Cloudant vs PostgreSQL

What Cloudant is

IBM Cloudant is a proprietary managed JSON document database built on Apache CouchDB, with a compatible HTTPS API and replication protocol. The Lite plan is free for evaluation and fixes capacity at 20 reads, 10 writes and five global queries per second with 1 GB storage. Standard begins at one provisioned capacity block—100 reads, 50 writes and five global queries per second—includes 20 GB and bills capacity plus excess storage hourly. Dedicated Hardware adds workload isolation, private networking and selected compliance and key-management options. A Cloudant service is not the same as self-hosting CouchDB.

What PostgreSQL is

PostgreSQL is the world's most advanced open-source relational database. Renowned for its reliability, feature robustness, and performance, it has become the standard choice for professional developers. Unlike many other SQL databases, Postgres handles complex data types, provides advanced indexing, and supports high-concurrency environments with ease. Its extensibility is its superpower; you can add features like geographic data support (PostGIS) or vector storage (pgvector) to make it suit any modern application needs.

What Cloudant is built to do

JSON document database

Stores schema-flexible documents, attachments and secondary indexes behind HTTPS APIs.

CouchDB-compatible replication

Supports replication patterns between Cloudant regions and compatible CouchDB systems.

Provisioned throughput

Scales read, write and global-query capacity in linked blocks through the dashboard or API.

IBM IAM and SDKs

Integrates IBM Cloud access controls and provides supported Java, Node.js, Python, Swift, Go and mobile clients.

What PostgreSQL is built to do

Full ACID Compliance

Ensures that your database transactions are processed reliably and safely.

JSONB Support

Store and query unstructured data with high performance alongside your SQL tables.

PostGIS

The world's best extension for handling geographic and spatial data.

Full-Text Search

Built-in advanced search capabilities that rival dedicated search engines.

Choose Cloudant if

• Offline or distributed applications that benefit from CouchDB-style replication
• JSON workloads dominated by key lookups and well-designed partitioned queries
• Teams able to test request-class capacity, 429 handling and multi-region conflicts

Skip Cloudant if

• The application depends on relational joins, broad ad-hoc SQL or multi-document ACID transactions
• Traffic is too unpredictable to provision and monitor request-class capacity
• A free Lite instance is being treated as a production SLA or scalable datastore

Choose PostgreSQL if

• Any project that needs a database with no licence fee — the PostgreSQL License grants use "without fee"
• Commercial products: the licence permits use, copy, modify and distribute for any purpose without a written agreement
• Teams that want long-term certainty; the project states there are no plans to change the licence

Skip PostgreSQL if

• You want a vendor with a support contract included — support is bought separately from third parties
• You need managed backups and failover out of the box; those come from hosted providers, not the project
• You are comparing total cost: the software is free, the operations are not

Cloudant: pros & cons

• Managed document service: IBM handles database servers, upgrades, patching and core high-availability infrastructure.
• CouchDB lineage: Compatible HTTP APIs and replication ease selected CouchDB application and migration patterns.
• Explicit capacity model: Read, write and global-query throughput are provisioned in documented blocks.
• Multi-region option: Application-managed replication can support active-active regional architectures.
• Lite is evaluation capacity: It cannot scale and blocks new writes above its storage limit.
• Capacity dimensions scale together: A workload dominated by one request class may pay for unused allowances in the others.
• Exceeding throughput returns 429: Applications need retry, backoff and load testing rather than assuming automatic unlimited scale.
• Cross-region is not automatic application resilience: Conflict behavior, traffic routing, monitoring and recovery remain design responsibilities.

PostgreSQL: pros & cons

• Rock-Solid Reliability: Known for data integrity and full ACID compliance.
• Extensible Architecture: Add new data types and functions via a massive plugin ecosystem.
• JSONB Support: Combines the power of relational data with NoSQL-like flexibility.
• Open Source: Free to use forever with no licensing fees for any scale.
• Learning Curve: Mastering performance tuning and advanced features takes time.
• Operational Overhead: Managing it yourself requires significant DBA knowledge.
• Memory Usage: Each connection consumes a dedicated process, requiring careful pool management.