Getting the SDK

Download the SDK from our website or API.

Ultralight ships for various targets as a prebuilt 7-Zip package. You can download the latest SDK release from our website or API.

📘 Build Prerequisites

Make sure to setup your build environment before using the SDK in your applications.

#Downloading from the Website

Visit our download page to get the latest SDK for your platform.

Our Free SDK is available for all developers, make sure to login to access paid SDKs if you have purchased a license.

#Downloading from the API

You can also download SDK packages over HTTP using our API (great for automating downloads or bootstrapping CI scripts).

#API Endpoints

All endpoints live under https://ultralig.ht. They need no credentials and serve the Free edition on their own; add an API key to the same requests and they serve everything your account can download.

📘 One script for every account

The endpoints are the same with or without a key, so a script written for the Free edition needs nothing but the key added to download a paid edition.

#API Keys

#Creating a Key

Create a key on the API Keys page of your dashboard. Any account can, including free ones. Give it a name and a lifetime, then copy it: it is shown once.

🚧 Keep keys confidential

A key can download everything your account can. Store it in your build system's secret store, never in a repository, and revoke it from the same page if it leaks.

#Using a Key

Pass it in the Authorization header:

curl -H "Authorization: Bearer $ULTRALIGHT_API_KEY" \
  "https://ultralig.ht/api/v1/sdk/releases"

🚧 A key that fails is refused

A request that sends an expired or revoked key gets a 401, never the Free edition in its place. Only a request with no Authorization header at all is treated as anonymous.

#Listing Packages

Ask for the list to see which versions and platforms you can download:

curl "https://ultralig.ht/api/v1/sdk/releases"

{
  "data": [
    {
      "version": "2.0.0",
      "channel": "stable",
      "platform": "linux-x64",
      "edition": "free",
      "build": "release",
      "filename": "ultralight-sdk-2.0.0-linux-x64.7z",
      "sha256": "…"
    }
  ]
}

The list has one entry per package file, newest release first. With a key it includes every edition your account can download.

#Stable and Dev Channels

Each release is on the stable channel or the dev channel. Dev releases carry fixes and features ahead of the next stable release.

📘 latest means the newest stable release

A dev release is never picked by default. Add channel=dev to get the newest dev release, or name a dev release's version.

#Downloading Packages

#The Newest Stable Release

Pass a platform from the list:

curl -L -o ultralight-sdk.7z \
  "https://ultralig.ht/api/v1/sdk/download?platform=linux-x64"

#The Newest Dev Release

Add channel=dev:

curl -L -o ultralight-sdk.7z \
  "https://ultralig.ht/api/v1/sdk/download?platform=linux-x64&channel=dev"

#A Specific Release

Add its version, stable or dev:

curl -L -o ultralight-sdk.7z \
  "https://ultralig.ht/api/v1/sdk/download?platform=linux-x64&version=2.0.0"

#A Paid Edition

With a key, the same request gives you the highest edition your account holds. Add edition to pick another:

curl -L -H "Authorization: Bearer $ULTRALIGHT_API_KEY" -o ultralight-sdk.7z \
  "https://ultralig.ht/api/v1/sdk/download?platform=windows-x64&edition=pro"

📘 Name the edition in scripts

A request that names a paid edition without a key is refused with a 401, so a CI job whose key is missing fails at once instead of quietly building against the Free edition.

🚧 Some clients forward your key

A download redirects to a signed link on another host. wget and curl --location-trusted send the Authorization header along to it. With those clients, request the link with format=json (below) and fetch it in a second request that carries no key.

#Verifying Packages

Add format=json to get the download link together with the package's SHA-256 checksum instead of the file:

curl "https://ultralig.ht/api/v1/sdk/download?platform=linux-x64&format=json"

{
  "url": "https://…",
  "version": "2.0.0",
  "platform": "linux-x64",
  "filename": "ultralight-sdk-2.0.0-linux-x64.7z",
  "sha256": "…",
  "expires_in": 300
}

Fetch the url, then compare the checksum before you unpack:

shasum -a 256 ultralight-sdk.7z

certutil -hashfile ultralight-sdk.7z SHA256

📘 The link expires

expires_in is in seconds. Fetch the url within five minutes of asking for it, or ask again.

#Full API Reference

#Conventions

#List Packages

GET /api/v1/sdk/releases

Every package you can download, newest release first, one entry per file. Without a key: every Free package of every published release.

Rate limit: 60 requests an hour per address without a key; 120 requests an hour per key with one.

#Download a Package

GET /api/v1/sdk/download

#Query Parameters

#Response

Without format=json: a 302 redirect to a signed link that expires five minutes after it is issued.

With format=json:

#Rate Limits

#Errors

#Package Contents

Along with the folders below, the package root contains a README, a VERSION.txt file tracking the release version, and a root CMakeLists.txt for building the bundled samples and tools.

For details on which runtime binaries and resource assets your application must bundle and deploy, see Linking to the Library.