Run the marketing site examples

The repository includes three example experiments for testing Fabric Experiments against a generic B2B marketing website:

• homepage-hero-cta — tests primary hero CTA text and destination.
• platform-positioning — tests homepage headline/subheadline positioning.
• docs-entrypoint — tests which docs link gets more engagement.

These examples are payload-driven. They do not change a live website until that website installs the web SDK and maps each payload to the relevant UI placement.

1. Install the CLI

npm install -g @fabricorg/experiments
fx --version

Expected:

fx 0.5.3

2. Validate the examples

cd examples/marketing-site
fx validate experiments/

Expected:

3 experiment(s) valid.

3. Start the local dev server

fx dev

By default this starts on http://127.0.0.1:8787.

If that port is already in use, choose another port:

fx dev --port 8788

4. Apply the examples

Open a second terminal:

cd examples/marketing-site
fx apply experiments/

Then check the manifest:

curl http://127.0.0.1:8787/manifest

If you used another port:

curl http://127.0.0.1:8788/manifest

You should see all three experiments in the manifest:

• docs-entrypoint
• homepage-hero-cta
• platform-positioning

5. Send test events

Send an exposure:

curl -X POST http://127.0.0.1:8787/v1/exposure \
  -H 'content-type: application/json' \
  -d '{"experimentId":"homepage-hero-cta","subjectId":"visitor-1","variantKey":"start-building","manifestVersion":1}'

Send a conversion:

curl -X POST http://127.0.0.1:8787/v1/conversion \
  -H 'content-type: application/json' \
  -d '{"subjectId":"visitor-1","eventName":"signup","value":1,"at":"2026-05-08T21:00:00.000Z"}'

Read the report:

fx report homepage-hero-cta

Common issues

EADDRINUSE: address already in use 127.0.0.1:8787

Another process is using the default port. Either stop it or run:

fx dev --port 8788

To find the process:

lsof -nP -iTCP:8787 -sTCP:LISTEN

Manifest shows the wrong experiment

fx dev serves the workspace it was started from. If your manifest shows a different experiment, stop the old dev server and start it from examples/marketing-site:

cd examples/marketing-site
fx dev

Connecting these examples to a website

The YAML files define experiment payloads. A live website needs a small SDK integration that:

1. fetches the manifest,
2. activates the relevant experiment,
3. reads the variant payload,
4. updates the matching UI placement,
5. emits exposure and conversion events.

Example placements:

• hero-primary-cta changes the main homepage CTA.
• hero-headline changes the homepage headline and subheadline.
• nav-docs-link changes the docs navigation link.