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Install the SDK

The SDK (Software Development Kit) is what lets you build and preview apps on your own computer. Getting set up takes about 5 minutes.

You'll do everything from a terminal, a text window where you type commands.

How to open a terminal
  • Windows: press the Windows key, type powershell, and press Enter.
  • macOS: press Cmd + Space, type terminal, and press Enter.
  • Linux: open your Terminal app (often Ctrl + Alt + T).

A window opens with a blinking cursor. That's where every command on this page goes, one line at a time, each followed by Enter.

1. Requirements​

  • Python 3.9 or newer
  • Git (or use GitHub's "Download ZIP", shown below)

Installing Python​

Download it from the official site, python.org. It's a normal installer:

python.org/downloads

Use python.org, not the Microsoft Store

Install Python from python.org, not the Microsoft Store. The Store version puts the gdn command in a hidden folder that isn't on your PATH, so gdn reads as "not recognized" even after a perfectly successful install. If you already used the Store version, don't worry, python -m gdn still works (see step 3), but python.org is the smoother path.

Tick "Add python.exe to PATH"

On the first screen of the Python installer, tick "Add python.exe to PATH" before you click Install:

Add python.exe to PATH

If you miss it, Windows won't find python or gdn, and nothing below will work. (If you already installed without it, just re-run the installer and check the box.)

Open a new terminal window (so it picks up the new PATH) and check it worked:

python --version

You should see Python 3.9 or newer. On macOS/Linux, try python3 --version if python isn't found.

Installing Git​

Git downloads the app repository, and later publishes your app. First check whether you already have it, type this in your terminal:

git --version

If you see a version number, you're set, skip to the next step. If it says "command not found" or "not recognized", install it:

Download and run the installer from git-scm.com/download/win and accept the defaults. It also installs Git Credential Manager, which handles your GitHub sign-in for you the first time you publish, so there's no token to set up.

Open a new terminal afterward and run git --version again to confirm.

You'll want a free GitHub account

Publishing an app opens a pull request on GitHub, so make a free account at github.com if you don't have one. You don't need it to build and preview locally, only to publish.

2. Get the code​

Your apps are folders inside the GDN repository, so start by downloading it:

git clone https://github.com/glance-led-dev/glance-dev-network.git
cd glance-dev-network

No Git? On the GitHub page, click Code, then Download ZIP, unzip it, then open a terminal in that folder.

Use a normal terminal, not "Run as administrator"

Open a plain terminal, not an administrator one. An admin prompt starts in C:\Windows\System32, and cloning there drops the whole repo into a Windows system folder. Clone into an ordinary place instead, like C:\Users\<you>\Documents.

No fork to set up

Clone the main repo above and you're ready to build. When you publish, Glance Dev Studio creates your own fork automatically and sends the pull request from it, so there's no extra git setup. See Submit your app.

3. Install gdn​

From the repository folder you just entered, run:

pip install -e .

That single command installs everything GDN depends on automatically, so you normally never touch these by hand. For reference, the dependencies are:

PackageVersionWhat it does
Pillow>=9Renders your panel to PNG images
PyYAML>=6Reads your manifest.yaml
Flask>=2.2Runs the local preview and Studio servers
jsonschema>=4.18Validates the manifest
starlark-pyo3>=2026.1Runs your app.star in the Starlark sandbox
requests>=2.28Fetches data for apps that call an API

pip install -e . pulls all of these in for you. If you'd rather install them yourself, you can do it in one line instead:

pip install Pillow PyYAML Flask jsonschema starlark-pyo3 requests
macOS: "externally-managed-environment"?

On a Mac, Python is usually Homebrew's, which blocks installing into it — pip install fails with error: externally-managed-environment. Use a virtual environment (this is the recommended setup on macOS anyway):

python3 -m venv .venv
source .venv/bin/activate      # do this in EVERY new terminal
pip install -e .

The .venv only applies to the terminal you activate it in. Each time you open a new terminal to run gdn (including gdn studio), cd into the folder and run source .venv/bin/activate again first.

Then check it works:

gdn version

You should see gdn 0.1.0. You now have the toolkit: gdn studio, gdn new, gdn preview, and more. See them all in the CLI commands guide.

"gdn is not recognized"? You're still fine

If the install said "Successfully installed" but gdn version says "not recognized", the command simply isn't on your PATH (common with Microsoft Store Python). Nothing is broken and you don't have to fix it to keep going, use either of these:

  • Run everything with python -m gdn instead of gdn, for example python -m gdn version or python -m gdn studio. This always works.
  • Or double-click studio.bat in the repo folder (macOS: studio.command, Linux: studio.sh) to open Studio without needing gdn on your PATH.

To make plain gdn work everywhere, install Python from python.org with "Add python.exe to PATH" ticked (see step 1), then reopen your terminal.

Troubleshooting​

  • "pip is not recognized" try python -m pip install -e . (or py -m pip install -e . on Windows).
  • "gdn is not recognized" close and reopen your terminal first. If it still fails, python -m gdn version always works. On Windows this almost always means the "Add python.exe to PATH" checkbox was missed, re-run the Python installer and tick it.
  • "attempted relative import with no known parent package" you typed python studio.py by hand from inside the gdn folder. Open Studio with gdn studio from the project folder instead, or double-click the launcher for your system (studio.bat, studio.command, or studio.sh). See Opening Glance Dev Studio.
  • Studio's Save fails with "Permission denied" and a C:\Windows\System32\... path the repo is inside a protected Windows system folder. It lands there if you cloned from an administrator terminal (which opens in System32). Move the whole glance-dev-network folder to your Documents or Desktop, open a normal (non-admin) terminal there, and run gdn studio again.
  • "Parse error: cannot use reserved keyword import" app.star is Starlark, not Python, so import and Python libraries aren't allowed. Use c and ctx (and the HTTP helper for web data) instead.
  • "externally-managed-environment" (common on macOS with Homebrew Python) or other permission errors on install use a virtual environment (and remember to re-activate it in each new terminal, including before gdn studio):
python -m venv .venv
.venv\Scripts\activate
pip install -e .

Next​

Head to Getting started. You'll have a working app on screen in about five minutes.