---
title: "Cloudflare Workers vs Vercel Edge Config for A/B Testing"
description: "Both run the split at the edge with zero flicker. The real difference is which platform you're already committed to, and Landtest is worth knowing about as a third option that isn't tied to either."
canonical: https://landtest.dev/blog/cloudflare-workers-vs-vercel-edge-config
last-updated: 2026-10-30
---

# Cloudflare Workers vs Vercel Edge Config for A/B Testing

> Both run the split at the edge with zero flicker. The real difference is which platform you're already committed to, and Landtest is worth knowing about as a third option that isn't tied to either.

Cloudflare Workers and Vercel Edge Config both solve A/B test flicker the same way — assignment happens server-side, before the response reaches the browser — but they're tied to different platforms and use different mechanisms. Workers rewrites HTML in transit via `HTMLRewriter`, which is framework-agnostic and works regardless of your origin. Edge Config reads variant assignment data at the edge inside Vercel's middleware, with [sub-15ms P99 reads](https://vercel.com/blog/zero-cls-experiments-nextjs-edge-config) documented directly by Vercel. Neither is objectively better; the choice usually comes down to which platform you're already running on.

This is neutral comparison content from the Landtest team — we're disclosing that upfront since Landtest is a third option mentioned below, not because either Cloudflare or Vercel is a competitor we're positioning against.

## Cloudflare Workers

Best if your origin isn't exclusively Next.js/Vercel, or you're already running Cloudflare in front of multiple properties and want one A/B testing approach across all of them. The tradeoff is that you're writing and maintaining `HTMLRewriter` rules yourself — a real engineering investment, not a config toggle.

## Vercel Edge Config

Best if you're fully on Vercel and want the tightest possible integration with Next.js middleware, with Vercel's own infrastructure handling the read path. The tradeoff is platform lock-in — this doesn't transfer if you ever move off Vercel — and the split logic still lives in `middleware.ts`, which can get crowded alongside auth and locale routing. See [A/B testing without middleware conflicts](/blog/ab-test-nextjs-landing-page-without-middleware-conflicts) if that's a concern.

## Landtest, as a third option

If you don't want to own edge-rewrite code or middleware logic on either platform, Landtest runs the split through your deploy pipeline instead — variant generated as a branch, split configured at the hosting layer, both independent of whether you're on Cloudflare or Vercel specifically.

## Which one to pick

If you're Vercel-committed, Edge Config is the tightest integration. If you're Cloudflare-committed or need framework-agnostic edge rewriting, Workers is the stronger fit. If you'd rather not own either the Worker or the middleware logic, that's where Landtest's deploy-pipeline approach differs from both.

## FAQ

**Which is faster, Cloudflare Workers or Vercel Edge Config?**
Both report very low latency (Workers: sub-millisecond bucketing; Edge Config: sub-15ms P99 reads) — in practice the difference is unlikely to be the deciding factor versus which platform you're already on.

**Can I use Cloudflare Workers in front of a Vercel-hosted Next.js app?**
It's architecturally possible but adds complexity — you'd be layering Cloudflare's edge logic in front of Vercel's own edge network, which is unusual outside specific multi-CDN setups.

**Does Landtest require either Cloudflare or Vercel?**
No — Landtest's split runs through your deploy pipeline and works with any host.

---

Related: [Cloudflare Workers A/B testing vs Landtest](/blog/cloudflare-workers-ab-testing-vs-landtest) · [Vercel Edge Config vs Landtest](/blog/vercel-edge-config-vs-landtest) · [Landtest for A/B testing](/ab-testing)