{
  description = "Backend development flake";
  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
  outputs = {nixpkgs, ... }: let
    forAllSystems = nixpkgs.lib.genAttrs [
      "aarch64-linux"
      "i686-linux"
      "x86_64-linux"
      "aarch64-darwin"
      "x86_64-darwin"
    ];
  in {
    devShells = forAllSystems (system: let
      pkgs = import nixpkgs {
        inherit system;
        config = {
          android_sdk.accept_license = true;
          allowUnfree = true;
        };
      };
    in {
      default = pkgs.mkShell {
        packages = with pkgs; [
          (python312.withPackages (
            ppkgs:
              with python312Packages; [
                pip # python package manager
                fastapi # web framework
                pandas # data manipulation
                pydantic # data validation
                uvicorn # ASGI server
                sqlalchemy # ORM
                python-multipart # fastapi multipart form data
              ]
          ))
          fastapi-cli
          sqlitestudio
        ];
      };
    });
    # app for backing up the data
    apps = forAllSystems (system: let
      pkgs = import nixpkgs {
        inherit system;
        config = {
          android_sdk.accept_license = true;
          allowUnfree = true;
        };
      };
    in {
      default = pkgs.fastapi-cli;
      backup-db = pkgs.writeShellApplication {
        name = "backup-db";
        runtimeInputs = [ pkgs.zip ];
        text = ''
          # date
          DATE=$(date +%Y-%m-%d)
          # backup directory
          BACKUP_DIR=~/aifred-backup/
          # create backup directory if it doesn't exist
          mkdir -p $BACKUP_DIR

          # backup file name
          BACKUP_FILE=$BACKUP_DIR/backup-$DATE.zip
          zip -r $BACKUP_FILE data/

          # move backup file to backup directory
          mv #BACKUP_FILE $BACKUP_DIR
        '';
      };
    });
  };
}