devenv.yaml

Key	Value
clean.enabled	Clean the environment when entering the shell. Defaults to `false`.
clean.keep	A list of environment variables to keep when cleaning the environment.
imports	A list of relative paths, absolute paths, or references to inputs to import `devenv.nix` and `devenv.yaml` files.
impure	Relax the hermeticity of the environment.
inputs	Defaults to `inputs.nixpkgs.url: github:cachix/devenv-nixpkgs/rolling`.
inputs.<name>	Identifier name used when passing the input in your `devenv.nix` function.
inputs.<name>.flake	Does the input contain `flake.nix` or `devenv.nix`. Defaults to `true`.
inputs.<name>.overlays	A list of overlays to include from the input.
inputs.<name>.url	URI specification of the input, see below for possible values.

nixpkgs.allowBroken	Allow packages marked as broken. Defaults to `false`.
nixpkgs.allowUnfree	Allow unfree packages. Defaults to `false`.
nixpkgs.cudaCapabilities	Select CUDA capabilities for nixpkgs. Defaults to `[]`
nixpkgs.cudaSupport	Enable CUDA support for nixpkgs. Defaults to `false`.
nixpkgs.permittedInsecurePackages	A list of insecure permitted packages. Defaults to `[]`
nixpkgs.permittedUnfreePackages	A list of unfree packages to allow by name. Defaults to `[]`

nixpkgs.per-platform.<system>.allowBroken	(per-platform) Allow packages marked as broken. Defaults to `false`.
nixpkgs.per-platform.<system>.allowUnfree	(per-platform) Allow unfree packages. Defaults to `false`.
nixpkgs.per-platform.<system>.cudaCapabilities	(per-platform) Select CUDA capabilities for nixpkgs. Defaults to `[]`
nixpkgs.per-platform.<system>.cudaSupport	(per-platform) Enable CUDA support for nixpkgs. Defaults to `false`.
nixpkgs.per-platform.<system>.permittedInsecurePackages	(per-platform) A list of insecure permitted packages. Defaults to `[]`
nixpkgs.per-platform.<system>.permittedUnfreePackages	(per-platform) A list of unfree packages to allow by name. Defaults to `[]`

secretspec.enable	Enable secretspec integration. Defaults to `false`.
secretspec.profile	Secretspec profile name to use.
secretspec.provider	Secretspec provider to use.

Added in 1.9

nixpkgs.permittedUnfreePackages

Added in 1.8

secretspec

Added in 1.7

nixpkgs

Added in 1.0

relative file support in imports: ./mymodule.nix
clean
impure
allowBroken

inputs.<name>.url

github:NixOS/nixpkgs/master
github:NixOS/nixpkgs?rev=238b18d7b2c8239f676358634bfb32693d3706f3
github:foo/bar?dir=subdir
git+ssh://[email protected]/NixOS/nix?ref=v1.2.3
git+https://git.somehost.tld/user/path?ref=branch&rev=fdc8ef970de2b4634e1b3dca296e1ed918459a9e
path:/path/to/repo
hg+https://...
tarball+https://example.com/foobar.tar.gz
sourcehut:~misterio/nix-colors/21c1a380a6915d890d408e9f22203436a35bb2de?host=hg.sr.ht
file+https://
file:///some/absolute/file.tar.gz

An extensive example

allowUnfree: true
allowBroken: true
clean:
  enabled: true
  keep:
    - EDITOR
inputs:
  nixpkgs:
    url: github:cachix/devenv-nixpkgs/rolling
  myproject:
    url: github:owner/myproject
    flake: false
  myproject2:
    url: github:owner/myproject
    overlays:
      - default
imports:
  - ./frontend
  - ./backend
  - ./mymodule.nix
  - /absolute/path/from/git/root
  - myproject
  - myproject/relative/path

Added in 1.10

local imports now merge devenv.yaml (remote inputs not yet supported)
absolute path support in imports: /absolute/path/from/git/root

Added in 1.0

relative file support in imports: ./mymodule.nix

Using permittedUnfreePackages

Instead of allowing all unfree packages with nixpkgs.allowUnfree: true, you can selectively permit specific unfree packages by name:

# Use the nixpkgs-scoped configuration
nixpkgs:
  permittedUnfreePackages:
    - terraform
    - vscode

# Or configure per-platform
nixpkgs:
  per-platform:
    x86_64-linux:
      permittedUnfreePackages:
        - some-package
    aarch64-darwin:
      permittedUnfreePackages:
        - some-package

What if a package is out of date?

Open nixpkgs repo and press t to search for your package.
Try to update/change the package using the nixpkgs contributing guide, optionally contacting the maintainer for help if you get stuck.
Make a PR and remember the branch name.
Add it to your devenv.yaml using the nixpkgs input in form of 'github:$GH_USERNAME/nixpkgs/master', edit devenv.yaml:

inputs:
  nixpkgs:
    url: 'github:$GH_USERNAME/nixpkgs/MYBRANCH'