Skip to main content


Build Status Discord server Manual Documentation License

A lightweight PostgreSQL driver for Deno focused on user experience

deno-postgres is being developed based on excellent work of node-postgres and pq.


// deno run --allow-net --allow-read --unstable mod.ts
import { Client } from "";

const client = new Client({
  user: "user",
  database: "test",
  hostname: "localhost",
  port: 5432,
await client.connect();

  const result = await client.queryArray("SELECT ID, NAME FROM PEOPLE");
  console.log(result.rows); // [[1, 'Carlos'], [2, 'John'], ...]

  const result = await client.queryArray
  console.log(result.rows); // [[1, 'Carlos']]

  const result = await client.queryObject("SELECT ID, NAME FROM PEOPLE");
  console.log(result.rows); // [{id: 1, name: 'Carlos'}, {id: 2, name: 'Johnru'}, ...]

  const result = await client.queryObject
  console.log(result.rows); // [{id: 1, name: 'Carlos'}]

await client.end();

For more examples visit the documentation available at

Why do I need unstable to connect using TLS?

Sadly, establishing a TLS connection in the way Postgres requires it isn’t possible without the Deno.startTls API, which is currently marked as unstable.

At least that was the situation before Deno 1.16, which stabilized the required API making it possible to use the library without requiring --unstable. Users are urged to upgrade to Deno 1.16 or above to enjoy this feature


The documentation is available on the deno-postgres website

Join me on Discord as well! It’s a good place to discuss bugs and features before opening issues



  • You must have docker and docker-compose installed in your machine

  • You don’t need deno installed in your machine to run the tests, since it will be installed in the Docker container when you build it. However you will need it in order to run the linter and formatter locally

  • You don’t need to install Postgres locally in your machine in order to test the library, it will run as a service in the Docker container when you build it

Running the tests

The tests are found under the ./tests folder, and they are based on query result assertions

In order to run the tests run the following commands

  1. docker-compose build tests
  2. docker-compose run tests

The build step will check linting and formatting as well and report it to the command line

It is recommended that you don’t rely on any previously initialized data for your tests, instead of that create all the data you need at the moment of running the tests

For example, the following test will create a temporal table that will disappear once the test has been completed

Deno.test("INSERT works correctly", async () => {
  await client.queryArray(
  await client.queryArray(
  const result = await client.queryObject<{ x: number }>({
    text: `SELECT X FROM MY_TEST`,
    fields: ["x"],
  assertEquals(result.rows[0].x, 1);

Setting up an advanced development environment

More advanced features such as the Deno inspector, test and permission filtering, database inspection and test code lens can be achieved by setting up a local testing environment, as shown in the following steps:

  1. Start the development databases using the Docker service with the command
    docker-compose up postgres_classic postgres_scram
    Though using the detach (-d) option is recommended, this will make the databases run in the background unless you use docker itself to stop them. You can find more info about this here

  2. Set the DENO_POSTGRES_DEVELOPMENT environmental variable to true, either by prepending it before the test command (on Linux) or setting it globally for all environments

    The DENO_POSTGRES_DEVELOPMENT variable will tell the testing pipeline to use the local testing settings specified in tests/config.json, instead of the CI settings

  3. Run the tests manually by using the command
    deno test --unstable -A

Deno compatibility

Due to breaking changes introduced in the unstable APIs deno-postgres uses, there has been some fragmentation regarding what versions of Deno can be used alongside the library

This situation will become more stable as std and deno-postgres approach 1.0

Deno version Min driver version Max driver version
1.8.x 0.5.0 0.10.0
1.9.0 0.11.0 0.11.1
1.9.1 and up 0.11.2 0.11.3
1.11.0 and up 0.12.0 0.12.0
1.14.0 and up 0.13.0 0.13.0
1.15.0 0.13.0
1.16.0 0.14.0

Contributing guidelines

When contributing to repository make sure to:

  1. All features and fixes must have an open issue in order to be discussed
  2. All public interfaces must be typed and have a corresponding JS block explaining their usage
  3. All code must pass the format and lint checks enforced by deno fmt and deno lint --config=deno.json respectively. The build will not pass the tests if these conditions are not met. Ignore rules will be accepted in the code base when their respective justification is given in a comment
  4. All features and fixes must have a corresponding test added in order to be accepted


There are substantial parts of this library based on other libraries. They have preserved their individual licenses and copyrights.

Everything is licensed under the MIT License.

All additional work is copyright 2018 - 2021 — Bartłomiej Iwańczuk and Steven Guerrero — All rights reserved.