Practical overview
When it fits
Use Smplx when developing SimplicityHL contracts and you want a CLI workflow covering project setup, dependencies, builds, testing, and local Liquid integration testing.
Who it is for
- Developers building SimplicityHL smart contracts for Liquid.
- Rust developers who want project, dependency, build, and test tooling for Simplicity contracts.
Documented uses
- Initialize and manage a Simplicity-based project.
- Install SimplicityHL dependencies.
- Build contract files into generated artifacts.
- Run contract tests and fuzz tests.
- Set up local Elements and Electrs nodes for integration testing.
Requirements & limits
The framework is distributed as an open-source Rust project under the MIT license.
- A
simplex.tomlfile is required in the project root. - The configuration supports Liquid, LiquidTestnet, and ElementsRegtest test-network values.
- Local integration testing uses Elements and Electrs; test configuration can also specify Esplora and Elements RPC endpoints.
- The README warns that the framework is at an extremely early development stage, with breaking changes and critical bugs expected.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Set up a Smplx project
Install the framework tooling, add its standard dependency, and initialize a project.
Before you start
- A Rust development environment with Cargo.
Steps
Install using the documented installer command: the command below.
curl -L https://smplx.simplicity-lang.org | bashRun
simplexup.Add the development dependency with the command below.
cargo add --dev smplx-stdInitialize a project with
simplex init.
Expected outcome
A new Smplx project initialized with the `smplx-std` development dependency.
Guide limitations
- The project requires a
simplex.tomlfile in the project root for framework use. - The README warns that the framework is at an extremely early stage and breaking changes and critical bugs are expected.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 9 October 2026
- Original website title
- BlockstreamResearch/smplx · Official homepage title · retained in its source language

