PostgreSQL vs MariaDB

Quick verdict

PostgreSQL is an open source object-relational database developed by the PostgreSQL Global Development Group under the PostgreSQL Licence, which the project describes as a liberal licence similar to BSD or MIT. The current release series is PostgreSQL 18 (18.6 at the time of checking), with 19 in beta.

MariaDB Server began as a fork of MySQL by MySQL's original developers. It is licensed under GPLv2, and the non-profit MariaDB Foundation states the server will stay free and open source; MariaDB plc sells MariaDB Enterprise Platform separately. MariaDB releases a yearly long-term support series with quarterly rolling releases: 12.3 is the current LTS and 13.0 the newest rolling release.

Side by side

Key differences

Licences and governance

Both are free to use. The PostgreSQL Licence is permissive: you can modify and redistribute PostgreSQL, including inside proprietary products, with only the copyright notice to keep. MariaDB Server is GPLv2, a copyleft licence whose obligations apply when you distribute the software; running it as a server for your own application does not trigger them. PostgreSQL is run by a community development group with no single owning company. MariaDB Server is stewarded by the MariaDB Foundation, with MariaDB plc selling enterprise products and support.

JSON: jsonb against JSON as text

PostgreSQL stores jsonb in a decomposed binary format that its documentation recommends for most applications; it supports containment and key-existence operators and GIN indexes. MariaDB documents its JSON type as an alias for LONGTEXT with an automatic JSON_VALID() check, so documents are stored as text and queried with functions such as JSON_VALUE and JSON_EXTRACT; JSON strings compare as normal strings. To index a JSON field in MariaDB you typically index a generated column.

-- PostgreSQL
CREATE INDEX idx_doc ON customers USING GIN (doc);
SELECT doc->>'name' AS name FROM customers WHERE doc @> '{"tier": "gold"}';

-- MariaDB
SELECT JSON_VALUE(doc, '$.name') AS name FROM customers
WHERE JSON_VALUE(doc, '$.tier') = 'gold';

Extensions against storage engines

The two engines extend in different directions. PostgreSQL loads extensions into a database with CREATE EXTENSION, adding data types, functions, index types and languages; widely used examples include PostGIS for geospatial data and pgvector for vector similarity search. Managed services each publish which extensions they allow.

MariaDB extends through plugins and pluggable storage engines chosen per table: InnoDB is the default, alongside MariaDB engines such as Aria, ColumnStore (columnar analytics), MyRocks, Spider (sharding), S3 and CONNECT. MariaDB also has a built-in VECTOR type and vector indexes, introduced in 11.7 and generally available from the 11.8 LTS series, so vector search does not need an add-on.

Replication and high availability

PostgreSQL ships streaming replication, which copies the whole server synchronously or asynchronously to hot standbys, and logical replication, which publishes changes per table. Its documentation states that it does not offer synchronous multi-primary replication natively, so writes go to one primary and failover is handled by external tooling or a managed service.

MariaDB offers binary log replication with its own GTID format (not compatible with MySQL's), and integrates MariaDB Galera Cluster, which its documentation describes as a virtually synchronous multi-primary cluster where every node accepts reads and writes. Galera is available on Linux only and supports the InnoDB storage engine (with experimental support for others).

SQL dialect: RETURNING, sequences, upserts and aggregation

Both support sequences and RETURNING, with different syntax and coverage. PostgreSQL supports RETURNING on INSERT, UPDATE, DELETE and MERGE. MariaDB supports it on INSERT, DELETE and REPLACE, and on single-table UPDATE only from the 13.0 rolling release, so not in the 12.3 LTS.

-- PostgreSQL
CREATE TABLE orders (id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY, total numeric(10,2));
INSERT INTO orders (total) VALUES (19.99) RETURNING id;
CREATE SEQUENCE invoice_seq START WITH 1000;
SELECT nextval('invoice_seq');

-- MariaDB
CREATE TABLE orders (id INT AUTO_INCREMENT PRIMARY KEY, total DECIMAL(10,2));
INSERT INTO orders (total) VALUES (19.99) RETURNING id;
CREATE SEQUENCE invoice_seq START WITH 1000;
SELECT NEXTVAL(invoice_seq);

Upserts and string aggregation also differ. PostgreSQL has INSERT ... ON CONFLICT and MERGE; MariaDB uses MySQL-style ON DUPLICATE KEY UPDATE. Both use LIMIT for row limiting.

-- PostgreSQL
INSERT INTO stock (sku, qty) VALUES ('A1', 5)
ON CONFLICT (sku) DO UPDATE SET qty = EXCLUDED.qty;
SELECT string_agg(name, ', ' ORDER BY name) FROM staff;

-- MariaDB
INSERT INTO stock (sku, qty) VALUES ('A1', 5)
ON DUPLICATE KEY UPDATE qty = VALUES(qty);
SELECT GROUP_CONCAT(name ORDER BY name SEPARATOR ', ') FROM staff;

For concurrency, both use multiversion concurrency control. PostgreSQL defaults to read committed; MariaDB's InnoDB defaults to repeatable read, and MariaDB 12.3 turned innodb_snapshot_isolation on by default, which the Foundation advises checking before upgrading.

Managed services and tools

PostgreSQL is offered by Amazon RDS and Aurora, Google Cloud SQL, Azure Database for PostgreSQL and many specialist providers. MariaDB is available on Amazon RDS, but not on Google Cloud SQL, and Microsoft retired Azure Database for MariaDB on 19 September 2025. If you need a managed database on Google Cloud or Azure, that points to PostgreSQL (or MySQL, see MariaDB vs MySQL).

For GUI tools, pgAdmin is the PostgreSQL project's own GUI, HeidiSQL supports MariaDB, MySQL and PostgreSQL, and DBeaver and DataGrip cover both. See PostgreSQL GUI tools and MySQL GUI tools for more.

Pricing and licensing

PostgreSQL. Free under the PostgreSQL Licence. Commercial support and managed hosting are sold by third parties and cloud providers at their own rates.

MariaDB. MariaDB Server is free under GPLv2. MariaDB Enterprise Platform is a commercial product; prices were not published on the product page checked, which directs buyers to sales. Amazon RDS for MariaDB is billed at AWS rates.

Pricing checked on the vendors' official pages on 7 October 2026. Prices change; confirm before buying.

Where each one leads

Limitations

When to choose each

When neither is right

• You need an embedded, serverless database inside an app: see SQLite vs PostgreSQL.
• You need MySQL-specific features such as Group Replication or binary JSON with MySQL operators: see MariaDB vs MySQL and MySQL vs PostgreSQL.
• You need a commercial engine with vendor support and enterprise options: see PostgreSQL vs Oracle and SQL Server vs PostgreSQL.

Final recommendation

Frequently asked questions

Sources

• PostgreSQL Licence
• PostgreSQL 18 documentation: JSON types
• PostgreSQL 18 documentation: Comparison of replication solutions
• MariaDB Foundation: About MariaDB Server
• MariaDB Foundation: All MariaDB Server releases
• MariaDB documentation: JSON data type
• MariaDB documentation: UPDATE (RETURNING from 13.0)
• MariaDB documentation: Vector overview
• MariaDB documentation: What is MariaDB Galera Cluster?
• MariaDB documentation: MariaDB versus MySQL compatibility
• pgvector extension (GitHub)
• Microsoft Lifecycle: Azure Database for MariaDB
• Amazon RDS
• Google Cloud SQL documentation

Checked October 2026.

How we research comparisons: our editorial method.