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Tech riderRev. 30 Sept 2026

Isabelle

Ch 077.1of 33 Formal Verification Tools
  1. 1Runs onLinux, Mac, self-hosted, Windows
  2. 2CostsFree plan
  3. 3Verification methoddeductive
  4. 4Supported formalismstheorem-proving
  5. 5CounterexamplesYes
  6. 6Proof artifactsYes
  7. 7Input languagesIsabelle/Isar, Isabelle/Pure, ML; executable specifications can generate SML, OCaml, Haskell, and Scala
  8. 8Deploymentself-hosted
8 lines stated Written from the maker's own pages: isabelle.in.tum.de
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The Isabelle homepage

Overview

Isabelle is ranked #7 of 33 in formal verification tools on Specifiction. It runs on Linux, macOS, Self-hosted, Windows. There is a free plan.

Isabelle plans and pricing

All plans
Isabelle Free Distributed for free · open-source licenses, with the main code-base subject to BSD-style regulations isabelle.in.tum.de · 30 Sept 2026

Compared on formal verification tools

Free plan
Yesisabelle.in.tum.de
Verification method
deductiveisabelle.in.tum.de
Supported formalisms
theorem-provingisabelle.in.tum.de
Counterexamples
Yesisabelle.in.tum.de
Proof artifacts
Yesisabelle.in.tum.de
Input languages
Isabelle/Isar, Isabelle/Pure, ML; executable specifications can generate SML, OCaml, Haskell, and Scalaisabelle.in.tum.de
Deployment
self-hostedisabelle.in.tum.de

Facts

What it does
Isabelle is a generic proof assistant for expressing mathematical formulas in a formal language and proving them in a logical calculus.isabelle.in.tum.de · 30 Sept 2026
Main uses
Its main applications are formalizing mathematical proofs and formal verification, including proving properties of hardware, software, programming languages, and protocols.isabelle.in.tum.de · 30 Sept 2026
Isabelle/HOL
Isabelle/HOL provides a higher-order logic theorem proving environment intended for large applications.isabelle.in.tum.de · 30 Sept 2026
Proof tools
Proof productivity tools include a classical reasoner, a simplifier, linear arithmetic automation, algebraic decision procedures, and access to external first-order provers through Sledgehammer.isabelle.in.tum.de · 30 Sept 2026
Proof language
Isar is a structured proof language whose proof text is intended to be understandable to both people and computers.isabelle.in.tum.de · 30 Sept 2026
Code generation
Isabelle/HOL can turn executable specifications into code in SML, OCaml, Haskell, and Scala.isabelle.in.tum.de · 30 Sept 2026
IDE
Isabelle/jEdit is the default user interface and Prover IDE, providing continuous proof checking with real-time feedback and semantic markup.isabelle.in.tum.de · 30 Sept 2026
Additional editor
The Isabelle2025-2 release includes Isabelle/VSCode, with GUI panels for Documentation, Symbols, and Sledgehammer.isabelle.in.tum.de · 30 Sept 2026
Platforms
The application bundles support Linux, Windows, and macOS; the site also provides a self-contained Docker image without GUI support.isabelle.in.tum.de · 30 Sept 2026
Libraries and examples
The distribution includes a large theory library of formally verified mathematics, and the Archive of Formal Proofs provides additional applications from mathematics and software engineering.isabelle.in.tum.de · 30 Sept 2026
Security design
The overview says Isabelle follows the LCF system approach so users can write proof procedures and theory extension packages in ML without breaking system soundness.isabelle.in.tum.de · 30 Sept 2026
Windows limitation
The Windows application lacks developer signatures and certificates, so Microsoft rejects it by default when first run.isabelle.in.tum.de · 30 Sept 2026
macOS limitation
The macOS application lacks developer signatures and certificates, so Apple rejects it by default and requires the user to allow it to open.isabelle.in.tum.de · 30 Sept 2026
Support
Support is available through official documentation, the isabelle-users and isabelle-dev mailing lists, Zulip, and Q&A sites listed by the project.isabelle.in.tum.de · 30 Sept 2026

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Where it ranks on Specifiction

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