Support & FAQ

Need help with Jitter Box? You’re in the right place.

Quick troubleshooting

“Could not connect” when I run a test

• Make sure the receiving device is actually listening: on a Mac, enable “Listen for incoming tests” in Settings; on a Linux box or NAS, start the free command-line receiver. (The iPhone app is a client only — it runs tests against a receiver, it can’t be one.)
• Make sure both devices are on the same network (Wi-Fi, Ethernet, or VPN).
• Check that the receiver’s firewall (on a Mac: System Settings → Network → Firewall) isn’t blocking incoming connections on the port you picked (default 7878).
• Try the receiver’s IP address (e.g. 192.168.1.42) instead of its hostname — some routers don’t expose .local Bonjour names.

“Could not connect” from my iPhone

• The first time you run a test, iOS asks for Local Network permission. If it was denied, every test fails: open Settings → Privacy & Security → Local Network and make sure Jitter Box is switched on.
• iPhones drop Wi-Fi aggressively to save power. If the test fails immediately, wake the screen, confirm you’re on the same Wi-Fi as the receiver, and try again.

“The numbers look too low”

• The test reports the actual speed of the link between the two devices. Wi-Fi is often slower than your ISP plan, especially in a busy 2.4 GHz channel or far from the router. Try Ethernet on one or both ends to see what the wired link can do.
• 4 parallel TCP streams saturate gigabit easily; if you have a 10 Gbps link, try increasing “Parallel streams” to 8 or more in Settings.

“The receiver toggle won’t stay on” (Mac)

• The first time you enable the receiver, macOS may ask for Local Network permission. Open System Settings → Privacy & Security → Local Network and make sure Jitter Box is on the list and switched on.
• If you’re running Jitter Box out of ~/Downloads and macOS shows a Gatekeeper warning, move the app to /Applications and reopen it (right-click → Open the first time).

“Launch at login” doesn’t work (Mac)

• Open System Settings → General → Login Items & Extensions and make sure Jitter Box appears under “Open at Login” with its toggle on. If the toggle was previously denied, the in-app switch in Jitter Box’s Settings can’t override that — you have to re-enable it in System Settings first.

Frequently asked

Does it work over a VPN?

Yes, as long as the two devices can see each other on the VPN’s address space. The app uses plain TCP, so Tailscale, WireGuard, or any other VPN that routes addresses between peers will work — it’s a handy way to measure the real throughput of the tunnel itself.

Does it work over the public internet?

In theory yes — if the receiver is reachable on its public IP and the relevant port is forwarded. In practice, the app is designed for LAN use; running a public-facing speed test receiver has obvious security implications and is not officially supported.

Will it test against speedtest.net or fast.com?

No. By design Jitter Box only talks to other Jitter Box installs (or the free companion Go CLI that speaks the same protocol). The whole point is to measure the link you actually care about, not the path to a server in someone else’s data centre.

What’s the data I see in “History”?

Every test you’ve ever run, with the four headline numbers (ping, jitter, download, upload), the host you tested against, and the date. All stored locally on your Mac or iPhone; nothing leaves the device.

Contact

Email: help@jitterbox.app

— Cloudmanic Labs, LLC