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Latest from the blogJul 28, 2026devenv 2.2: attach to running processes and persistent out-of-tree environmentsRead post →

Your whole development environment, declared.

Define packages, languages, services, tasks, secrets, and tooling once. Give every developer—and CI—the same fast, reproducible environment.

Generate with AI →

Rust + Postgres

Python ML

Node + Redis

Go + MySQL

Rails + React

Ready to compose

Ingredient streamsDrag anything into the file. Send configured items back to remove them.

devenv.nix

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{ pkgs, ... }: {  languages = {    # devenv.sh/languages/rust/    rust = {      enable = true;      channel = "stable";    };  };   services = {    # devenv.sh/services/postgres/    postgres = {      enable = true;      initialDatabases = [{ name = "app"; }];    };     # devenv.sh/services/redis/    redis.enable = true;  };   # devenv.sh/tasks/  tasks."app:test".exec = "cargo test";   # devenv.sh/integrations/secretspec/  processes.api.exec =    "secretspec run -- cargo run";   packages = [    # devenv.sh/packages/    pkgs.docker  ];}

Ydevenv.yaml

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devenv.nix✦

Composing with AI

Teaching your stack to speak Nix.

Reading your stack

Languages · Services · Tools

ANAnsible

CLClojure

C+C++

CRCrystal

CUCUE

DADart

DEDeno

NE.NET

ELElixir

ELElm

ERErlang

FOFortran

GNGNU Awk

GLGleam

GOGo

HAHare

HAHaskell

HEHelm

IDIdris

JAJava

JAJavaScript

JSJsonnet

JUJulia

KOKotlin

LELean 4

LOLobster

LULua

NINim

NINix

OCOCaml

ODOdin

OPOpenTofu

PAPascal

PEPerl

PHPHP

PKPkl

PUPureScript

PYPython

RARacket

RARaku

RORobot Framework

RURuby

RURust

SCScala

SHShell

SOSolidity

STStandard ML

SWSwift

TETerraform

TETeX Live

TYTypeScript

TYTypst

UNUnison

VAVala

ZIZig

ANAnsible

CLClojure

C+C++

CRCrystal

CUCUE

DADart

DEDeno

NE.NET

ELElixir

ELElm

ERErlang

FOFortran

GNGNU Awk

GLGleam

GOGo

HAHare

HAHaskell

HEHelm

IDIdris

JAJava

JAJavaScript

JSJsonnet

JUJulia

KOKotlin

LELean 4

LOLobster

LULua

NINim

NINix

OCOCaml

ODOdin

OPOpenTofu

PAPascal

PEPerl

PHPHP

PKPkl

PUPureScript

PYPython

RARacket

RARaku

RORobot Framework

RURuby

RURust

SCScala

SHShell

SOSolidity

STStandard ML

SWSwift

TETerraform

TETeX Live

TYTypeScript

TYTypst

UNUnison

VAVala

ZIZig

ADAdminer

BLBlackfire

CACaddy

CACassandra

CLClickHouse

COCockroachDB

COCouchDB

DYDynamoDB Local

ELElasticMQ

ELElasticsearch

GAGarage

HThttpbin

INInfluxDB

KAKafka

KEKeycloak

MAMailHog

MAMailpit

MEMeilisearch

MEMemcached

MIMinIO

MOMongoDB

MOMosquitto

MYMySQL

NANATS

NGnginx

NINixseparatedebuginfod

OPOpenSearch

OPOpenTelemetry Collector

POPostgreSQL

PRPrometheus

RARabbitMQ

RERedis

RURustFS

SQsqld

TATailscale Funnel

TETemporal

TITideways

TRTraffic Server

TYTypesense

VAVarnish

VAVault

WIWireMock

ADAdminer

BLBlackfire

CACaddy

CACassandra

CLClickHouse

COCockroachDB

COCouchDB

DYDynamoDB Local

ELElasticMQ

ELElasticsearch

GAGarage

HThttpbin

INInfluxDB

KAKafka

KEKeycloak

MAMailHog

MAMailpit

MEMeilisearch

MEMemcached

MIMinIO

MOMongoDB

MOMosquitto

MYMySQL

NANATS

NGnginx

NINixseparatedebuginfod

OPOpenSearch

OPOpenTelemetry Collector

POPostgreSQL

PRPrometheus

RARabbitMQ

RERedis

RURustFS

SQsqld

TATailscale Funnel

TETemporal

TITideways

TRTraffic Server

TYTypesense

VAVarnish

VAVault

WIWireMock

+Docker

+Git

+curl

{}jq

rgripgrep

+cargo-watch

AWSAWS CLI

+Terraform CLI

+Node.js 22

$✓ShellCheck

$_just

✓Test task

›_App process

◇SecretSpec

✓Pre-commit

+Docker

+Git

+curl

{}jq

rgripgrep

+cargo-watch

AWSAWS CLI

+Terraform CLI

+Node.js 22

$✓ShellCheck

$_just

✓Test task

›_App process

◇SecretSpec

✓Pre-commit

Three steps. Done.

From zero to a reproducible environment your whole team can use.

Install

Once Nix is installed. Works on Linux, macOS, and WSL.

$ nix profile install nixpkgs#devenv

Initialize & describe

Scaffold the project, then edit devenv.nix or generate it from a prompt above.

$ devenv init
$EDITOR devenv.nix

Activate

Everything available, in under 100ms after the first build.

$ devenv shell
(devenv) $ cargo run

Your whole stack, declared together

Languages, services, processes, tasks, and secrets. Everything is declarative.

Languages

Python, Rust, Go, Node, Ruby, PHP, Java, Elixir, and more, with version pinning and LSP servers.

Services

42 preconfigured services, including PostgreSQL, Redis, MySQL, RabbitMQ, MinIO, Caddy, and Elasticsearch.

services.postgres.enable = true;
services.redis.enable = true;

Processes

Declarative process management with logs, restarts, and dependencies. Just devenv up.

Tasks & git hooks

Define dependencies, run in parallel, hook into your shell or commits. Linters, formatters, codegen.

tasks."app:build" = {
  exec = "yarn build";
  before = [ "devenv:enterShell" ];
};

SecretSpec

Declarative secrets from Keychain, 1Password, LastPass, or dotenv. Keep values out of config and committed .env files.

processes.api.exec =
  "secretspec run -- npm start";

Containers

Build OCI containers from your dev environment. Same packages, same versions, same behavior.

Tests

Run integration tests with all processes active. devenv test and done.

Basics

Packages, variables, files, and scripts in native bash, zsh, fish, or nushell. Auto-activate on cd and apply updates at the next prompt.

Ad-hoc shells, zero config

Spin up a temporary environment without writing a devenv.nix. Great for experiments, scripts, and CI matrices.

$ devenv -O languages.python.enable:bool true \
       -O languages.python.version:string "3.12" \
       shell

Search packages & options

Search 100,000+ packages and every devenv option from the CLI, using the exact Nixpkgs version pinned by your project.

$ devenv search postgres
pkgs.postgresql_17
services.postgres.enable

Evaluation caching

Warm shells in milliseconds.

Auto-invalidated evaluation caching skips unchanged work. No daemons. No manual cache management. How it works.

Cached shell startup

<100ms

Cold

4832 ms

Warm

47 ms

Same config. ~100× faster on every subsequent shell.

Composability

Many environments. One shell.

Import config across folders and repositories. First-class monorepo support.

frontend/devenv.nix

languages.javascript.enable = true;

backend/devenv.nix

languages.rust.enable = true;
services.postgres.enable = true;

github:myorg/shared

services.redis.enable = true;

→

Unified environment

$ devenv shell

noderustpostgresredis

Profiles

One project. Every workflow.

Switch between frontend, backend, testing, and full-stack environments without duplicating configuration. Layer profiles manually or activate them by hostname and user.

$ devenv –profile backend shell

postgresredisAPI tools

$ devenv –profile fullstack up

backendfrontenddev server

hostname.ci-runner + user.alice

automaticdeterministic priority

devenv.nix

profiles = {
  backend.module = {
    services.postgres.enable = true;
    services.redis.enable = true;
  };

  frontend.module = {
    languages.javascript.enable = true;
    processes.dev.exec = "npm run dev";
  };

  fullstack.extends = [ "backend" "frontend" ];
};

Native process manager

One `devenv up`. Whole stack alive.

Built-in process supervision: dependencies, ready probes, restart policies, socket activation, automatic port allocation. Or swap in process-compose, overmind, mprocs.

postgresrunning

port :5432 · uptime 3m 12s

ready probe: pg_isready

redisrunning

port :6379 · uptime 3m 12s

restart: on-failure

migratecompleted

one-shot · exit 0

after: postgres

apirunning

port :8080 · uptime 3m 09s

after: postgres, redis, migrate

socket activation · zero-downtime restarts

Declared once in devenv.nix. Started, ordered, restarted, and stopped by the native supervisor.

SecretSpec

Declare a secret. Swap the source.

The same declaration reads from Keychain, 1Password, dotenv, or env. Load secrets at runtime without committing their values.

Keychain

1Password

LastPass

.env

env

secretspec.toml

[project]
name = "my-app"

[profiles.default]
DATABASE_URL = { required = true }
STRIPE_SECRET_KEY = { required = true }

🔐Source: macOS Keychain

↓

📄secretspec.toml declares DATABASE_URL

↓

🐚$ secretspec run -- npm start, exposed only to the app

Packaging

From dev shell to deployable artifact.

Same languages, same versions, same packages. Define outputs and ship a Nix derivation.

1 · Declare

devenv.nix

languages.rust.enable = true;
outputs.app =
  config.languages.rust.import ./. {};

→

2 · Build

devenv build

$ devenv build outputs.app
• Built /nix/store/...-app
in 12.4s

→

3 · Ship

Nix store · binary cache · CI

$ nix copy --to ssh://deploy \
  /nix/store/...-app

Built in the open

Active community, frequent releases, and a growing ecosystem of services and languages.

GitHubStar & contributeRead the source, file an issue, send a PR. MIT licensed.DiscordChat with the teamGet help, share setups, follow what’s coming next.BlogWhat’s newRelease notes, design deep-dives, and case studies.ExamplesReady-made setupsCopy a working devenv.nix for your stack.

Start building.

Set up your first environment in minutes, or generate one from the hero above.

Get Started View on GitHub

Last updated Oct 08, 2026