LibrePCB Developers Documentation
Server API Specification

LibrePCB provides an API at which is used by the LibrePCB application, for example to fetch the latest libraries.

The API uses JSON for responses.


An API URL consists of following parts:

Part Description Example
<BASE> Base URL of API server
/api Base path of API /api
/<VERSION> API version number /v1
/<RESOURCE> Path to the requested resource /libraries/v0.1

The base URL of the official API server is, but for your own API server you can use any other base URL. This is the URL which must be specified in the workspace settings of LibrePCB.

Currently the only available API version is v1, but in future there might be newer API specifications available with higher version numbers. Because the version number is part of the URL, a server could support multiple API versions at the same time.


Request the list of libraries:

curl ''


In order to get the response in the user's language, the client may set the HTTP header Accept-Language to the desired locale string (e.g. de_DE).


The API uses pagination (i.e. splitting large responses across several shorter responses) to keep the response time of requests short.

A paginated response contains following JSON entries:

Key Type Description
count integer Total count of results over all pages
next string URL of next page (null for last page)
previous string URL of previous page (null for first page)
results list The actual response objects


Here an example how a paginated response looks like:


curl ''


"count": 42,
"next": "",
"previous": null,
"results": [

Available Resources

Following resources are available:

Path Description
/libraries Fetch list of available libraries
/order Upload a project to start ordering it


The resource path /libraries is used to fetch the list of all available libraries. It is used in the LibrePCB Library Manager to list and download libraries.

The file format version of the application needs to be appended to the path to fetch only libraries with compatible file format. For example if the application uses file format version 0.1, use the path /api/v1/libraries/v0.1. Note that the response can still contain libraries with a file format older than the specified one. But it will never contain libraries with a newer file format.

The response is a list of objects with following properties:

Name Type Description
uuid string UUID of the library (from library.lp)
name object Library name, multilingual (from library.lp)
description object Library description, multilingual (from library.lp)
keywords object Library keywords, multilingual (from library.lp)
author string Author of the library (from library.lp)
version string Version of the library (from library.lp)
deprecated boolean Deprecated flag (from library.lp)
url string URL of library (from library.lp)
dependencies list List of dependent library UUIDs (from library.lp)
component_categories integer Count of contained component categories
package_categories integer Count of contained package categories
symbols integer Count of contained symbols
packages integer Count of contained packages
components integer Count of contained components
devices integer Count of contained devices
recommended boolean Whether the library is recommended to install
updated_at string ISO 8601 datetime of last update
format_version string File format of the library (from .librepcb-lib)
icon_url string URL to library icon (null if N/A)
download_url string URL to file for downloading the library (*.zip)
download_size integer Size of file to download in bytes (null if unknown)
download_sha256 string SHA256 of file to download (null if unknown)



curl ''

Response (without pagination):

"uuid": "e3ce49bf-e959-4092-8b48-aeead756f8d1",
"name": {
"default": "Molex",
"en_US": "Molex"
"description": {
"default": "Connectors, Sockets and more"
"keywords": {
"default": "connector,molex"
"author": "LibrePCB",
"version": "0.0.1",
"deprecated": false,
"url": "",
"dependencies": [
"component_categories": 13,
"package_categories": 37,
"symbols": 123,
"packages": 321,
"components": 42,
"devices": 0,
"recommended": false,
"updated_at": "2018-04-13T12:43:52Z",
"format_version": "0.1",
"icon_url": "",
"download_url": "",
"download_size": null,
"download_sha256": null,

Order PCB

The resource path /order is used to upload a LibrePCB project to start ordering the PCB. After the project has been uploaded, the order process needs to be continued in the web browser.

The client has to initiate the order with a GET request to the path /order. The response is a JSON object with the following data (no pagination used):

Name Type Description
info_url string URL pointing to service information (e.g. privacy policy)
upload_url string URL where the project has to be uploaded
max_size integer Maximum allowed size (in bytes) of the uploaded project


  • The info_url should be short and descriptive to allow displaying it as-is in the LibrePCB GUI.
  • If the service is (temporarily) not available, upload_url can be set to an empty string or null. LibrePCB shall then display a message like "Service is currently not available, please try again later".
  • The max_size applies to the raw *.lppz file without base64 encoding, so the actually uploaded JSON object can be much larger. LibrePCB shall not start the upload if the project is larger than this value.

Afterwards, the client has to make a POST request to the received upload_url with a JSON object containing the following data:

Name Type Description
project string The whole project as a Base64 encoded *.lppz archive
board string The filepath of the board to be ordered (null if unknown)

The response is a JSON object with the following data (no pagination used):

Name Type Description
redirect_url string URL to continue the order process in the web browser


Initial Request:

curl -H "Content-Type: application/json" \

Initial Response:

"info_url": "",
"upload_url": "",
"max_size": 100000000

Upload Request:

curl -X POST -H "Content-Type: application/json" \
-d '{"project": "...", "board": "boards/default/board.lp"}' \

Upload Response:

"redirect_url": ""