Does Redis Work With PlanetScale?
Redis and PlanetScale work together seamlessly as complementary layers—Redis handles caching and sessions while PlanetScale serves as your persistent database.
Quick Facts
How Redis Works With PlanetScale
Redis and PlanetScale are architectural complements rather than direct integrations. PlanetScale provides your primary MySQL-compatible relational database with features like branching and serverless scaling, while Redis sits in front as a caching layer or session store. This is a standard pattern: write-through or write-behind caches populate Redis from PlanetScale queries, dramatically reducing database load and latency. The developer experience is straightforward—you manage two separate connections in your application, typically querying Redis first for cache hits, then falling back to PlanetScale on misses. For session management, Redis excels at storing user sessions that PlanetScale would handle inefficiently. The serverless nature of both platforms pairs well; you can auto-scale each independently based on demand. PlanetScale's branching feature is unaffected by Redis presence, and you can safely test cache logic on development branches before production deployment.
Best Use Cases
Quick Setup
npm install redis mysql2 dotenvimport redis from 'redis';
import mysql from 'mysql2/promise';
const redisClient = redis.createClient({ url: process.env.REDIS_URL });
const pool = mysql.createPool({ uri: process.env.DATABASE_URL });
async function getUser(userId: string) {
const cached = await redisClient.get(`user:${userId}`);
if (cached) return JSON.parse(cached);
const conn = await pool.getConnection();
const [rows] = await conn.query('SELECT * FROM users WHERE id = ?', [userId]);
conn.release();
if (rows.length > 0) {
await redisClient.setEx(`user:${userId}`, 3600, JSON.stringify(rows[0]));
return rows[0];
}
return null;
}
await redisClient.connect();Known Issues & Gotchas
Cache invalidation becomes critical—stale data in Redis won't automatically sync when PlanetScale records change
Fix: Implement explicit cache invalidation on writes, use TTLs religiously, or adopt cache-aside patterns with versioning
PlanetScale's connection limits are strict; if Redis misses cause thundering herds of PlanetScale queries, connection pools will exhaust
Fix: Use connection pooling on the PlanetScale client, implement exponential backoff on cache misses, and monitor connection usage
Redis is ephemeral by default—data loss on restart means you must treat it as cache-only, never sole source of truth
Fix: Always keep authoritative data in PlanetScale; use Redis persistence (RDB/AOF) only if you self-host, otherwise treat as disposable
Billing complexity—you're paying for both services independently with no bundled discounts
Fix: Evaluate Redis-as-a-service providers (Upstash, AWS ElastiCache) based on total cost of ownership alongside PlanetScale fees
Alternatives
- •PlanetScale Query Cache + Memcached (query caching built into PlanetScale with alternative cache backend)
- •DynamoDB + ElastiCache (AWS-native equivalent with DynamoDB as NoSQL primary store)
- •Neon (PostgreSQL) + Valkey (Redis fork, newer alternative)
Resources
Related Compatibility Guides
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