerno shifts validation and testing to the point of code generation

Validate every code change on-demand in flow against real services.

Kerno gives your AI agent the local CI feedback loop it needs to verify and fix its work in context and ship code that works as part of your system.

Built for enterprise. Ready on day one.

SOC 2 Type II (audit in progress)

Encrypted end to end

Zero code retention

Frequently asked questions