Building a REST API with Database Integration
By Fouad A.
14 April . 2026
Walk through building a complete REST API with PostgreSQL, authentication middleware, and auto-generated documentation - all from a single Syntera conversation.
Getting Started
Building a REST API from scratch involves a lot of boilerplate - routes, controllers, models, middleware, validation. Syntera handles all of it. Describe the API you need and it generates a production-ready backend.
Describe the resources and relationships
Tell Syntera what data your API manages, how entities relate, and what operations each endpoint supports. Start building
"Build a REST API for a project management tool with users, projects, and tasks. Include auth, pagination, and PostgreSQL."
API Planning
Syntera's Planner generates a structured API design before writing any code. The plan typically covers:
- • Resource endpoints (CRUD for each entity)
- • Database schema with relationships and indexes
- • Authentication and authorization middleware
- • Input validation schemas
- • Error handling patterns
Generated Plan: 1. Set up Next.js API routes structure 2. Create PostgreSQL schema (users, projects, tasks) 3. Implement auth middleware with JWT 4. Build CRUD endpoints for each resource 5. Add input validation with Zod schemas 6. Add pagination and filtering 7. Write API tests
Database Schema
Syntera generates the database schema directly in PostgreSQL, including tables, foreign keys, indexes, and seed data.
-- Auto-generated schema CREATE TABLE users ( id UUID PRIMARY KEY DEFAULT gen_random_uuid(), email VARCHAR(255) UNIQUE NOT NULL, password_hash VARCHAR(255) NOT NULL, name VARCHAR(255), created_at TIMESTAMP DEFAULT NOW() ); CREATE TABLE projects ( id UUID PRIMARY KEY DEFAULT gen_random_uuid(), name VARCHAR(255) NOT NULL, owner_id UUID REFERENCES users(id), created_at TIMESTAMP DEFAULT NOW() ); CREATE TABLE tasks ( id UUID PRIMARY KEY DEFAULT gen_random_uuid(), title VARCHAR(255) NOT NULL, status VARCHAR(50) DEFAULT 'pending', project_id UUID REFERENCES projects(id), assignee_id UUID REFERENCES users(id) );
The sandbox includes a running PostgreSQL instance, so Syntera can test queries and verify the schema in real time.
Route Implementation
Each route handler follows a consistent pattern with validation, auth checks, and error handling:
// app/api/projects/route.ts (auto-generated)
import { NextRequest, NextResponse } from 'next/server';
import { z } from 'zod';
import { requireAuth } from '@/lib/auth';
import { db } from '@/lib/database';
const createProjectSchema = z.object({
name: z.string().min(1).max(255),
description: z.string().optional(),
});
export async function POST(req: NextRequest) {
const user = await requireAuth(req);
const body = createProjectSchema.parse(await req.json());
const project = await db.query(
'INSERT INTO projects (name, owner_id) VALUES ($1, $2) RETURNING *',
[body.name, user.id]
);
return NextResponse.json(project.rows[0], { status: 201 });
}Syntera generates consistent patterns across all endpoints - validation first, then auth, then business logic, then response. This makes the generated code predictable and easy to extend.
Testing the API
Syntera runs the dev server in the sandbox so you can test endpoints immediately. It also generates test files for automated verification.
# Start the dev server in the sandbox
yarn dev
# Test an endpoint
curl -X POST http://localhost:3000/api/projects \
-H 'Authorization: Bearer <token>' \
-H 'Content-Type: application/json' \
-d '{"name": "My Project"}'Deployment Ready
The generated API is structured for easy deployment. Syntera includes:
- • Environment variable templates for production
- • Database migration scripts
- • Health check endpoints
- • CORS configuration
- • Rate limiting middleware
Conclusion
From a one-sentence description to a fully tested REST API with PostgreSQL, auth, and validation - Syntera generates production-quality backend code that follows established patterns. The sandbox lets you verify everything works before it reaches your repository.
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