I'm building a mobile backend, should I use PostgreSQL or something else?

Usually: start with PostgreSQL.

For most mobile backends, PostgreSQL is the best default because it gives you:

• Strong consistency for user accounts, payments, orders, messages, etc.
• Flexible schema when your app changes quickly
• Great indexing and query support for feeds, search-ish queries, filtering, analytics-lite
• Mature ecosystem: backups, migrations, ORMs, monitoring, hosting
• JSON support if you need semi-structured data without jumping to NoSQL

When PostgreSQL is a strong fit

Use Postgres if your backend has:

• user profiles and authentication
• subscriptions or purchases
• chat/messages
• content feeds
• admin dashboards
• relational data with joins
• moderate to high traffic, but not extreme scale needs yet

When you might want something else

1. Firestore / DynamoDB / MongoDB

Consider a document database if:

• your data is mostly document-shaped
• you want very fast development with fewer joins
• your access patterns are simple and known ahead of time
• you expect massive horizontal scale and are okay designing around the DB’s constraints

Tradeoffs:

• more awkward querying for complex relationships
• denormalization can get messy
• consistency and transactions are often trickier than with Postgres

2. Redis

Use Redis for:

• caching
• rate limiting
• ephemeral sessions
• queues / pub-sub

Not as your primary system of record.

3. Elasticsearch / OpenSearch

Use for:

• full-text search
• advanced filtering/search experiences

Not as your primary database.

4. CockroachDB / YugabyteDB

If you need:

• Postgres-like SQL
• multi-region distribution
• more resilience across regions

But they add complexity. For most mobile apps, plain Postgres is enough.

Practical recommendation

A common and very effective setup is:

• PostgreSQL as your primary DB
• Redis for caching and ephemeral data
• optional object storage for images/videos/files
• optional search engine later if needed

Rule of thumb

If you’re unsure, choose PostgreSQL unless you have a very specific reason not to.

If you want, I can help you choose based on your app type. For example:

• social app
• marketplace
• chat app
• fitness app
• delivery app
• SaaS/mobile CRM

If you tell me your app’s main features and expected traffic, I can recommend a concrete stack.