The developer path

From first event to permanent code.

Capture an event, assign the variant before first paint, measure what happened, and merge the winner into your code. The Web SDK, Server Events API, MCP server, and GitHub workflow all use the same experiment.

Start free Pricing

No credit card to start.

Capture customer behavior

Bring web, mobile, and backend events together.

The Web SDK captures browser events and runs browser-applied experiments. The Mobile SDK captures app sessions and attribution. The Server Events API records purchases and activations from your backend. Apex ties all three to one customer record.

Web install guide · Mobile install guide · Server Events docs

Apply the variant

Show the assigned variant before the page appears.

Use the snippet when Apex can change an element that’s already on the page. Use @apex-inc/next when the variant lives in application code. Server-side assignment puts the variant in the first HTML, so the page doesn’t switch after it loads.

Choose who changes the pageNo deploy

PricingDocs

Variant B · assigned

See customer value clearly.

Connect your first source and see which customers are becoming more valuable.

Start freeRendered on first paint

<head>No deploy

<style id="apex-antiflicker">
  html { opacity: 0 !important; }
</style>
<script
  src="https://your-apex-domain/api/apex-js?key=YOUR_KEY"
  async
></script>

The snippet assigns the variant, applies it, then shows the page.

1HTML parses
2Snippet assigns B
3Page reveals B

See browser-applied experiments · Wire a code experiment

Work from your editor

Plan the experiment without leaving your editor.

With the open-source Apex MCP server, Cursor, VS Code, Claude, and other MCP clients can inspect events, check the wiring, and plan the experiment. Apex gives your agent the experiment IDs and implementation steps. Your agent writes the code, and you review it.

CursorExample session · Apex MCP connected

YouPlan a homepage experiment from what we already know.

Apex

Found 3 past experiment results
Primary metric: paid signup
Experiment plan ready

@apex-inc/mcp-serverInstall in Cursor Install in VS Code

Read the MCP docs · Install Apex MCP

GitHub × Apex

Merge the variant. Measure it. Keep the winner.

Link the pull request to the experiment. Merging makes it ready to run. The first recorded Production visit starts measurement. Apex compares the variant with the control. If the variant wins, Apex opens a templated Graduation PR that keeps it and removes the code that chose between variants. You review every change.

shop / websiteExample

Try a shorter homepage hero #42

Openshop wants to merge 1 commit into main from apex/exp_home_hero

Apex linked this pull request to Homepage hero

All checks have passed4 successful checks

Merge to make the experiment readyMeasurement starts on the first real visit.

Apex experiment

Draft

2Deploy

3Live

4Decision

5Promote

6Graduate

See the Graduation Pipeline · Read the implementation guide

One API everywhere

The dashboard and SDKs use the same APIs you do.

Call REST directly when you need control. When Apex needs to call your system, it sends a signed webhook you can verify.

Apex APIDashboard, SDKs, and MCP use this API

Choose an operation

Your backendPOST /api/v1/events

{
  "events": [{
    "type": "purchase_completed",
    "visitorId": "vis_abc123",
    "data": {
      "value": 99,
      "currency": "USD"
    }
  }]
}

Apex response200 OK

{
  "data": {
    "received": 1,
    "duplicates": 0
  },
  "metadata": { "batchSize": 1 }
}

Apex adds the purchase to the same customer record used by the Web and Mobile SDKs.

Dashboard
Web SDK
Mobile SDK
MCP
Your code

Open the quickstart · Read the API docs · Verify webhooks · Read the Apex Spec

Your move

Send one real event. Run one real experiment.

Start where customers act: your website, mobile app, or backend. Add Apex MCP and GitHub when you're ready to keep a winner through a reviewed Graduation PR.

Start free View pricing