# How to A/B test a Webflow site

> To A/B test a Webflow site, use Webflow's own add-on [Webflow Optimize](https://duelpilot.com/compare/duelpilot-vs-webflow-optimize) (testing plus AI personalisation), a Webflow-focused app such as [Optibase](https://duelpilot.com/compare/duelpilot-vs-optibase) (A/B tests with heatmaps and recordings), or a script-based tool such as Duelpilot, pasted into Site settings → Custom code → Head code. Duelpilot differs in who does the work: your own AI agent designs the variants, checks them on every device and monitors the results.

Last reviewed: 2026-10-29 · HTML version: https://duelpilot.com/guides/webflow-ab-testing

## Three ways to test on Webflow

### [Webflow Optimize](https://duelpilot.com/compare/duelpilot-vs-webflow-optimize)

*Webflow add-on*

AI-assisted A/B testing and personalisation (formerly Intellimize). AI Optimize serves the best variation per visitor in real time, with firmographic targeting through Demandbase and 6sense ([webflow.com](https://webflow.com/feature/optimize)).

[Duelpilot vs Webflow Optimize](https://duelpilot.com/compare/duelpilot-vs-webflow-optimize)

### [Optibase](https://duelpilot.com/compare/duelpilot-vs-optibase)

*Webflow app*

No-code A/B testing focused on Webflow, with a script for other builders, plus heatmaps, recordings and personalisation in the same tool ([optibase.io](https://www.optibase.io)).

[Duelpilot vs Optibase](https://duelpilot.com/compare/duelpilot-vs-optibase)

### Duelpilot

*Script in Head code*

One synchronous tag in Site settings → Custom code → Head code. Your own AI agent (Claude, ChatGPT, Cursor or another MCP client) installs it, proposes ideas, designs 2–4 variants and checks them on phone, tablet and desktop. You approve each launch, or autopilot launches within your guardrails.

[Agentic A/B testing](https://duelpilot.com/agentic-ab-testing)

## What your AI agent can do with each

If you want an AI agent to run tests, the difference is whether it can only read results or also design and submit tests. Each cell below links to its source.

As documented by each vendor (Webflow Optimize and Optibase checked 17 October 2026).

|  | Webflow Optimize | Optibase | Duelpilot |
|---|---|---|---|
| MCP server | [Read only](https://webflow.com/updates/mcp-optimize-analyze-aeo): Webflow's MCP can read Optimize experiments and results (announced 15 Oct 2026) | [Read only](https://www.optibase.io/blog/optibase-mcp-ai-assistant-integration), on all plans | Yes: research, design, previews, site checks and monitoring ([MCP A/B testing](https://duelpilot.com/mcp-ab-testing)) |
| Agent designs variants | [No](https://webflow.com/updates/mcp-optimize-analyze-aeo), only read access is announced | [No](https://www.optibase.io/blog/optibase-mcp-ai-assistant-integration), the MCP can't create or edit tests | Yes, 2–4 variants per idea, with preview links |
| Pricing | [$299/mo add-on](https://webflow.com/pricing) based on page views (25K–500K/month); non-Webflow sites through sales | [Basic $79/mth](https://www.optibase.io/pricing) ($66 billed yearly); more tiers on its pricing page | €9 (Starter) or €49 (Pro, with autopilot) per site per month; €0 until you launch your first test |

## Install Duelpilot on Webflow

1. In the Webflow dashboard, open the site → Settings (or in the Designer: W menu → Site settings) → Custom code.
2. In Head code, paste the snippet as the very first line, above anything already there. Put it in the site-wide Head code only, not also in a page's own custom code or an Embed element (that would be a duplicate).
3. Save changes. Saving doesn't go live; publishing does.
4. Publish to the webflow.io staging domain only, and let your agent run verify\_install there: it reads the page source (in the head, synchronous, the right key) and loads the page in a real desktop and mobile browser.
5. Then publish to your custom domain and verify again.

```html
<script data-cfasync="false" src="https://edge.duelpilot.com/s/YOUR_SITE_KEY.js"></script>
```

Your agent can do this with you in the Webflow dashboard: you log in, it fills in the field and stops before saving and before each publish. If the Custom code tab is locked, check your Webflow plan; upgrading is your decision. Without an agent, send the same three lines to your designer or agency: first line of Head code, no async or defer, publish to staging first. The site key is public.

### Webflow-specific things to check

- Verify on the published site (staging or custom domain), not in the Designer canvas.
- If verify\_install says the script is in the body, it was pasted in Footer code: move it to Head code.
- The webflow.io domain loads the script, which is enough for verifying, but its visits are only counted if that origin is one of the Duelpilot site's domains. Add every custom domain; www and non-www, and subdomains of a domain you added, are included automatically.
- Localised subdirectories (/de, /fr) share the domain; a locale on another domain must be added.
- Running Webflow Optimize or Optibase as well? Don't test the same elements with two tools at the same time.
- A cookie consent app may hold the script back until consent; verify\_install flags it, and how to classify the script is the site owner's call.
- Exported code hosted elsewhere is a plain HTML site: the tag goes first in the head of each page.

## After the install

Duelpilot's runtime hides only the elements under test, in every version including the original, and reveals each one as soon as its change is applied, so visitors see the variant without the original flashing first ([how anti-flicker works](https://duelpilot.com/guides/ab-testing-flicker)). Variant events go to your GA4 and other analytics as well as to Duelpilot's own counter, and results use sequential statistics that are safe to check every day ([sequential testing](https://duelpilot.com/guides/sequential-testing)).

## Which one to choose

- Choose Webflow Optimize if your marketing site is on Webflow and you want testing and AI personalisation, including firmographic targeting, inside the same platform.
- Choose Optibase if you want a native Webflow app with A/B tests, heatmaps and recordings in one place. Duelpilot records no visitors, so it has no heatmaps; it sends variant events to tools such as Clarity.
- Choose Duelpilot if you want your own AI agent to research, design, check and monitor the tests, on Webflow or any other site, at a flat price per site.

## Try Duelpilot with your own agent

Give your agent one line: [set up Duelpilot for my site using /agents.md](https://duelpilot.com/agents.md). It opens a workspace, installs and verifies the script, and drafts the first test; you approve it, then switch on autopilot if you like. Or [see pricing](https://duelpilot.com/#pricing).

**[Start for €0](https://duelpilot.com/login) · [Give it to your agent](https://duelpilot.com/#start)** (€0 until you launch your first test)

## FAQ

### Where do I put an A/B testing script in Webflow?

In Site settings → Custom code → Head code, as the first line, without async or defer. Save, publish to the webflow.io staging domain, verify, then publish to the custom domain.

### Can my AI agent create Webflow Optimize or Optibase tests?

Not according to their own pages (checked 17 October 2026): both MCP servers read tests and results only. Duelpilot's agent designs and submits tests; a person approves the launch, or autopilot launches within the owner's guardrails.

### Does Duelpilot work on Webflow CMS and localised pages?

Yes. It is one site-wide tag in Head code, so it runs on every published page, CMS collection pages included. Subdirectory locales share your domain; a locale on another domain must be added to the Duelpilot site.

### What does Duelpilot cost for a Webflow site?

€9 per month per site on Starter, €49 on Pro with autopilot, flat per site. It's €0 until you launch your first test: installing, ideas, designs and previews cost nothing.

## Sources

- [Webflow Optimize](https://webflow.com/feature/optimize) (checked 2026-10-17)
- [Pricing | Webflow](https://webflow.com/pricing) (checked 2026-10-17)
- [Webflow updates: MCP for Optimize, Analyze and AEO](https://webflow.com/updates/mcp-optimize-analyze-aeo) (checked 2026-10-17)
- [Optibase](https://www.optibase.io) (checked 2026-10-17)
- [A/B Testing Pricing | Optibase](https://www.optibase.io/pricing) (checked 2026-10-17)
- [Optibase MCP: Ask AI About Your A/B Tests in Plain English](https://www.optibase.io/blog/optibase-mcp-ai-assistant-integration) (checked 2026-10-17)

## Related

- [Duelpilot vs Webflow Optimize](https://duelpilot.com/compare/duelpilot-vs-webflow-optimize)
- [Duelpilot vs Optibase](https://duelpilot.com/compare/duelpilot-vs-optibase)
- [A/B testing without flicker](https://duelpilot.com/guides/ab-testing-flicker)
- [MCP A/B testing](https://duelpilot.com/mcp-ab-testing)