Prusti

Free#27 of 35 in Formal Verification Tools

Prusti: A free, open-source verifier for Rust safety properties and code contracts. Ranked #27 of 35 in Formal Verification Tools by our editors (6.8/10); pricing: Free plan; best for rust safety-property verification.

6.8/10★★★☆☆Editor score

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At a glance

• Editor score
  6.8 / 10
• Pricing
  Free plan
• Best for
  Rust safety-property verification
• Free plan
  Yes
• Paid from
  Free
• Verification method
  Deductive
• Facts checked
  20 Sep 2026

• Where it wins

  • Checks panics, integer overflows, and contract properties
  • Generates counterexamples when verification properties fail
  • Supports command-line and Visual Studio Code workflows

• Where it doesn't

  • Targets Rust rather than multiple programming languages
  • Official materials describe it as a prototype verifier
  • Initial versions target a limited Rust fragment without unsafe features

Our verdict on Prusti

Prusti is an automated formal verifier for Rust, built on the Viper verification infrastructure. It is intended for developers who need deductive verification of safety properties and functional behavior, including absence of panics, integer-overflow checks, preconditions, postconditions, assertions, and loop invariants. Rust-like annotations describe contracts and other specifications, while the tool supports command-line use and a Visual Studio Code verification workflow. Prusti is free, open source, and self-hosted across Windows, macOS, and Linux.

Its strongest fit is contract-focused verification within Rust projects. Developers can express assumptions, refutations, external specifications for functions and libraries, and loop-body invariants, then receive counterexamples for failed properties. That combination makes Prusti useful when ordinary testing is not enough to document or check intended behavior. The Visual Studio Code extension adds an editor-based workflow, while the command-line tooling suits projects that prefer repository-based verification steps. There are no AI features, so the product's value is centered on formal specifications and automated checking rather than AI-assisted development.

The main trade-off is scope. Prusti supports Rust as its input language and focuses on a limited fragment in its initial versions; official ETH Zurich materials also describe it as a prototype and note that those versions target Rust without unsafe features. Teams seeking a Rust verifier for code that fits this supported scope should consider Prusti, particularly when open-source, self-hosted tooling matters. Teams needing broader language coverage or verification support beyond the stated Rust fragment should choose a tool aligned with those requirements instead.

Questions about Prusti

What does Prusti run on? Windows, macOS and Linux. It runs self-hosted and as a desktop app.

What does Prusti integrate with? 1 integration: Visual Studio Code.

Who is Prusti built for? Solo users and small businesses (our editorial estimate).

Your product? Our editors can test Prusti in depth and publish a review, labelled as paid · from $149/mo →

Prusti pricing

Prusti fact sheet

Prusti integrations

Prusti lists 1 integrations on its own site.

• Visual Studio Code

Alternatives to Prusti

• IIsabelleA free, open-source proof assistant for broad mathematical and systems verification.9.4
• RocqA free, kernel-checked theorem prover with dependent types, automation, and certified extraction.9.3
• PPVSA broad, self-hosted environment for hybrid formal verification workflows.9.2

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Featured on iTechGuides

Reviewed by iTechGuides Editors · Editorial team · Updated Nov 2026

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Last updated 14 Nov 2026 · How we research and update