1. Three engines, three approaches: a quick overview
MySQL: popular by habit
MySQL has been tied to web development for decades. It became popular through WordPress, Joomla and thousands of PHP projects. It is easy to configure, well documented and supported by practically every hosting provider.
That simplicity is also its limit. When you need complex queries, advanced data types or full ACID compliance, MySQL starts to fall behind PostgreSQL. Since Oracle acquired MySQL in 2010, parts of the open-source community have also questioned its direction and licensing.
In custom CRM and ERP systems, MySQL often stops being enough once a project needs advanced reporting, complex relationships between tables or several kinds of data in one database. That is the situation in which companies most often move to PostgreSQL.
MongoDB: flexibility at the cost of consistency
MongoDB is a NoSQL document database that took off during the startup boom and the era of rapid prototyping. It stores data in a JSON-like format, so JavaScript developers find it easy to work with. It doesn't need a rigid schema: you can add fields on the fly, without migrations.
The problems show up as a project matures. With no enforced schema, data becomes inconsistent. Full ACID transactions arrived only in later versions and still don't match relational databases in every scenario. MongoDB also lost ground in the Stack Overflow 2025 survey, and a growing number of companies have published write-ups of their move from MongoDB to PostgreSQL.
Then there is the SSPL (Server Side Public License), which MongoDB Inc. created to stop competitors from selling services built on MongoDB. For companies that care about licensing freedom and independence from a vendor, this is a real risk.
PostgreSQL: the standard for the years ahead
PostgreSQL is an object-relational database that a global open-source community has developed for over 35 years. It offers full SQL standard compliance, advanced data types (including JSONB, vectors and geospatial data), over 390 extensions and reliability proven by some of the world's largest technology companies.
According to the Stack Overflow Developer Survey 2025, PostgreSQL is the most widely used database among professional developers at 55.6%, more than 15 percentage points ahead of MySQL (40.5%). In the enterprise segment the gap is 18.6 pp.
2. Why PostgreSQL wins: concrete business advantages
Scalability proven by OpenAI
The strongest proof of PostgreSQL's scalability is OpenAI's infrastructure. The company behind ChatGPT, a platform with over 800 million users, runs its primary database on a single PostgreSQL instance with nearly 50 geographically distributed read replicas. The system handles millions of queries per second, with p99 latency in the low double-digit milliseconds and 99.999% availability.
This is not an experiment. It is the production environment of the world's largest AI platform. OpenAI's engineers have stressed that staying on PostgreSQL instead of moving to distributed databases was a deliberate choice based on analysis of the workload, not on trends.
Data integrity you can rely on
For CRM and ERP systems, data integrity comes first. PostgreSQL offers full ACID compliance, advanced locking, Row Level Security and a rich constraint system. In practice, your financial data, customer relationships and business processes are protected at every step of every operation.
MySQL offers ACID only with the InnoDB engine, and MongoDB added full multi-document transactions only in version 4.0. There are still scenarios where these mechanisms behave differently than in mature relational databases.
Ready for AI
Thanks to the pgvector extension, PostgreSQL can store and search vectors, a key technology for AI applications. Instead of running a separate vector database (Pinecone or Weaviate, for example), you can keep AI embeddings next to your business data: in one system, in one transaction, with no synchronisation between databases.
This matters for companies planning intelligent search, recommendation systems or chatbots built on their own data.
An ecosystem of extensions instead of extra tools
PostgreSQL has over 390 extensions that handle geospatial data (PostGIS), time series (TimescaleDB), full-text search, JSONB data and much more, all inside one database. You don't have to maintain several separate systems, so the infrastructure stays simpler.
As one industry analyst put it, three separate systems at 99.9% availability each give a combined availability of 99.7%. That is 26 hours of downtime a year instead of 8.7. Every extra system multiplies the risk of failure.
3. Side-by-side comparison: which database for which project
Criterion PostgreSQL MySQL MongoDB Type Relational (object-relational) Relational Document (NoSQL) ACID compliance Full, native InnoDB only From v4.0, limited JSON support JSONB with full indexing Basic Native (BSON) Read scalability Replicas, proven (OpenAI: 50 replicas) Replicas Native sharding AI vectors pgvector (built in) No native support Atlas Vector Search Geospatial data PostGIS (industry standard) Basic functions Geospatial queries Licence PostgreSQL (permissive, MIT/BSD-like) GPL (Oracle) SSPL (restrictive) Popularity 2025 55.6% of developers 40.5% of developers 24.0% of developers
The table shows PostgreSQL ahead in every category that matters to a business: data integrity, AI readiness, scalability and licensing freedom. MySQL works well for simpler web projects, and MongoDB suits rapid prototyping with a changing data schema.
4. PostgreSQL in practice: who builds on it and why
The list of PostgreSQL users reads like a roll call of technology leaders. Over 48,000 companies worldwide run their systems on it, including Apple, Netflix, Instagram, Spotify, Uber, Reddit, Discord, Stripe and Coinbase. In the public sector it is used by organisations such as the U.S. State Department and NASA.
OpenAI is the most telling example. The company behind ChatGPT runs a single PostgreSQL cluster on Azure with nearly 50 read replicas, serving over 800 million users. It handles millions of queries per second, and OpenAI's engineers stress that architecture should follow analysis of the workload, not scaling panic or infrastructure fashion.
Migration from MongoDB to PostgreSQL is speeding up. Uber moved large parts of its data from MongoDB to PostgreSQL with JSONB. Notion runs its entire product on PostgreSQL. Infisical published a detailed account of its move from MongoDB to PostgreSQL and reported a 50% reduction in database costs afterwards.
According to market data, demand for PostgreSQL specialists has grown by roughly 73%, and salaries for PostgreSQL roles are on average 12% higher than for comparable MySQL positions. The signal is clear: companies invest in PostgreSQL because they see it as the future.
5. When PostgreSQL is the right call: business scenarios
Custom CRM and ERP systems
If your company needs a system built around its own processes, with complex relationships between customers, products, orders and finances, PostgreSQL is the natural choice. Full ACID compliance, advanced SQL queries and custom data types let the system grow with your business while keeping the data consistent.
E-commerce platforms and marketplaces
In online retail every transaction has to be reliable. PostgreSQL keeps cart operations, payments and stock updates consistent even with thousands of concurrent users. Add full-text product search and geospatial data for logistics, and you have a complete solution in one database.
Stripe, one of the world's largest payment processors, also runs on PostgreSQL. Where any inconsistency can mean real financial loss, full ACID transaction support is a necessity, not a luxury.
Systems with an AI component
Companies planning AI features such as intelligent search, recommendations or vector-based chatbots can store embeddings directly in PostgreSQL with pgvector. There is no separate vector database to maintain, and the whole architecture gets simpler.
Process automation and integrations
PostgreSQL works well with frameworks like Laravel, Django and Node.js. JSONB lets you store data from different integration sources (APIs, webhooks, files) flexibly, while keeping full transactional integrity and good reporting.
At our agency we build custom automation systems on a Laravel + Vue.js stack with PostgreSQL as the base. This combination gives you the flexibility of varied data storage (thanks to JSONB) together with full relational integrity and transaction safety, which is essential for systems that process financial, inventory or HR data.
6. How to decide: practical guidance
Don't choose a database by trend or by developer preference. Choose it by analysing what your business needs. These are the questions to ask:
How complex are the relationships in your data? With intricate connections (customers, orders, products, invoices), PostgreSQL or MySQL is the better fit. MongoDB suits flat, independent documents.
How critical is data consistency? If errors cost money (finance, inventory, contracts), PostgreSQL with full ACID is the safe choice.
Are you planning an AI component? If so, PostgreSQL with pgvector saves you extra infrastructure.
How many users do you serve? PostgreSQL has proven scalability at 800 million users (OpenAI). For the vast majority of businesses that is headroom for decades.
What is your budget? PostgreSQL is completely free with a permissive licence (MIT-like). MongoDB's advanced features may cost money, and MySQL is under Oracle's GPL licence.
In the vast majority of business scenarios, from small companies to global platforms, PostgreSQL is the safest and most future-proof choice. OpenAI, Instagram and Spotify have confirmed it at a scale that leaves little room for doubt.
Conclusion: PostgreSQL is a solid foundation for your system
Choosing a database is not only a technical decision. It is a strategic one that affects maintenance costs, scalability, data security and readiness for new technology. PostgreSQL gives the best balance of these, as both market data and the practice of leading technology companies show.
MySQL has its place in simpler web projects. MongoDB can work for rapid prototyping. But if you are building a system that has to run for years, serve a growing user base, work with new technologies and protect critical business data, PostgreSQL is the one choice that needs no compromises.
As a boutique IT agency specialising in custom CRM, ERP and automation systems, we recommend PostgreSQL to our clients as the default database. That is no coincidence. It comes from years of watching how different technologies behave in real production business environments. PostgreSQL combines what a modern system needs: reliability, scalability, AI readiness and complete freedom from vendor lock-in.
Need a system built around your business processes?
If you are planning a custom CRM, ERP or automation system, get in touch. Our senior developers will help you turn business goals into concrete IT solutions and pick the right technology, including the database, for your needs.
