Quickstart

From zero to your first evaluated feature flag in five minutes. No infrastructure knowledge required.

Step 1 — Create your organization

When you first log in, Vexil will prompt you to create an organization. This is the workspace where all your flags, environments, and teammates live. Give it your project or company name and click Create.

Step 2 — Create your first flag

1. 1
   Click "New flag" in the dashboard

   You'll find it in the top-right of the Flags page.
2. 2
   Choose a type

   Start with Boolean — it\'s the simplest. Boolean flags are either on or off.
3. 3
   Set the flag key

   Pick a short, descriptive key like new-checkout. This is what your code will reference. Keys are permanent, so choose carefully.
4. 4
   Click "Create flag"

   Your flag appears in the list, disabled by default in all environments.

Step 3 — Enable the flag in an environment

Click on your new flag to open its detail page. You'll see a toggle for each environment (e.g. Development, Production). Flip the toggle in Development to enable it — this won't affect your production users.

Step 4 — Install the SDK in your app

# npm
npm install @vexilapp/sdk

# yarn
yarn add @vexilapp/sdk

# bun
bun add @vexilapp/sdk

Step 5 — Get your API key

Go to Settings → API Keys in the dashboard, click Create key, and copy it. This key tells the SDK which organization's flags to load.

Step 6 — Evaluate the flag in your code

import { Vexil } from '@vexilapp/sdk'

const ff = new Vexil({
  apiKey: process.env.VEXIL_API_KEY,
  baseUrl: 'https://your-api.example.com',
})

// Evaluate the flag for a specific user
const showNewCheckout = await ff.evaluate<boolean>('new-checkout', {
  userId: 'user_123',          // your user's ID
  environment: 'development',  // matches the env you enabled it in
})

if (showNewCheckout) {
  // render new checkout UI
}

What's next?

Gradual rollout

Try a Gradual flag type to release to 10% of users first — see Flag types.

A/B testing

Run an experiment to measure which variant drives more sign-ups — see A/B Testing.

Invite teammates

Go to Settings → Members to add your team with the right role.