Informal Systems

• Name: Informal Systems
• URL: https://informal.systems/
• Category: formal-verification and protocol-assurance tooling stack / behavioral-audit infrastructure / reusable distributed-systems verification surface
• Summary: Informal Systems at the project layer is the reusable assurance surface inside a broader company-run methodology shell. The useful cut here is the public report corpus plus the modeling, verification, and test-generation stack — Quint, Apalache, Modelator, cosmwasm-to-quint, and CI-oriented verification harnesses — that protocol teams can adopt directly. The broader entity boundary now lives in informal-systems, which is the cleaner place to reason about who packages the audit method, curates the report corpus, and steers the verification workflow clients inherit.
• What it does:
  • Publishes a large public audit-report corpus spanning IBC-adjacent systems, dYdX, Celestia, Neutron, Namada, Osmosis, Zenrock, Ripple, and other distributed-system clients
  • Develops and maintains verification and testing tools including Quint, Apalache, Modelator, and cosmwasm-to-quint
  • Exposes a behavioral-audit posture that emphasizes modeling intended behavior, verifying properties across possible states, and comparing those properties against implementation and production execution
  • Delivers verification harnesses intended to plug into CI so assurance can continue after the initial audit engagement
  • Packages reusable model-based techniques that move the note beyond audit firm into a durable engineering surface teams may actually build around
• Key claims:
  • The public audits repository says Informal applies a multi-layered, automated approach to security audits for the blockchain ecosystem under researchers in protocol design, verification, and testing
  • The same repository says Informal uses tools such as Quint, Apalache, and Atomkraft to make distributed systems secure and resilient
  • Informal’s audit-services material says the firm audits system behavior, not just code, by modeling intended behavior, verifying properties across possible states, and comparing those properties against implementation and real-world execution
  • The same audit-services material says customers get a verification harness that can plug into CI so every code change is checked against critical security properties, which strongly suggests a continuous-assurance posture rather than a point-in-time report business
  • The Model Based Techniques page says Informal uses model-based techniques in both its own development practice and its security audit services
  • That page also lists Quint, Apalache, Modelator, and cosmwasm-to-quint as first-party tools that make model-based techniques easier to incorporate into development and auditing
  • The audits repository shows public reports across several years and ecosystems, reinforcing that Informal operates a reusable assurance surface rather than only a narrow one-off services business
• Whitepaper: No canonical standalone Informal Systems whitepaper or litepaper surfaced in this pass. The clearest current sources of truth were the public audits repository, the audit-services materials, and the Model Based Techniques documentation; see ../whitepapers/informal-systems-primary-sources-2026-05-04.md.
• Sources:
  • https://informal.systems/
  • https://quint.sh/audits
  • https://mbt.informal.systems/
  • https://raw.githubusercontent.com/informalsystems/audits/main/README.md

Internal linkages

• Company boundary for the broader methodology and workflow shell: informal-systems.
• Strong adjacent project reads when the question is reusable verification tooling rather than the operating organization: certora and openzeppelin.
• Best company-level comparison when the question shifts to who shapes the ecosystem’s default security workflow: trail-of-bits.

Protocol / company boundary

• Keep this note on the reusable assurance surface: the public audit corpus, Quint, Apalache, Modelator, cosmwasm-to-quint, CI-oriented verification harnesses, and the behavioral-audit techniques teams can adopt directly.
• Use informal-systems for the named-operator layer around engagement packaging, audit-method branding, report-curation policy, and the broader company-run workflow that steers how clients inherit those tools and methods.
• That split matters because which verification tools and report artifacts are reusable here? and which company is shaping the assurance method clients operationalize? are related but not identical questions.

Control surface

• At the project layer, leverage sits in the report corpus teams keep re-reading, the modeling languages and checkers they adopt, the verification harnesses they wire into CI, and the behavioral-audit framing that changes what gets reviewed at all.

• For the wider operator boundary around methodology packaging, public-report stewardship, and company-level audit posture, read informal-systems.

• Treat this note as the reusable assurance stack, not the full entity story.

• Last reviewed: 2026-08-13 UTC