Monitor
See live upload and download activity by app across outbound TCP and UDP traffic.
About Throttlr
Per-app bandwidth control, built for macOS.
Throttlr is an independently built Mac utility that makes network activity visible and gives each app its own upload, download, and blocking controls.
What Throttlr does
Direct controls for a shared connection.
Slow a background sync without touching a call, find the app moving data, test a bandwidth-constrained workflow, or stop one app from reaching the network.
Throttle
Set separate upload and download caps for one app or for broader traffic scopes.
Block
Temporarily stop upload, download, or both directions for a selected app or scope.
How it works
Traffic stays on your Mac.
Throttlr uses Apple's Network Extension framework to apply your rules in a local system extension rather than sending network traffic to a remote service.
- 1
An app opens a connection
An eligible outbound TCP or UDP flow begins in an app on your Mac.
- 2
macOS routes the flow locally
After you approve the system extension, Apple's Network Extension framework sends the eligible flow through Throttlr's local proxy provider.
- 3
Throttlr identifies its scope
The provider associates the flow with its source app and classifies its destination as internet or local-network traffic.
- 4
Your selected policy is applied
Throttlr monitors the flow, applies independent upload and download limits, or blocks the selected direction.
- 5
Permitted traffic continues
Traffic that is not blocked continues to its destination while aggregate activity and runtime statistics remain available locally.
A macOS connection boundary
Connections opened before the current proxy provider started may remain outside Throttlr because of an Apple Network Extension limitation. Keeping Launch at Login enabled helps Throttlr start before other apps. When needed, Throttlr prompts you to quit and reopen an app so its new connections can enter through the provider.
Privacy by architecture
Network data stays local.
Traffic contents, browsing activity, and per-app traffic statistics are not sent to Throttlr servers. The app processes traffic and maintains its runtime statistics locally on your Mac.
Trial and paid-license activation use separate online licensing services. The Privacy Policy explains the installation, licensing, purchase, and support data involved.
Built for macOS
One approved extension.
Throttlr requires macOS 15 or newer. Its signed installer includes a system extension that macOS asks you to approve before traffic monitoring and controls can begin.
Bandwidth limits constrain throughput. They do not reproduce every network property, such as latency, packet loss, or DNS failure. See the slow-network testing guide for accurate test boundaries.
Independent studio
Japard Labs
Throttlr is developed and officially distributed by Justin Yap. Japard Labs is the publishing brand used for Throttlr. The product is built around a simple idea: a shared internet connection works better when you can see which apps are using it and decide how much access each app should have.
Justin built Throttlr after looking for a NetLimiter-style workflow on macOS: see an app's live traffic, cap its upload or download speed, or temporarily block it. Throttlr is an independent product and is not affiliated with NetLimiter or Locktime Software. Read the honest NetLimiter alternative for Mac comparison.
See what your apps are doing with the connection.
Download Throttlr for monitoring and a 14-day trial of per-app throttling and blocking. No sign-up or credit card is required for the trial.
Need help first? Read the FAQ or email support@throttlr.app.