Building with Edge KV

2026-03-12 · GitFlare Engineering

Edge KV is eventually consistent. A write from NRT is readable in NRT immediately and in other colos within a couple of seconds. That is enough for session blobs, feature flags, and HTML fragments. It is the wrong tool for a bank ledger.

Write from a Worker

export default {
  async fetch(request, env) {
    if (request.method === "POST") {
      const sid = crypto.randomUUID();
      await env.SESSIONS.put(sid, await request.text(), { expirationTtl: 1800 });
      return new Response(null, { status: 204, headers: { "set-cookie": `sid=${sid}; Path=/; HttpOnly; Secure` } });
    }
    const sid = request.headers.get("cookie")?.match(/sid=([^;]+)/)?.[1];
    const session = sid ? await env.SESSIONS.get(sid) : null;
    return new Response(session || "{}", { headers: { "content-type": "application/json" } });
  },
};

Create the namespace

$ gitflare kv namespace create SESSIONS
$ gitflare kv put SESSIONS welcome '{"v":1}' --ttl 3600
$ gitflare kv get SESSIONS welcome

Keys are UTF-8, up to 512 bytes. Values are 25 MiB on paid plans. List is paginated; see the 2026-06-02 changelog for cursor.

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