Using Cloudflare Workers KV for Simple Key-Value Storage

Workers KV is a globally replicated key-value store built into Cloudflare. It’s eventually consistent and optimized for read-heavy workloads — a good fit for config, feature flags, or cached content.

Setting up

Create a namespace via the Cloudflare dashboard or Wrangler:

wrangler kv namespace create MY_STORE

Bind it in wrangler.toml:

[[kv_namespaces]]
binding = "MY_STORE"
id = "abc123..."

Reading and writing

export default {
  async fetch(request: Request, env: Env) {
    // Write
    await env.MY_STORE.put('greeting', 'hello');

    // Read
    const value = await env.MY_STORE.get('greeting');
    return new Response(value ?? 'not found');
  },
};

Things to keep in mind

• Eventual consistency: writes propagate globally within ~60 seconds. Don’t use KV where you need immediate read-after-write consistency.
• Size limits: values up to 25 MB, keys up to 512 bytes.
• Reads are free at the edge: KV is great for data you write infrequently but read constantly.

For strong consistency, look at Durable Objects instead.