NetStutter – Network Throttling Simulator

Simulate slow and unstable network conditions on the current tab with one click.

WHAT'S NEW IN 1.2.0 Profiles are now the center of NetStutter. Save your own networks and timings once, then build Profiles from a network, a behavior, and optional API addresses. The Profile marked In use is applied when you turn a tab on; switch it in Settings or from the toolbar menu. With API addresses, only those exact requests (for example /api/orders) are slowed or go offline while the rest of the page stays at normal speed. Your existing settings and Profiles are carried over automatically. NetStutter is a focused network throttling simulator for developers and QA. Pick a Profile, then left-click the toolbar icon to turn network simulation on or off for the current tab. There is no popup. Each tab works independently. Enable NetStutter in Tab A while Tab B stays normal, or enable both with separate sessions. Clicking the icon again restores normal network conditions for that tab. PROFILES A Profile combines one network, one behavior, and optional API addresses. One Profile is In use: it is applied the next time you turn a tab on. Click Use in Settings, or right-click the NetStutter toolbar icon and choose a Profile under Switch Profile; the menu marks the Profile in use. Switching never turns a tab on or off and never changes a tab that is already running. NETWORK CONDITIONS Choose from 17 built-in network conditions covering Mobile, Wi-Fi, Home Broadband, and Offline. Save your own named networks with download and upload speeds in Mbps and latency in milliseconds. Editing a saved network updates every Profile that uses it the next time a tab is turned on. BEHAVIORS • Continuous: keep the condition active until you turn it off. • Random: start with normal network, wait a newly chosen time within your From/To range, apply the condition for a fixed duration, then repeat. • Interval: start with normal network, wait a fixed Every period, apply the condition for a fixed duration, then repeat. Use the built-in timings or save your own as named behaviors. ONLY THE REQUESTS YOU CHOOSE By default every request in an enabled tab uses the Profile's condition. In the Profile editor, choose Only matching requests and add up to 10 API addresses, copied from DevTools, such as /api/orders or https://shop.example/api/orders?id=1. Matching is exact: the path and the query must be the same, so /api/orders does not match /api/orders?id=1 or /api/orders/7. With Offline, only matching requests fail and the page itself stays online. PREDICTABLE Already running tabs keep the configuration they were turned on with until you turn them off and on again. Blue means Off, orange means armed and waiting with normal network, and red means the simulated condition is active. LOCAL AND PRIVATE Networks, behaviors, Profiles, and API addresses stay in local Chrome storage. NetStutter has no account, cloud sync, analytics, telemetry, advertising, external API, or remote code. It does not record requests, read request or response bodies, or save browsing history. API addresses are only passed to Chrome to decide which requests are affected; NetStutter does not inspect those requests. It briefly checks a tab's URL to determine whether the page is supported; the URL is not saved or transmitted. Chrome's debugger permission is used only to apply and clear network conditions on tabs you explicitly enable by left-clicking the toolbar icon. Chrome may display its standard debugging information bar. Browser cancellation of debugging can stop multiple enabled sessions; NetStutter then clears their local running states. NetStutter supports ordinary HTTP and HTTPS pages on Chrome 153 or newer. Chrome internal pages, Chrome Web Store pages, and other protected targets are unavailable for network simulation. It does not limit your whole computer or browser.