Three things to fix before going live on Hydrogen

Hydrogen is fast — until you ship to prod and discover the three gotchas every team hits.

1. Cookie size on edge

Shopify's default cart cookie can balloon past Cloudflare's 4KB header limit when you add line-item attributes. Trim it before deploy.

2. Cart hydration

The default useCart hook re-fetches on every navigation. Pin it to a route segment, not the root layout.

3. The SEO trap

Hydrogen renders product pages on demand. Without a canonical sitemap.xml + Open Graph passthrough, Google indexes your fallback shell. We learned this once. Never again.

// Trim the cart cookie before it reaches the edge.
export function trimCart(cart: Cart): Cart {
  return {
    ...cart,
    lines: cart.lines.map(({ attributes, ...line }) => line),
  }
}