Deploy to Deno Deploy

With this guide, you can learn how to build and deploy a REST API to Deno Deploy. The application uses Prisma ORM to manage tasks in a Prisma Postgres database.

This guide covers Deno CLI, Deno Deploy, Prisma Client with the Postgres adapter, and Prisma Postgres.

Prerequisites

A free Prisma Data Platform account
A free Deno Deploy account
Deno v2.0 or later installed
(Recommended) Deno extension for VS Code

1. Set up your application

Create a new directory and initialize your Prisma project:

mkdir prisma-deno-deploy
cd prisma-deno-deploy
deno run -A npm:prisma@latest init --db

Enter a name for your project and choose a database region.

This command:

Connects to the Prisma Data Platform (opens browser for authentication)
Creates a prisma/schema.prisma file for your database models
Creates a .env file with your DATABASE_URL
Creates a prisma.config.ts configuration file

2. Configure Deno

Create a deno.json file with the following configuration:

deno.json

{
  "nodeModulesDir": "auto",
  "compilerOptions": {
    "lib": ["deno.window"],
    "types": ["node"]
  },
  "imports": {
    "@prisma/adapter-pg": "npm:@prisma/adapter-pg@^7.0.0",
    "@prisma/client": "npm:@prisma/client@^7.0.0",
    "prisma": "npm:prisma@^7.0.0"
  },
  "tasks": {
    "dev": "deno run -A --env=.env --watch index.ts",
    "db:generate": "deno run -A --env=.env npm:prisma generate",
    "db:push": "deno run -A --env=.env npm:prisma db push",
    "db:migrate": "deno run -A --env=.env npm:prisma migrate dev",
    "db:studio": "deno run -A --env=.env npm:prisma studio"
  }
}

The nodeModulesDir: "auto" setting is required for Prisma to work correctly with Deno. The compilerOptions ensure TypeScript understands Deno globals and npm packages. The import map allows you to use clean import paths like @prisma/adapter-pg instead of npm:@prisma/adapter-pg.

Install the dependencies:

deno install
deno install --allow-scripts

3. Define your data model

Edit prisma/schema.prisma to add the Deno runtime and a Task model:

prisma/schema.prisma

generator client {
  provider = "prisma-client"
  output   = "../generated/prisma"
  runtime  = "deno"
}

datasource db {
  provider = "postgresql"
}

model Task {
  id          Int      @id @default(autoincrement())
  title       String
  description String?
  completed   Boolean  @default(false)
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt
}

4. Push the schema to your database

Apply the schema to your database and generate Prisma Client:

deno task db:push

This command:

Creates the Task table in your Prisma Postgres database
Generates the Prisma Client with full type safety

If you see TypeScript errors in your IDE after generating, restart the Deno language server (Cmd/Ctrl + Shift + P → "Deno: Restart Language Server") to refresh the types.

5. Create your application

Create index.ts with a REST API for managing tasks:

index.ts

import { PrismaPg } from "@prisma/adapter-pg";
import { PrismaClient } from "./generated/prisma/client.ts";

// Initialize Prisma Client with the Postgres adapter
const connectionString = Deno.env.get("DATABASE_URL")!;
const adapter = new PrismaPg({ connectionString });
const prisma = new PrismaClient({ adapter });

// Helper to create JSON responses
function json(data: unknown, status = 200): Response {
  return new Response(JSON.stringify(data, null, 2), {
    status,
    headers: { "Content-Type": "application/json" },
  });
}

// Request handler
async function handler(request: Request): Promise<Response> {
  const url = new URL(request.url);
  const path = url.pathname;
  const method = request.method;

  try {
    // GET /tasks - List all tasks
    if (method === "GET" && path === "/tasks") {
      const tasks = await prisma.task.findMany({
        orderBy: { createdAt: "desc" },
      });
      return json(tasks);
    }

    // POST /tasks - Create a new task
    if (method === "POST" && path === "/tasks") {
      const body = await request.json();
      const task = await prisma.task.create({
        data: {
          title: body.title,
          description: body.description,
        },
      });
      return json(task, 201);
    }

    // GET /tasks/:id - Get a specific task
    const taskMatch = path.match(/^\/tasks\/(\d+)$/);
    if (taskMatch) {
      const id = parseInt(taskMatch[1]);

      if (method === "GET") {
        const task = await prisma.task.findUnique({ where: { id } });
        if (!task) return json({ error: "Task not found" }, 404);
        return json(task);
      }

      // PATCH /tasks/:id - Update a task
      if (method === "PATCH") {
        const body = await request.json();
        const task = await prisma.task.update({
          where: { id },
          data: body,
        });
        return json(task);
      }

      // DELETE /tasks/:id - Delete a task
      if (method === "DELETE") {
        await prisma.task.delete({ where: { id } });
        return json({ message: "Task deleted" });
      }
    }

    // GET / - API info
    if (method === "GET" && path === "/") {
      return json({
        name: "Prisma + Deno Task API",
        version: "1.0.0",
        endpoints: {
          "GET /tasks": "List all tasks",
          "POST /tasks": "Create a task",
          "GET /tasks/:id": "Get a task",
          "PATCH /tasks/:id": "Update a task",
          "DELETE /tasks/:id": "Delete a task",
        },
      });
    }

    return json({ error: "Not found" }, 404);
  } catch (error) {
    console.error(error);
    return json({ error: "Internal server error" }, 500);
  }
}

// Start the server
Deno.serve({ port: 8000 }, handler);

This creates a full CRUD API with the following endpoints:

Method	Endpoint	Description
GET	`/`	API info
GET	`/tasks`	List all tasks
POST	`/tasks`	Create a new task
GET	`/tasks/:id`	Get a specific task
PATCH	`/tasks/:id`	Update a task
DELETE	`/tasks/:id`	Delete a task

6. Test your application locally

Start the development server:

deno task dev

Test the API with curl:

# Get API info
curl http://localhost:8000/

# Create a task
curl -X POST http://localhost:8000/tasks \
  -H "Content-Type: application/json" \
  -d '{"title": "Learn Prisma", "description": "Complete the Deno guide"}'

# List all tasks
curl http://localhost:8000/tasks

# Update a task (mark as completed)
curl -X PATCH http://localhost:8000/tasks/1 \
  -H "Content-Type: application/json" \
  -d '{"completed": true}'

# Delete a task
curl -X DELETE http://localhost:8000/tasks/1

You should see JSON responses for each request. The task ID will increment with each new task created.

7. Create a GitHub repository

You need a GitHub repository to deploy to Deno Deploy.

Create a .gitignore file:

.gitignore

.env
node_modules/
generated/
deno.lock

Initialize and push your repository:

git init -b main
git remote add origin https://github.com/<username>/prisma-deno-deploy
git add .
git commit -m "Initial commit"
git push -u origin main

8. Deploy to Deno Deploy

Go to https://dash.deno.com/
Click New Project and select your GitHub repository
Configure the deployment:
- Framework preset: No Preset
- Install command: deno install
- Build command: deno run -A npm:prisma generate
- Entrypoint: index.ts
Click Create & Deploy

The first deployment will fail because you need to add the database connection string.

Add environment variables

Go to your project's Settings > Environment Variables
Add a new variable:
- Key: DATABASE_URL
- Value: Your Prisma Postgres connection string (copy from your .env file)
Click Save

Trigger a new deployment by clicking Redeploy or pushing a new commit.

9. Test your deployed API

Once deployed, test your API at your Deno Deploy URL:

# Replace with your actual Deno Deploy URL
curl https://your-project.deno.dev/

# Create a task
curl -X POST https://your-project.deno.dev/tasks \
  -H "Content-Type: application/json" \
  -d '{"title": "Deploy to production"}'

# List tasks
curl https://your-project.deno.dev/tasks

Summary

You successfully deployed a REST API to Deno Deploy using:

Deno as the runtime with native TypeScript support
Prisma ORM with the Postgres adapter for type-safe database access
Prisma Postgres as the managed database

Your project structure should look like this:

prisma-deno-deploy/
├── deno.json
├── index.ts
├── prisma/
│   └── schema.prisma
├── prisma.config.ts
├── generated/
│   └── prisma/
│       └── ...
└── .env

Next steps

Add authentication using Deno KV for sessions
Add request validation with Zod
Explore Prisma Client extensions for custom functionality
Set up Prisma Migrate for schema versioning in production

Deploy to Deno Deploy

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