v135 · performance

Prefetch Tester

Build and inject live speculationrules scripts with target_hint. Configure rule type, target hint, and eagerness, then inject — watch which links become eligible and read the registered rule set. Toggle between with and without target_hint to see the eligibility change for target="_blank" links.

checking Speculation Rules… checking target_hint support…
Without target_hint, Chrome assumes every speculation rule targets the current browsing context. A link with target="_blank" navigates into a new tab — a different context — so the browser couldn't match a prerender started without target_hint: "_blank". Chrome 135 adds target_hint to both prefetch and prerender rule sets, so navigations into new tabs can be speculated on too.

Rule builder

Generated rule JSON

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Sample links — eligibility depends on target_hint matching target=""

URL target="" Eligible? Open
/v135/ (current tab) _self check →
/v135/…/target-hint/ (new tab) _blank check ↗
/features (named frame) my-frame check →
/v135/fetchlater-api/ (current tab) _self check →

Registered rule log

00:00:00Ready — click "Inject rule" to add a speculation rule.

With vs without target_hint

Without target_hint (pre-135)

{ "prefetch": [{ "source": "list", "urls": ["/next-page/"] }] } <!-- _blank links cannot be matched — browser assumes _self context always -->

With target_hint: "_blank" (Chrome 135)

{ "prefetch": [{ "source": "list", "urls": ["/next-page/"], "target_hint": "_blank", "eagerness": "moderate" }] } <!-- Browser can now speculatively prefetch for new-tab links! -->

Injected <script> elements

No rules injected yet.