How to manage dependencies in Replit

Open the Shell tab and use your language's package manager to install dependencies. For Node.js projects, use npm install. For Python, use pip install. These install packages into your project directory (node_modules for npm, a virtual environment for pip). Always use --save or --save-dev flags with npm so dependencies are recorded in package.json. For pip, generate a requirements.txt file after installing packages so the list is reproducible.

1# Node.js — install and save to package.json
2npm install express cors dotenv
3npm install --save-dev jest typescript
4
5# Python — install and freeze to requirements.txt
6pip install flask requests sqlalchemy
7pip freeze > requirements.txt

Replit provides a graphical package manager accessible from the Tools dock. Click the Dependencies tool (or search for 'Packages' in the search bar) to open it. Type a package name to search, then click the install button. The GUI handles the installation command for you and adds the package to your dependency file automatically. This is useful for beginners or when you want to browse available packages without memorizing exact names.

Some packages need system libraries that npm or pip cannot provide — for example, image processing libraries need libvips, database clients need PostgreSQL headers, and PDF generation needs poppler. Replit uses Nix to manage these system-level dependencies. Open .replit (enable 'Show hidden files'), then open replit.nix. Add the required system packages to the deps array. Search for available packages at search.nixos.org/packages. After editing replit.nix, type 'exit' in Shell to restart the environment and load the new packages.

1# replit.nix — system-level dependencies
2{ pkgs }: {
3  deps = [
4    pkgs.nodejs-20_x
5    pkgs.nodePackages.typescript-language-server
6    pkgs.python311
7    pkgs.postgresql
8    pkgs.libvips
9    pkgs.ffmpeg
10    pkgs.imagemagick
11  ];
12}

For simpler system dependencies, you can skip editing replit.nix and add packages directly in the .replit file under the [nix] section. This is a quicker method for small additions. The packages listed here are installed alongside those in replit.nix. Make sure the Nix channel is set to a recent stable version to ensure package compatibility.

1# .replit file — quick Nix packages
2[nix]
3channel = "stable-24_05"
4packages = ["cowsay", "htop", "curl", "jq"]

To ensure dependencies install automatically whenever the Repl starts (especially after a restart or when a collaborator opens the project), add an onBoot command to your .replit file. This runs once at startup and handles the initial setup. For projects that use both npm and pip, chain the commands with &&.

1# .replit file
2onBoot = "npm install && pip install -r requirements.txt"

Large projects with many dependencies can hit storage limits, especially on the Starter plan (approximately 2 GiB). Check your current storage usage by clicking the Resources panel (stacked computers icon in the left sidebar). It shows RAM, CPU, and storage breakdown. To reduce dependency size, remove unused packages with npm prune or pip uninstall, avoid installing heavy packages globally, and use .replit hidden to hide large directories like node_modules from the file tree without deleting them.

1# Check disk usage from Shell
2du -sh node_modules/
3du -sh .local/
4
5# Remove unused npm packages
6npm prune
7
8# Remove a specific unused package
9npm uninstall unused-package-name