iOS app
NetCap: Internet Speed Limiter
NetCap puts a ceiling on your iPhone's download and upload speed, adds latency and packet loss on demand, and lets you save the settings as profiles - so you can see how an app behaves on a bad connection instead of guessing. It runs as an on-device network extension with no remote server in the path.
Throttle & Test Your Network
Coming to the App Store. This page is the support and legal home for it.
What it does
A connection you can turn down on purpose
Download and upload caps
Set a ceiling on each direction independently, anywhere from 64 kbps up to 100 Mbps down and 50 Mbps up. The limiter meters real traffic to hold that rate.
Added latency and packet loss
Add up to 1,000 ms of round-trip delay and up to 10% packet loss, so you can see how an app copes with a connection that is slow and unreliable rather than just slow.
Presets and saved profiles
Five built-in network presets, from Very Slow to Fast 4G, plus your own named profiles with an icon and the exact numbers you need to reproduce.
Live session metering
Bytes down, bytes up, session duration, open connections and simulated drops - measured at the limiter itself, not estimated from a system counter.
No remote server in the path
Traffic is queued, delayed and metered inside an on-device network extension, then forwarded straight to the internet. Nothing is proxied through us.
Diagnostics for when it matters
TCP connections, UDP bindings, packets the limiter cannot carry and current queue depth, all visible while the limiter runs.
Presets
Five networks, ready to switch on
Every preset is a real set of numbers you can read before you apply it, and duplicating one gives you an editable copy of exactly those values.
| Preset | Download | Upload | Latency | What it feels like |
|---|---|---|---|---|
| Very Slow | 256 kbps | 128 kbps | 300 ms | Barely usable connection |
| 2G | 512 kbps | 256 kbps | 250 ms | Very slow connection |
| 3G | 1 Mbps | 512 kbps | 150 ms | Typical mobile connection |
| Slow 4G | 5 Mbps | 2 Mbps | 80 ms | Limited mobile connection |
| Fast 4G | 10 Mbps | 5 Mbps | 40 ms | Moderate connection |
Or set your own
A custom profile takes any value inside these ranges, by slider or by typing an exact number.
- Download
- 64 kbps - 100 Mbps
- Upload
- 64 kbps - 50 Mbps
- Added latency
- 0 - 1,000 ms
- Packet loss
- 0 - 10%
Honest limits
What the limiter cannot reach
iOS decides what a third-party network extension is allowed to carry. These are the consequences, and the app states them on screen while it runs.
- Traffic to your local network is not limited.
- Ping and traceroute are not carried through the limiter.
- Some system services stay outside any third-party network extension.
- Added latency is split across both directions, roughly half each way.
- Packet loss is applied by discarding IP packets before they are forwarded.
- Switching between Wi-Fi and cellular resets open connections.
Support
Frequently asked questions
Is NetCap a VPN?
No. NetCap uses Apple's Network Extension framework, which is the same mechanism a VPN app uses, so iOS asks for permission to add a network configuration and shows a VPN indicator while the limiter runs. But there is no remote server: your traffic is shaped on the device and sent straight on. NetCap does not hide your IP address, encrypt your traffic, filter content or make you anonymous.
Why does it ask for permission to add a VPN configuration?
That is how iOS gates the Network Extension framework. Without that permission an app cannot see or shape your traffic at all. Granting it lets the on-device extension run; it does not send anything to us. You can revoke it at any time in Settings › General › VPN & Device Management, or remove the configuration from inside NetCap.
Does it slow down other people on my Wi-Fi?
No. The limit applies to traffic from this device only. It is not a router setting and it does not touch anyone else's connection.
How accurate is the limit?
The limiter meters bytes as they pass through it, and the session figures are measured rather than estimated. Actual throughput can still differ from the number you set: iOS schedules the extension, some traffic never enters it at all, and your underlying connection may be slower than your cap anyway.
Does it work in the iOS Simulator?
No. Network extensions do not run in the Simulator, so NetCap has to run on a physical iPhone to limit real traffic.
What does it cost?
The 3G preset is free, so you can confirm the limiter works on your device before paying anything. Everything else - the other presets, unlimited custom profiles, and upload as well as download limits - is unlocked by a single one-time purchase. There is no subscription.
Can I use the purchase on my other devices?
Yes. The unlock is tied to your Apple Account, so it restores on any device signed in to the same account. Settings › Restore Purchase does it manually if it does not happen automatically.
What data does NetCap collect?
None. There is no account, no analytics and no server of ours. The extension never records the addresses you visit or the contents of your traffic, and session statistics are byte counters held in memory that are cleared when the limiter stops. The full statement is in the privacy policy.
Which iOS versions and languages are supported?
NetCap requires iOS 16 or later on iPhone. The interface is available in English, Simplified Chinese, Japanese, German, French, Spanish and Korean.
How do I get help or report a bug?
Email support@codivolabs.com with your device model, your iOS version, the profile you were running and what you saw. The Diagnostics screen in Settings has the numbers that are usually needed to reproduce it.