@vercel/kv

@vercel/kv

A client that works with Vercel KV.

Install

npm install @vercel/kv

Usage

import { kv } from '@vercel/kv';

// string
await kv.set('key', 'value');
let data = await kv.get('key');
console.log(data); // 'value'

await kv.set('key2', 'value2', { ex: 1 });

// sorted set
await kv.zadd(
  'scores',
  { score: 1, member: 'team1' },
  { score: 2, member: 'team2' }
);
data = await kv.zrange('scores', 0, 0);
console.log(data); // [ 'team1' ]

// list
await kv.lpush('elements', 'magnesium');
data = await kv.lrange('elements', 0, 100);
console.log(data); // [ 'magnesium' ]

// hash
await kv.hset('people', { name: 'joe' });
data = await kv.hget('people', 'name');
console.log(data); // 'joe'

// sets
await kv.sadd('animals', 'cat');
data = await kv.spop('animals', 1);
console.log(data); // [ 'cat' ]

// scan for keys
for await (const key of kv.scanIterator()) {
  console.log(key);
}

Custom Environment Variables

By default @vercel/kv reads the KV_REST_API_URL and KV_REST_API_TOKEN environment variables. Use the following function in case you need to define custom values

import { createClient } from '@vercel/kv';

const kv = createClient({
  url: 'https://<hostname>.redis.vercel-storage.com',
  token: '<token>',
});

await kv.set('key', 'value');

Automatic Deserialization

The default kv client automatically deserializes values returned from the database via JSON.parse. If this behaviour is undesired, create a custom KV client via the createClient method with automaticDeserialization: false. All data will be returned as strings.

import { kv, createClient } from '@vercel/kv';

const customKvClient = createClient({
  url: process.env.KV_REST_API_URL,
  token: process.env.KV_REST_API_TOKEN,
  automaticDeserialization: false,
});

await customKvClient.set('object', { hello: 'world' });

console.log(await kv.get('object')); // { hello: 'world' }
console.log(await customKvClient.get('object')); // '{"hello":"world"}'

Docs

See the documentation for details.

A note for Vite users

@vercel/kv reads database credentials from the environment variables on process.env. In general, process.env is automatically populated from your .env file during development, which is created when you run vc env pull. However, Vite does not expose the .env variables on process.env.

You can fix this in one of following two ways:

1. You can populate process.env yourself using something like dotenv-expand:

pnpm install --save-dev dotenv dotenv-expand

// vite.config.js
import dotenvExpand from 'dotenv-expand';
import { loadEnv, defineConfig } from 'vite';

export default defineConfig(({ mode }) => {
  // This check is important!
  if (mode === 'development') {
    const env = loadEnv(mode, process.cwd(), '');
    dotenvExpand.expand({ parsed: env });
  }

  return {
    ...
  };
});

1. You can provide the credentials explicitly, instead of relying on a zero-config setup. For example, this is how you could create a client in SvelteKit, which makes private environment variables available via $env/static/private:

import { createClient } from '@vercel/kv';
+ import { KV_REST_API_URL, KV_REST_API_TOKEN } from '$env/static/private';

const kv = createClient({
-  url: 'https://<hostname>.redis.vercel-storage.com',
-  token: '<token>',
+  url: KV_REST_API_URL,
+  token: KV_REST_API_TOKEN,
});

await kv.set('key', 'value');

FAQ

Does the @vercel/kv package support Redis Streams?

No, the @vercel/kv package does not support Redis Streams. To use Redis Streams with Vercel KV, you must connect directly to the database server via packacges like io-redis or node-redis.

import { createClient } from 'redis';

const client = createClient({
  url: process.env.KV_URL,
});

await client.connect();
await client.xRead({ key: 'mystream', id: '0' }, { COUNT: 2 });