IELE

IELE is a virtual machine and intermediate language developed by IOHK for Cardano. It was introduced to provide a safe, portable, and verifiable execution environment for smart contracts and blockchain applications, with support for multiple front-end languages.

Architecture and semantics: IELE uses a register-based instruction set and a formal operational semantics, designed to be amenable to formal verification and reasoning about correctness. It aims to serve as an intermediate representation that can compile from high-level languages and target multiple backends.

Compiler and languages: The IELE toolchain provides compilers that translate languages such as Java-like or other languages to IELE bytecode, enabling cross-language development. It emphasizes deterministic execution and sandboxing to prevent contract bugs.

Role in Cardano: During the early development of Cardano's Goguen era, IELE was proposed as part of Cardano's multi-language contract strategy, alongside languages like Plutus and Marlowe; IELE's goals included cross-language interoperability and formal verification.

Status and reception: While IELE contributed to the research discourse around safe smart contract execution, Cardano's mainnet smart contracts have since been deployed primarily using Plutus (Haskell-based) and Marlowe; IELE remains an experimental or historical element in the Cardano ecosystem.