PostgreSQL vs MongoDB vs SQLite: Picking a Database in 2026

TL;DR#

• PostgreSQL — our default for most projects. ACID, JSONB, RLS, built-in full-text search.
• MongoDB — when the schema truly is dynamic (CMS, content stores), distributed sharding.
• SQLite — embedded, edge, replicated with Litestream/LiteFS. Increasingly valid for production small-to-mid SaaS.

Performance — Insert + simple-query workload#

Single instance, basic schema, no network round-trip. Real workloads can differ wildly.

Feature matrix#

Feature	PostgreSQL	MongoDB	SQLite
ACID transactions	✅	✅ (since 4.0)	✅
JSON/document	✅ JSONB indexable	✅ native BSON	✅ JSON1 ext
Full-text search	✅ tsvector	✅ text indexes	✅ FTS5
Row-Level Security	✅	❌ (app-level)	❌ (app-level)
Geospatial	✅ PostGIS	✅ 2dsphere	✅ R*Tree
Replication	✅ logical + physical	✅ replica set	✅ Litestream / LiteFS
Sharding	manual partitioning / Citus	✅ native	n/a (single file)
Embedded	❌	❌	✅

When to pick PostgreSQL#

• Standard SaaS with many relationships.
• SQL-based reporting + analytics.
• Multi-tenant with Row-Level Security.
• Mixed workloads (transactions + analytics).
• Our default for most projects.

When to pick MongoDB#

• Truly dynamic schema (CMS user-generated content, comment trees).
• Document-heavy (embedded sub-documents, no joins needed).
• Horizontal scale from day one (native sharding).
• Team familiar with the JS/JSON ecosystem.

Note: MongoDB is often “adopted because trendy”, but most use cases actually fit PostgreSQL JSONB. When in doubt, start with Postgres — far more flexible later.

When to pick SQLite — the underrated choice#

In 2026 SQLite is increasingly valid for production SaaS because:

1. Litestream / LiteFS for live replication to S3-compatible object stores.
2. WAL mode allows many concurrent readers + 1 writer — enough for 90% of small-to-mid SaaS.
3. No network round-trip — the DB is on the same disk as the app. Microsecond latency.
4. Easy backups — copy a file. No pg_dump ritual.
5. MIT-style licensing — clean.

Modern tools that make SQLite production-ready:

• Turso — managed SQLite with global edge replicas.
• Cloudflare D1 — SQLite in an edge worker.
• Litestream — backup + replication to S3.
• LiteFS (Fly.io) — distributed SQLite.

Best for: multi-tenant SaaS with one DB per tenant, edge apps, fast prototypes.

Lancartech’s choices#

Use case	Pick
Lancartech Billing	PostgreSQL
Tokora multi-tenant e-commerce	PostgreSQL + RLS
Splay API content cache	PostgreSQL JSONB
Internal admin tooling	SQLite + Litestream
Edge-worker key-value	Cloudflare KV or D1
Time-series metrics	PostgreSQL + TimescaleDB or ClickHouse
Logging	ClickHouse or Loki

Rule of thumb#

Default to PostgreSQL. Consider SQLite for small SaaS + edge. MongoDB only if the schema is truly dynamic and the team is already expert.

Database architecture consult.