# Web Experiment: Cross-subdomain experimentation — Amplitude Changelog

Web experiments can now target multiple subdomains

Source: https://amplitude.com/en-us/releases/web-experiment-cross-subdomain-experimentation

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[Changelog](/releases)/Web Experiment: Cross-subdomain experimentation

ExperimentJul 15, 2026

# Web Experiment: Cross-subdomain experimentation

Web experiments can now target multiple subdomains

## What it is

**Description:** Web experiments can now target multiple subdomains.

**Why:** For web experiments, customers want to be able to run experiments consistently across their websites (e.g. a.example.com and b.example.com). Web experiments now maintain a consistent identity (i.e. bucketing id, behavioral targeting events) across the same eTLD+1 (e.g. \*.example.com), which allows end-users to be consistently assigned variants across subdomains.

**Where:** Web experiment

**Available in EUDC:** Yes

**When:** Enabled by default for web experiments created after 13th July 2026

Release details

- Release ID

  web-experiment-cross-subdomain-experimentation

- Shipped

  Jul 15, 2026

- Area

  Experiment

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