Firebase vs PlanetScale: NoSQL Platform vs MySQL

Firebase and PlanetScale represent fundamentally different approaches to building applications. Firebase is Google's all-in-one app platform — it bundles Firestore (a NoSQL document database), Authentication, Hosting, Cloud Functions, and more into a single cohesive service. You get everything out of the box, but you're working within Google's ecosystem and document-based data model. PlanetScale, by contrast, is a serverless MySQL database with a developer-friendly branching workflow inspired by Git. It does one thing — relational data storage — but it does it exceptionally well. There's no auth, no hosting, no functions; just a fast, scalable MySQL-compatible database you can query with standard SQL. Understanding this distinction is the key to making the right choice: Firebase is a platform, PlanetScale is a database.

Firebase's Spark (free) plan includes generous limits — 1GB Firestore storage, 50K daily reads, 20K daily writes, and 10 active functions. The Blaze (pay-as-you-go) plan scales with usage and can become expensive if your Firestore query patterns aren't optimised. A common mistake is running unbounded queries that trigger thousands of reads, leading to surprise bills. PlanetScale's Hobby tier offers 5GB storage, 1 billion row reads, and 10 million row writes per month at no cost. Paid plans start at $39/month per database and scale predictably. PlanetScale's pricing is generally more transparent for read-heavy workloads. For write-heavy applications, compare carefully — Firebase's per-write costs can add up. The key hidden cost to watch for with Firebase is Firestore reads triggered by real-time listeners and compound query indexing requirements.

Firebase's Firestore scales automatically and handles millions of concurrent connections well, making it excellent for real-time applications like chat and collaborative tools. However, its NoSQL nature means certain query patterns are simply impossible — you cannot do arbitrary joins, aggregations require workarounds, and complex relational queries need data denormalisation. PlanetScale uses Vitess under the hood — the same technology that powers YouTube and GitHub — enabling horizontal sharding at massive scale while maintaining full MySQL compatibility. This means you can run any SQL query you'd run on a standard MySQL database, and PlanetScale will handle the scaling transparently. For SaaS applications with complex data models, PlanetScale's approach is more scalable long-term because you aren't constrained by a document model.

Firebase has a mature SDK ecosystem with excellent mobile support (iOS, Android, Flutter) and solid web libraries. The Firebase console provides a visual database explorer, emulator suite for local development, and integrated monitoring. The main friction points are the emulator suite's complexity and the learning curve around Firestore security rules. PlanetScale offers an outstanding developer experience centred on its CLI and branching workflow. You can create a development branch, run migrations, preview the schema diff, and merge — all with the same mental model as Git. It works seamlessly with Prisma and Drizzle ORM, making TypeScript projects feel natural. The PlanetScale console is clean and fast. If you're building a Next.js or Node.js application, PlanetScale with Prisma is a particularly smooth developer experience.

Firebase vendor lock-in is a legitimate concern. Firestore's query model, security rules, and SDK are proprietary — there's no easy path to migrate to another database without rewriting significant application logic. Your data is in a document format tied to Google's infrastructure, and there's no standard export format that maps cleanly to relational databases. PlanetScale uses standard MySQL, which means your data and queries are portable. You can migrate to any MySQL-compatible database (AWS RDS, PlanetScale, self-hosted MySQL) with minimal changes. This portability is valuable as a long-term hedge. If you're building something where data ownership and migration flexibility matter, PlanetScale's open standard approach is the safer choice. For applications where Firebase's ecosystem provides clear value (mobile, real-time), the lock-in trade-off is often worth it.

Choose Firebase when building a mobile app that needs offline sync, a real-time collaborative tool like a shared document or whiteboard, or an MVP where speed to market matters and you want auth bundled in. Firebase also shines for notification-heavy apps and anything requiring live data updates without polling. Choose PlanetScale for SaaS applications with complex data relationships — multi-tenancy, billing, user roles, and anything requiring SQL joins. E-commerce platforms with inventory, orders, and customers are a natural fit for relational data. Content platforms can go either way depending on whether you need relational content modelling. Many teams successfully use Firebase Auth alongside PlanetScale for data storage — getting the best of both: easy authentication from Firebase and flexible relational queries from PlanetScale.