Why does ClickMasters default to PostgreSQL?

UK GDPR compliance: PostgreSQL's native Row-Level Security (RLS) is the cleanest implementation of data isolation for multi-tenant UK GDPR compliant applications — each tenant's data is isolated at the database level, not the application level. JSONB: when you need flexible schema for some fields but relational integrity for others, JSONB eliminates the need for a separate document store. TimescaleDB: IoT and time-series data (energy monitoring, telemetry) extends PostgreSQL natively. Developer talent: the largest UK PostgreSQL talent pool.

When should I use MongoDB?

MongoDB is genuinely better for: content management systems where documents have highly variable structures, product catalogues where schema varies significantly between product types, and applications needing native geo-spatial queries at scale. For UK compliance: MongoDB Atlas has EU data regions and UK GDPR-compliant DPA. Multi-document transactions are available since MongoDB 4.0. However, for most UK web applications, PostgreSQL's JSONB covers the flexible data requirement without the operational overhead of a separate document store.

Postgresql Vs Mysql Vs Mongodb Uk

PostgreSQL vs MySQL vs MongoDB for UK Software Development — Honest Comparison (2025)

Updated: June 20259 min read

🇬🇧 UK Market💷 GBP📊 Comparison🔒 UK GDPR⚖️ UK Law

Direct Answer

PostgreSQL is the right default for most UK software projects: strongest compliance posture (row-level security for UK GDPR Article 25, JSONB for flexible data), excellent performance at scale, and the largest UK developer community. MySQL is fine for simple read-heavy applications but PostgreSQL has overtaken it for new UK projects. MongoDB suits genuinely document-centric data (content management, product catalogues) but adds operational complexity. ClickMasters defaults to PostgreSQL on all projects. Database choice is one of the most consequential early architecture decisions. Getting it wrong means painful migrations later. Here is an honest UK-market comparison based on what works in production.

Factor	PostgreSQL	MySQL	MongoDB
Data model	Relational + JSONB hybrid	Relational	Document (BSON)
UK GDPR Row-Level Security	✅ Native RLS (multi-tenant isolation)	Limited	Not native
ACID transactions	✅ Full ACID	✅ Full ACID	✅ Multi-document (v4.0+)
Schema flexibility	JSONB columns for flexible data	Rigid schema	Fully flexible
Full-text search	✅ Built-in (good for UK deployments)	Limited	✅ Good
Horizontal scaling	pgBouncer + read replicas	Read replicas	✅ Native sharding
AWS managed service	Amazon RDS / Aurora PostgreSQL	Amazon RDS MySQL / Aurora MySQL	Amazon DocumentDB (MongoDB-compatible)
TimescaleDB (IoT/time-series)	✅ Native extension	Not available	Not available
UK developer community	Very large	Large	Medium
ClickMasters default	✅ Yes — all projects	No	Only for document stores