Type Theorist & Formal Verification Engineer

Role Overview

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Smart contracts are not secure enough for finance, law, or systems engineering.

Smart contracts are security-critical, performance-sensitive, and bug-prone. Heliax is working on a dependently-typed smart contract language, Juvix, which utilises recent advancements in type theory to allow developers to write code in a high-level functional language, compile it to gas-efficient output VM instructions, and formally verify the safety of their contracts prior to deployment & execution. PLT at Heliax focuses on applying the latest research in type theory and programming language design to concrete problems in the distributed ledger space. We are looking for a type theorist and formal verification engineer to work on various parts of the Juvix stack, all the way from formalisation of an operational semantics for the language in Agda to writing formally verified smart contracts in the Juvix language itself. This role offers the chance to work closely with a small team on compelling cross-disciplinary problems in computer science, PLT, cryptography, and economics, and enjoy a high degree of independence in working conditions and prioritisation.


  • Produce formal specifications and implementation plans for new language features in collaboration with team members (and optionally submit to academic venues)
  • Evaluate correctness, suitability, and ease-of-implementation of published type theory and PLT research for the Juvix architecture & project aims
  • Implement both in-house and published research in Haskell in the Juvix codebase in collaboration with team members
  • Conduct code reviews and help maintain a high standard of correctness and quality
  • Write production-ready formally verified smart contracts in the Juvix language itself for various purposes
  • Comprehensively document both design and implementation choices in the codebase, and assist in writing user-facing documentation for the Juvix language

Example subprojects & features


  • Prior experience in functional programming in Haskell, Idris, Agda, or Coq
  • Prior experience in formal verification or formalisation of a language
  • Self-motivated & self-organised
  • Interested in open-source technology and research applied to DLT

Bonus Qualifications

  • Prior academic work in type theory, PLT, or compiler design
  • Prior academic work in cryptography, economics, or game theory


Remote or local (Zürich/Zug, Berlin). When remote, preferred if mostly located within (+/- 7 hours) Central European time zones. Ideally someone who enjoys nature and hiking 🏔️.