@koryla/netlify

A/B testing for Netlify sites with zero flicker. Runs on Netlify Edge Functions (Deno).

Installation

npm install @koryla/netlify

Setup

1. Add environment variables

In your Netlify dashboard → Site settings → Environment variables:

KORYLA_API_KEY   = sk_live_...
KORYLA_API_URL   = https://your-koryla-app.vercel.app

Or in netlify.toml:

[build.environment]
  KORYLA_API_URL = "https://your-koryla-app.vercel.app"
# KORYLA_API_KEY should be set via the dashboard (never commit secrets)

2. Create an edge function

// netlify/edge-functions/koryla.ts
import { korylaMiddleware } from '@koryla/netlify'

export default korylaMiddleware({
  apiKey: Deno.env.get('KORYLA_API_KEY')!,
  apiUrl: Deno.env.get('KORYLA_API_URL')!,
})

export const config = {
  path: ['/', '/pricing', '/landing'],
}

3. Create your variant pages

Your variant pages must be real pages in your site:

src/pages/
  index.astro        ← control  (base_url: https://acme.com/)
  variant-b.astro    ← variant  (target_url: https://acme.com/variant-b)

Works with any Netlify-hosted framework: Astro, SvelteKit, Nuxt, plain HTML.

4. Create the experiment in Koryla

Go to your Koryla dashboard → New experiment → set to Active.

How it works

User visits /
     │
     ▼
Netlify Edge Function (runs at Deno edge, before your site)
     │
     ├── fetches experiment config from Koryla API (cached 60s)
     ├── reads variant cookie — if present, reuses it
     └── assigns variant by weight, rewrites via context.rewrite()
     │
     ▼
Netlify serves /variant-b content
Browser sees original URL (/) — no redirect, no flicker