Launcher API

Endpoints

Typical flow

1. Build filters from /meta (cache it; it rarely changes).
2. Show a browser with /featured on open and /search as the user types, passing the instance's loader and game version so only compatible content shows.
3. Open a project with /project/{slug}. The description is Markdown; gallery is a list of image URLs.
4. Install: call /resolve with the instance's loader + version, download file.url, verify file.hashes.sha1, and save it to install.path inside the instance. Modpacks (install.method = "import_instance") are .mrpack/.zip files to feed your instance importer.
5. Update: hash the files in mods/, resourcepacks/, shaderpacks/ and POST them to /updates.

Example (JavaScript)

const API = "https://jace-store-deb.vercel.app/api/launcher/v1";
const instance = { loader: "fabric", game_version: "1.21.1" };

// 1. search
const res = await fetch(`${API}/search?${new URLSearchParams({ q: "minimap", type: "mod", ...instance })}`);
const { hits } = await res.json();

// 2. resolve + install
const r = await (await fetch(`${API}/project/${hits[0].slug}/resolve?${new URLSearchParams(instance)}`)).json();
const bytes = new Uint8Array(await (await fetch(r.file.url)).arrayBuffer());
const sha1 = [...new Uint8Array(await crypto.subtle.digest("SHA-1", bytes))].map(b => b.toString(16).padStart(2, "0")).join("");
if (r.file.hashes && sha1 !== r.file.hashes.sha1) throw new Error("hash mismatch");
// write bytes to <instance>/${r.install.path}

Example (Python)

import hashlib, pathlib, requests

API = "https://jace-store-deb.vercel.app/api/launcher/v1"
HEADERS = {"User-Agent": "MyLauncher/1.0"}
mods = pathlib.Path("~/.minecraft/mods").expanduser()

hashes = {hashlib.sha1(p.read_bytes()).hexdigest(): p for p in mods.glob("*.jar")}
r = requests.post(f"{API}/updates", headers=HEADERS, json={
    "hashes": list(hashes), "loader": "fabric", "game_version": "1.21.1",
}).json()

for h, info in r["results"].items():
    if info["update_available"]:
        f = info["latest_file"]
        print(f"{info['project']['title']}: {info['current_version']['version_number']} -> {info['latest_version']['version_number']}")
        data = requests.get(f["url"], headers=HEADERS).content
        assert hashlib.sha1(data).hexdigest() == f["hashes"]["sha1"]
        (mods / f["filename"]).write_bytes(data)
        hashes[h].unlink()