Browser compatibility

Foil targets current evergreen browsers. It is designed for modern browser runtimes that support JavaScript, WebAssembly, and the transport APIs required by the client bundle.

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Supported versions

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What Foil requires

In practice, Foil expects a modern browser with:

• JavaScript enabled
• WebAssembly support
• TextEncoder and TextDecoder
• Modern fetch support for API transport
• Event APIs used for interaction collection

Some probes and correlation features may work better when browsers also allow cookies, storage, and richer graphics or audio APIs, but those are not equally available on every engine.

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Rollout guidance

If your traffic mix includes Safari, Firefox, or mobile-heavy traffic:

1. Start in report mode.
2. Observe result distribution by browser family, using latest_decision.verdict on list responses or decision.automation_status on session-detail responses.
3. Validate real user flows on your highest-volume browsers and devices.
4. Enforce gradually, beginning with the highest-confidence automated sessions and the most abuse-sensitive endpoints.

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Embedded browsers and webviews

Foil can run in embedded contexts, but compatibility varies by host app and runtime. If you rely on:

• iOS webviews
• Android webviews
• in-app browsers
• Electron or other embedded shells

validate them explicitly before you depend on enforcement behavior.

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What’s next

• Browser SDK — loading and initialization
• Testing your integration — simulate bot traffic across browsers
• Going to production — rollout checklist