Deno KV Has a Free Global Database API Built Into the Runtime

#deno #database #kv #serverless

Deno KV is a key-value database built directly into the Deno runtime. Zero setup, zero dependencies — just import and use. On Deno Deploy, it replicates globally.

Basic Usage

const kv = await Deno.openKv();

// Set a value
await kv.set(['users', 'alice'], { name: 'Alice', email: 'alice@example.com' });

// Get a value
const result = await kv.get(['users', 'alice']);
console.log(result.value); // { name: 'Alice', email: 'alice@example.com' }

// Delete
await kv.delete(['users', 'alice']);

Hierarchical Keys

// Users by ID
await kv.set(['users', userId], userData);

// Posts by user
await kv.set(['posts_by_user', userId, postId], postData);

// List all posts by user
const posts = kv.list({ prefix: ['posts_by_user', userId] });
for await (const entry of posts) {
  console.log(entry.key, entry.value);
}

Atomic Transactions

// Transfer money atomically
const sender = await kv.get(['accounts', senderId]);
const receiver = await kv.get(['accounts', receiverId]);

const result = await kv.atomic()
  .check(sender) // Ensure no concurrent modifications
  .check(receiver)
  .set(['accounts', senderId], { ...sender.value, balance: sender.value.balance - amount })
  .set(['accounts', receiverId], { ...receiver.value, balance: receiver.value.balance + amount })
  .commit();

if (!result.ok) console.log('Transaction failed — retry');

Queue (Built-in Job Queue)

// Enqueue a job
await kv.enqueue({ type: 'send-email', to: 'user@example.com', subject: 'Hello' });

// Process jobs
kv.listenQueue(async (msg) => {
  if (msg.type === 'send-email') {
    await sendEmail(msg.to, msg.subject);
  }
});

Watch for Changes

const stream = kv.watch([['config', 'feature-flags']]);
for await (const entries of stream) {
  console.log('Config changed:', entries[0].value);
}

Why This Matters

Zero setup: Built into Deno, no install needed
Global replication: On Deno Deploy, data in every region
ACID transactions: Atomic operations with optimistic concurrency
Built-in queue: Job processing without Redis or SQS
Free tier: 1GB storage on Deno Deploy

Need custom database tools or serverless backends? I build developer tools. Check out my web scraping actors on Apify or reach out at spinov001@gmail.com for custom solutions.

DEV Community