Your stack has 7 services doing what Postgres already does for free.

Most stacks aren't designed. They accumulate.

Search gets Elasticsearch. Jobs get Redis. The AI feature gets Pinecone. Dashboards get piped into Snowflake. None of those calls were wrong on their own — they just never got revisited once the invoices started stacking up.

Just Use Postgres is a 24-page field manual that walks through eight of those calls and shows you exactly how to undo them, with runnable SQL for each one:

- 🗄️ JSONB + GIN → replace MongoDB

- ⚙️ SKIP LOCKED → replace Redis & RabbitMQ job queues

- 🔍 Full-text search + pg_trgm → replace Elasticsearch

- 🧠 pgvector + HNSW → replace Pinecone

- 🗺️ PostGIS → replace standalone GIS tools

- 📈 Partitioning + BRIN → replace InfluxDB

- 📊 Materialized views → replace Snowflake (for dashboards)

- 🔌 PostgREST + Row-Level Security → replace your hand-built API layer

Plus the part most "just use Postgres" hot takes skip: an honest module on exactly where this stops working, and a 5-phase rollout plan so you migrate without a 2am incident.

No fluff, no theory copy-paste SQL you can run today. Every recipe in this manual has been run against a real Postgres instance, not just written to look plausible.