Free estimator

Blast Radius Estimator

See how far a change reaches — and why reach, not diff size, is what predicts risk.

Direct dependents

Callers of the changed symbols

Transitive dependents

Everything downstream of those

Shared contracts touched

Interfaces/APIs others rely on

Services affected
Owning teams
Change type

An estimate from structural reach. Skaftor computes blast radius from your actual dependency and ownership graph. Nothing leaves your browser.

48/100
Moderate blast radius
Add a reviewer who owns a downstream area and run integration tests on affected services.

Learn the metric: Blast Radius.

Frequently asked questions

What is blast radius?

A change's blast radius is the full set of components, contracts, services, and teams it can affect — directly or transitively. Measuring it before merge answers 'what could this break?' so review and testing match real risk.

How is blast radius calculated?

By traversing the dependency and ownership graph from the changed symbols outward: direct callers, transitive dependents, shared contracts, affected services, and owning teams. This estimator approximates that from counts you enter; Skaftor computes it from your actual graph.

Isn't a small diff always low-risk?

No. Lines changed measures size; blast radius measures reach. A one-line change to a widely-used interface can have a large blast radius, while a big diff in an isolated module can have a small one. Reach predicts risk better than size.

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