• Mesmo is a compiled native library that exports Cardano Client Lib functionalities to Python, Go, Rust and JavaScript without requiring the JVM.
  • Mesmo acts as a complement to existing SDKs, covering the 5% of functions that each main library typically does not yet include.
  • Each supported transaction type is built and submitted in CI against a real Cardano devnet node in all four languages simultaneously.

Mesmo, a compiled native library built on top of Cardano Client Lib (CCL), aims to resolve a structural limitation in the Cardano development ecosystem: the fragmentation of functionalities across SDKs written in different languages.

Mesmo takes CCL —the mature Java SDK maintained by the Cardano Foundation— and compiles it via GraalVM Native Image into a shared library with a standard C ABI, eliminating the runtime dependency on the JVM. On top of that foundation, four idiomatic wrappers for Python, Go, Rust and JavaScript are built.

The Problem of the Missing 5% in Cardano

The Cardano ecosystem has well-established per-language solutions: pycardano for Python, MeshJS and Lucid Evolution for TypeScript, pallas for Rust and Apollo for Go.

These libraries, most of them maintained by small teams or individuals, cover the majority of development needs. However, each hard fork introduces new functionalities —such as the Conway era governance operations, including DRep registration, voting actions and treasury donations— that must be reimplemented separately in each SDK, with all the time that entails.

The result is a recurring gap: the chosen library covers 95% of the requirements, but the remaining 5% is exactly what a product roadmap needs at that moment.

Mesmo Is a Complement, Not a Replacement

Mesmo‘s design is deliberately modular. Its core is stateless —no persistent connections, no chain synchronization— which allows it to integrate alongside any existing SDK without requiring an architectural migration. The chain data needed to build transactions, such as UTXOs and protocol parameters, is incorporated through a ChainDataProvider interface with included implementations for Yaci-Store and Blockfrost.

Plutus script costing follows the same pattern: by default, the Scalus UPLC evaluator embedded in the native core calculates execution units without external services, though the interface accepts custom implementations.

Transactions are described using the declarative TxPlan model, which internally manages input selection, fee calculation and change. The table of supported types covers ADA and native token payments, staking operations, full Conway governance, pools, native scripts and Plutus contracts.

Each of these types is verified in the continuous integration pipeline through real submissions to a Cardano devnet node, in all four languages, on every repository change. Node acceptance is the proof, not a simulation of it.