Catalog hydration - egdata API Docs

Use POST /catalog/hydrate when a client needs the records related to catalog identifiers it has discovered. The endpoint returns newline-delimited JSON (application/x-ndjson), with one result line per requested root.

const response = await fetch("https://api.egdata.app/catalog/hydrate", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    schemaVersion: 2,
    identifiers: [
      { type: "asset", namespace: "example-namespace", artifactId: "ExampleGame", platform: "Windows" },
    ],
    knownRoots: [],
    knownRecords: [],
  }),
});

if (!response.ok || !response.body) throw new Error(`Hydration failed: ${response.status}`);
const reader = response.body.pipeThrough(new TextDecoderStream()).getReader();
let pending = "";
while (true) {
  const { value, done } = await reader.read();
  pending += value ?? "";
  const lines = pending.split("\n");
  pending = lines.pop() ?? "";
  for (const line of lines) if (line) console.log(JSON.parse(line));
  if (done) break;
}
if (pending) console.log(JSON.parse(pending));

Send up to 25 unique composite item, platform-qualified asset, or platform-qualified release-app identifiers. The request uses schema version 2 and may include knownRoots and up to 5,000 knownRecords to request only changes. The whole request is limited to 256 KiB.

Each line reports one root as resolved, unchanged, not-found, or error. A resolved result contains record membership and records whose hashes changed. An unchanged result confirms the root is current. A not-found result clears only that root. An error is isolated to that root; keep its local data and retry it. Process each line independently so a failed or interrupted stream does not discard earlier results.

{"schemaVersion":2,"rootKey":"asset:example-namespace:examplegame:windows","identifier":{"type":"asset","namespace":"example-namespace","artifactId":"ExampleGame","platform":"Windows"},"hydratedAt":"2026-09-30T10:00:00.000Z","status":"unchanged","graphHash":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"}

Each line is bounded to 2 MiB and 500 records. A resolved graph can include linked offers, related items, assets, and normalized release apps. Prices, price history, build history, signed URLs, and image binaries are excluded. See the API reference for the complete request and response schemas.