Structural analysis, in a browser tab.
An open structural-analysis platform. The solver runs on your machine:
nothing to install, no licences, no account.
Open the editor · Read the guide · Blog · Leer en español
Stabileo is structural analysis software that runs in any modern browser. You model, load, solve and read results in 2D and 3D. The analysis engine is written in Rust and compiled to WebAssembly, so it runs on your own computer: the model is not sent to a server to be solved.
It was born in the structures courses at FIUBA (University of Buenos Aires), and it keeps that origin: besides giving the answer, it shows the working: the degree of indeterminacy, the stiffness matrix step by step, which torsion theory applies to a section and why.
The interface is available in English, Spanish and Portuguese.
| Mode | Status | What it does |
|---|---|---|
| Basic | Available | Frame and truss structures in 2D and 3D. Axial, shear and moment diagrams, stresses, and advanced tools: kinematic analysis, section analysis, second order, buckling, modal analysis, plastic collapse, influence lines and the stiffness method step by step. Models load from Excel templates, save to a file or travel in a link. |
| PRO | In development | Finite elements and complex models: slabs and walls as plates and shells, constraints, code-based load generation, import from AutoCAD (DXF) or Excel, and dynamic, staged and non-linear analysis. |
| Education | In development | The teacher writes an exercise inside the app and hands it out as a link. The student solves it without the result in view and hands the answers back as a file or a short code. |
| Stabileo AI | In development | An agent being built to create, review and explain models, working on the same structured model and the same solver you use. The AI proposes; the solver decides. |
 |
 |
| Basic 2D: the moment diagram of a portal frame, with the results table. | Kinematic analysis: the degree formula says zero, the stiffness matrix finds the mechanism. |
The Stabileo guide explains how to use each mode and the theory behind it. It is written to be read like course notes, and you do not need to know GitHub or programming to follow it: open a chapter and use the links at the bottom of each page.
| English | Español | |
|---|---|---|
| Contents | Guide | Guía |
| 1 | Getting started | Primeros pasos |
| 2 | Basic mode in 2D | Modo Básico en 2D |
| 3 | Basic mode in 3D | Modo Básico en 3D |
| 4 | Advanced tools | Funciones avanzadas |
| 5 | PRO mode | Modo PRO |
| 6 | Theory | Fundamentos teóricos |
Technical and contributor documentation (solver reference, verification, benchmarks, roadmaps) is indexed in docs/README.md.
Many commercial structural analysis packages cost thousands of dollars a year, run on a single operating system, need installation and licence servers, and are closed source. Open-source solvers such as OpenSees are powerful, but they are driven by scripts and have no visual interface of their own.
- Local computation. The solver runs in your browser through WebAssembly. You open stabileo.com and start, with nothing to install and no model sent to a server.
- Live recalculation. With live calculation turned on, moving a node, changing a load or resizing a section solves the model again and updates the results.
- Explained results. The advanced tools lay out the formulas, the data and the intermediate steps. Kinematic analysis, section analysis and the step-by-step stiffness method show why a result is what it is, including when the formula you were taught does not apply.
- Open source. The engine and the interface are published under AGPL-3.0 and can be audited and modified.
Long pieces on how the solver works and the decisions behind it, in English, Spanish and Portuguese. Every figure in them is computed by the engine before the prose is written, and several posts embed the real editor on the model they describe. Two to start with:
- What free software computes, and what it does not explain: where the free tools stop
- The determinism boundary: why an AI agent must not do the arithmetic
Read all the posts on the blog →
- Engine: Rust, compiled to WebAssembly. Direct stiffness method for frames and trusses, MITC4 and DKT elements for plates and shells, sparse Cholesky factorisation for large models.
- Interface: Svelte 5 and TypeScript, Three.js for 3D, KaTeX for the step-by-step equations.
- Validation: checked against analytical solutions, NAFEMS benchmarks, the ANSYS Verification Manual, Code_Aster and textbook problems. See BENCHMARKS.md.
What the engine can solve
The engine implements more than any single mode exposes today; the modes above say what is reachable from the interface.
- 2D and 3D linear static, second order (P-Δ), linear buckling, modal, response spectrum, time history, harmonic response and moving loads
- Corotational and material non-linear analysis, plastic analysis, fibre beam-column elements
- Staged construction, prestress and post-tension, cables, contact and gap, non-linear soil-structure interaction
- Initial imperfections, residual stress, creep and shrinkage
- Shells: MITC4 (ANS + EAS-7), MITC9, SHB8-ANS solid-shell and curved shells
- Guyan and Craig-Bampton model reduction
- Load combinations, envelopes, section analysis, stress recovery and kinematic diagnostics
git clone https://github.com/lambdaclass/stabileo.git
cd stabileo/web
npm install
npm run wasm # build the Rust engine into web/src/lib/wasm (needs Rust and wasm-pack)
npm run dev # http://localhost:4000npm test # the web test suite
npm run build:only # production build -> web/dist/Requires Node.js 18 or later. npm run build also prerenders every public route by driving the
page in headless Chromium, so it needs npx playwright install chromium first; dev, test and
build:only do not.
Stabileo is built in the open, with the people who use it. Reports, ideas, discussions and code are all welcome.
The best place to start is our Discord: it is where we chat about the project, answer questions and discuss what comes next, in English and Spanish. Come and say hello.
Every channel is also gathered on linktr.ee/stabileo:
| Channel | Language | What for |
|---|---|---|
| Discord | English · Spanish | Chat and take part in the project |
| English · Spanish | Direct contact with the team | |
| X | English | News and updates |
| Spanish | New features as they ship | |
| Spanish | Project news |
Code. Pull requests are welcome. For larger changes, open an issue first to discuss the approach. The technical documentation is the place to start.
To report a vulnerability, email security@lambdaclass.com.
- Bautista Chesta: Civil Engineer (FIUBA), UX/UI and project management
- Diego Kingston: Ph.D. in Engineering (UBA), product–solver integration
- Federico Carrone: Founder of Lambda Class, solver lead
With contributions from mathematicians, physicists, computer engineers and computer scientists at Lambda Class.