baml
BAML is a statically-typed programming language built for AI agents, combining TypeScript-like syntax with Rust-level type safety and runtime type persistence. It runs standalone or integrates with Python, TypeScript, Go, and other languages, designed to reduce agent mistakes through structural constraints.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | BoundaryML/baml |
| Owner | BoundaryML |
| Primary language | Rust |
| License | Apache-2.0 — OSI-approved |
| Stars | 8.5k |
| Forks | 442 |
| Open issues | 249 |
| Latest release | baml-language-0.13.1-nightly.20260707.f (2026-07-07) |
| Last updated | 2026-07-08 |
| Source | https://github.com/BoundaryML/baml |
What baml is
BAML is a compiled language written in Rust that enforces static typing, colorless concurrency (Go-style), and typed error handling with no `any` type escape hatch. Types and errors are statically analyzed and persist at runtime; the filesystem defines module structure.
Get the baml source
Clone the repository and explore it locally.
git clone https://github.com/BoundaryML/baml.gitcd baml# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Requires learning a new language syntax and toolchain; teams must establish compilation and type-checking into CI/CD pipelines.
- Multi-language integration (Python, TypeScript, Go) requires code generation and FFI bindings; test coverage across language boundaries is essential.
- Static typing and error contracts demand upfront schema design; refactoring type signatures can cascade across agent implementations.
- Nightly releases (0.13.1-nightly.20260707) suggest active development; production use may encounter breaking changes or incomplete features.
- Module resolution via filesystem structure differs from conventional package managers; teams must align on directory conventions.
When to avoid it — and what to weigh
- Rapid Prototyping with Dynamic Typing — If your team prioritizes speed-to-MVP with minimal boilerplate, BAML's static type system and compilation step add friction compared to Python/JavaScript scripting.
- Existing Mature Agent Frameworks — Migrating from LangChain, AutoGPT, or similar frameworks to a new language ecosystem is costly; BAML adoption requires rewriting agent logic rather than augmenting existing stacks.
- Small Teams or Hobby Projects — BAML's compile-time discipline and multi-language FFI are overkill for solo developers or small projects where informal testing and loose typing suffice.
- Vendor Lock-in Concerns — BAML is an emerging proprietary language by Boundary; teams requiring long-term portability may hesitate to invest in a non-standard, single-vendor tool without guarantees of continuity.
License & commercial use
BAML is licensed under Apache License 2.0 (Apache-2.0), a permissive open-source license that allows commercial use, modification, and redistribution with attribution and liability disclaimers.
Apache-2.0 permits commercial deployment and proprietary extensions without royalties. However, Boundary (the vendor) may offer commercial support, hosted services, or closed-source tooling; review their commercial terms separately. No restrictions on using BAML in production commercial systems are evident from the license alone.
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Active |
| Documentation | Adequate |
| License clarity | Clear |
| Deployment complexity | Moderate |
| DEV.co fit | Good |
| Assessment confidence | High |
BAML enforces static typing and error handling at compile time, reducing runtime surprises and injection vectors. No security audits, vulnerability disclosures, or threat model are mentioned. Teams should review: (1) type system completeness against common agent attack vectors (prompt injection via untyped fields), (2) code generation correctness for FFI bindings, (3) sandboxing/isolation if running untrusted agent code. No exploit details available from public data.
Alternatives to consider
LangChain / LangGraph
Mature, multi-language agent frameworks with extensive LLM integrations; trade type safety for ecosystem maturity and community plugins.
Pydantic (Python) + FastAPI
Lightweight, Python-native validation and serialization for agent I/O; suitable for teams already in Python, lacking BAML's compile-time guarantees.
Prompt Engineering Frameworks (Claude API, OpenAI Function Calling)
Vendor-native structured outputs reduce need for custom type contracts; lock-in to a single LLM provider but minimal custom tooling.
Build on baml with DEV.co software developers
BAML enforces agent contracts at compile time, reducing runtime failures. Explore the quickstart, join the Discord community, or contact Boundary for enterprise support.
Talk to DEV.coRelated open-source tools
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baml FAQ
Can I use BAML in production?
Do I have to learn a new language?
How does BAML compare to OpenAI's Function Calling or Claude's tool use?
Is Boundary's commercial support required?
Work with a software development agency
DEV.co helps companies turn open-source tools like baml into production software. Our software development services cover the full lifecycle — architecture, web development, integration, and maintenance — delivered by software developers and web developers who ship. Engage our software development agency to implement or customize it for your ai frameworks stack.
Ready to Build Type-Safe Agents?
BAML enforces agent contracts at compile time, reducing runtime failures. Explore the quickstart, join the Discord community, or contact Boundary for enterprise support.