Lean vs SPIN

Lean9.1Visit SPIN8.8Visit

Higher score Lean #5 in Formal Verification Tools 9.1/10 Open source ✓ 1 of 2 features Visit Lean

vs

SPIN #7 in Formal Verification Tools 8.8/10 Free plan Free plan✓ 1 of 2 features Visit SPIN

• Lean fits best

  Modern dependent-type verification

• SPIN fits best

  Concurrent-system model checking

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Side by side

Feature	Lean 9.1/10 Visit ↗	SPIN 8.8/10 Visit ↗
At a glance
Editor score	9.1	8.8
Ranking	#5 in Formal Verification Tools	#7 in Formal Verification Tools
Best for	Modern dependent-type verification	Concurrent-system model checking
Pricing model	Free	Free
Starting price	Open source	Free plan
Free plan	Not checked yet	✓ (best)
Free trial	—	—
Deployment	Cloud, Self-hosted	Self-hosted
Platforms	Web, Windows, macOS, Linux	Windows, macOS, Linux
Support	Community, Docs	Docs
Built for	Solo, Small business, Mid-market, Enterprise	Solo, Small business, Mid-market, Enterprise
Features Lean 1/2 · SPIN 1/2
Counterexamples	Not checked yet	✓ (best)
Proof artifacts	✓ (best)	Not checked yet
Specs
Verification method	Deductive	Model-checking
Supported formalisms	Theorem-proving	Temporal-logic
Input languages	Lean 4	Promela
Deployment	Both	Self-hosted
Our review
Pros	Kernel-based checking produces independently checkable proof terms. Tactics and metaprogramming support extensible proof automation. Works across web, desktop, Linux, and self-hosted environments.	Promela models support concurrent-system and protocol analysis Checks deadlocks, assertions, invariants, cycles, and temporal logic Replayable counterexamples and generated C verifiers support diagnosis
Cons	Its formalism focus is theorem-proving rather than a broad multi-formalism toolkit. The listed editor integration is centered on Visual Studio Code. Lean 4 is the listed input language for formalization workflows.	Requires systems to be described in the Promela language Self-hosted deployment places setup and operation on the user Its focus is concurrent-system verification rather than broad software analysis
Our verdict	Lean combines interactive theorem proving with a dependently typed functional programming language. It is intended for formalizing mathematics, verifying software and hardware, and developing reliable programs. The open-source distribution… Read the review →	SPIN is an open-source formal verification tool for concurrent systems and communication protocols. It is designed for researchers, educators, and engineers who need to model system behavior in Promela and analyze it locally. The workflow… Read the review →

Strengths and trade-offs

• Lean — where it wins

  • Kernel-based checking produces independently checkable proof terms.
  • Tactics and metaprogramming support extensible proof automation.
  • Works across web, desktop, Linux, and self-hosted environments.

  Where it doesn't

  • Its formalism focus is theorem-proving rather than a broad multi-formalism toolkit.
  • The listed editor integration is centered on Visual Studio Code.
  • Lean 4 is the listed input language for formalization workflows.

• SPIN — where it wins

  • Promela models support concurrent-system and protocol analysis
  • Checks deadlocks, assertions, invariants, cycles, and temporal logic
  • Replayable counterexamples and generated C verifiers support diagnosis

  Where it doesn't

  • Requires systems to be described in the Promela language
  • Self-hosted deployment places setup and operation on the user
  • Its focus is concurrent-system verification rather than broad software analysis

• Lean9.1/10 · Open source

  A kernel-checked Lean 4 environment for formal mathematics and verified programs.

  Visit LeanFull verdict →
• SPIN8.8/10 · Free plan

  A focused, self-hosted model checker for analyzing concurrent systems and protocols.

  Visit SPINFull verdict →