REST API (other languages) | Boundary Documentation

Requires BAML version >=0.55

This feature is a preview feature and may change. Please provide feedback either in Discord or on GitHub so that we can stabilize the feature and keep you updated!

BAML allows you to expose your BAML functions as RESTful APIs:

We integrate with OpenAPI (universal API definitions), so you can get typesafe client libraries for free!

Install BAML VSCode Extension

https://marketplace.visualstudio.com/items?itemName=boundary.baml-extension

syntax highlighting
testing playground
prompt previews

Install NPX + OpenAPI

macOS (brew)

Linux (apt)

Linux (yum/dnf)

Windows

Other

$ brew install npm openapi-generator
> # 'npm' will install npx
> # 'openapi-generator' will install both Java and openapi-generator-cli

Add BAML to your existing project

This will give you some starter BAML code in a baml_src directory.

C#

C++

Go

Java

PHP

Ruby

Rust

Other

$ npx @boundaryml/baml init \
>   --client-type rest/openapi --openapi-client-type csharp

Start the BAML development server

$ npx @boundaryml/baml dev --preview

This will do four things:

serve your BAML functions over a RESTful interface on localhost:2024
generate an OpenAPI schema in baml_client/openapi.yaml
run openapi-generator -g $OPENAPI_CLIENT_TYPE in baml_client directory to generate an OpenAPI client for you to use
re-run the above steps whenever you modify any .baml files

BAML-over-REST is currently a preview feature. Please provide feedback either in Discord or on GitHub so that we can stabilize the feature and keep you updated!

Check that the server is running

After running the npx @boundaryml/baml dev command, you can check that the server is up and running by making an HTTP request to these routes:

http://localhost:2024/_debug/ping: Open in the browser or use curl to check that the server is up. You should see a text response similar to this: pong (from baml v0.206.1).
http://localhost:2024/docs: Open in the browser to see and interact with all your routes through the Swagger UI generated from the OpenAPI schema.

If using Docker, replace localhost with the container hostname or IP as appropriate.

Use a BAML function in any language!

openapi-generator will generate a README with instructions for installing and using your client; we’ve included snippets for some of the most popular languages below. Check out baml-examples for example projects with instructions for running them.

We’ve tested the below listed OpenAPI clients, but not all of them. If you run into issues with any of the OpenAPI clients, please let us know, either in Discord or by commenting on GitHub so that we can either help you out or fix it!

Go

Java

PHP

Ruby

Rust

Run this with go run main.go:

main.go

1 package main
2 
3 import (
4 	"context"
5 	"fmt"
6 	"log"
7   baml "my-golang-app/baml_client"
8 )
9 
10 func main() {
11 	cfg := baml.NewConfiguration()
12 	b := baml.NewAPIClient(cfg).DefaultAPI
13 	extractResumeRequest := baml.ExtractResumeRequest{
14 		Resume: "Ada Lovelace (@gmail.com) was an English mathematician and writer",
15 	}
16 	resp, r, err := b.ExtractResume(context.Background()).ExtractResumeRequest(extractResumeRequest).Execute()
17 	if err != nil {
18 		fmt.Printf("Error when calling b.ExtractResume: %v\n", err)
19 		fmt.Printf("Full HTTP response: %v\n", r)
20 		return
21 	}
22 	log.Printf("Response from server: %v\n", resp)
23 }