PostgREST

PostgREST serves a fully RESTful API from any existing PostgreSQL database. It is a fast, declarative alternative to writing custom backend applications. In fact, PostgREST is a standalone web server that turns your PostgreSQL database directly into a RESTful API.

The Database as the API Foundation

When building applications, developers frequently write repetitive CRUD code. Using PostgREST is an alternative to manual CRUD programming. Because the server maps tables and views to URL paths, your application logic lives directly in the database. The structural constraints and permissions in the database determine the API endpoints and operations.

Instead of configuring a separate authentication layer in an application framework, you assign permissions natively using PostgreSQL roles. When a request comes in, PostgREST will switch into this role in the database to run queries. You can use your OS package manager to install PostgREST. Alternatively, you can run the application directly from pre-built binaries.

Focused Scope and Architecture

PostgREST has a focused scope. It works well with other tools like Nginx. This forces you to cleanly separate the data-centric CRUD operations from other concerns. Rather than building a monolithic application, you deploy a collection of sharp tools that each handle specific responsibilities efficiently. For instance, Nginx can be used as a reverse proxy to handle SSL termination, rate limiting, and request routing, while PostgREST is exclusively dedicated to transforming HTTP requests into SQL queries. This architectural pattern allows database administrators and backend engineers to build APIs from scratch with minimal custom programming outside of standard SQL statements.

Starting the Database Service

For new deployments or testing, you can begin by launching a PostgreSQL container. This ensures an isolated environment without conflicting with existing services. Run the following command to start the database service:

Creating the Schema and Tables

The underlying database configuration determines the API layout. Start by establishing a designated schema for the endpoints. Connect to the database and issue the schema creation command:

With the schema established, you can define tables that represent the resources. For a basic checklist API, create a table with a few initial records:

The server automatically identifies the api.todos table and creates a /todos endpoint for clients.

Configuring Access Roles

A production-ready database should restrict access. Instead of allowing external requests to use the highly privileged administration account, configure an anonymous role for unauthenticated web traffic:

This web_anon role specifically permits reading data from the defined schema without allowing login privileges. Next, create a dedicated role that the server uses to authenticate to the database:

Server Configuration and Execution

PostgREST relies on a configuration file to determine connection parameters. Create a configuration file containing the necessary database URI, the exposed schema, and the anonymous role:

Fetching the Data

Once the server is running, the RESTful API is immediately available for querying. Use a command-line HTTP client to test the exposed /todos endpoint:

The server responds with a JSON array reflecting the inserted table rows. For more comprehensive guides, consult the official documentation.