RETRO//CAPTURE Guide
The free companion app for RETRO//STRESS. Pick a program on your computer, record the network traffic it sends, and replay that traffic against your own server at any scale.
What is RETRO//CAPTURE?
RETRO//CAPTURE sits between your computer and the RETRO//STRESS platform. You use it to:
- Record the real network traffic a program is sending — a game, a browser, any app.
- Save it as a reusable chain on your RETRO//STRESS account.
- Launch a stress test that replays that exact traffic at your own target, at the scale you choose.
It's the fastest way to build a realistic stress test without writing anything by hand. Comes in three flavors you can mix and match:
- Desktop app — Windows, macOS, and Linux. This is where you'll do most of the work.
- Mobile app — Android and iOS. For launching saved favorites on the go.
- Terminal app — a lightweight version for remote servers.
Install the app
Head to the RETRO//CAPTURE downloads page and grab the version for your system:
| Platform | What to do |
|---|---|
| Windows | Download the installer. It will prompt you to install Npcap the first time — that's the driver the app uses to record traffic. |
| macOS | Download the .dmg, drag the app into Applications, and open it. macOS may ask for permission the first time you record. |
| Linux | Download the archive, extract, and run the app. If you don't already have libpcap, install it with your package manager (apt install libpcap-dev on Debian/Ubuntu). |
| Android | Install from the Play Store link on the downloads page. |
| iOS | Install from the App Store link on the downloads page. |
Link your account
The app never asks for your access key. Instead, you approve it in your browser — exactly once per device.
A RETRO//STRESS approval page opens in your browser.
You'll see "Link RETRO//CAPTURE?" with the name of the device asking for access. If that looks right, click Approve.
The browser sends you back to the app and it unlocks. You only do this once — the app remembers until you unlink it.
Your first test
The easiest way to get a feel for the app is Quick Test — it handles everything in one go. Make sure you have a target you're authorized to test, then:
The app shows every program on your computer that's currently talking to the network, with how many connections each one has open. Click the one whose traffic you want to replay — for example, a game client.
You'll see three mode cards. Pick Quick Test — the rocket icon.
Type the IP address and port you want to hit, pick how long the test should run, and how many parallel connections you want. Click Launch.
The app records for about 10 seconds, uploads the recording, and kicks off the test. Monitor progress from Panel → Active Tests in your dashboard.
The three modes
After you pick a program, you choose what to do with it. The three modes are:
| Mode | What it does | Pick it when |
|---|---|---|
| Capture Only 💾 | Records traffic and saves it as a file on your computer. | You just want the raw recording to inspect or keep for later. |
| Capture + Chain 🔗 | Records traffic and turns it into a saved chain on your account — but doesn't launch a test. | You want to save a chain for later, tweak it in the Chain Builder, or reuse it from a different device. |
| Quick Test 🚀 | Record, build the chain, and launch the test — all in one shot. | You already know your target and just want results. |
A "chain" is just a saved recording. Once it's on your account you can launch it again later from the dashboard, share it between your devices, or open it in the Chain Builder to edit it by hand.
Favorites & mobile
Tests you run regularly can be saved as favorites. A favorite remembers the program, the target, and your usual settings — next time you just tap it.
- Create a favorite — after launching a test, tap the star icon in the confirmation screen.
- Launch from favorites — the favorites tab lists everything you've saved. Tap one, adjust anything you want, and launch.
- Sync — favorites on each device are kept separately, so you can have different saved targets on desktop and mobile.
The mobile app is built around favorites. It doesn't record traffic itself — instead, you record on desktop, save a favorite, then launch it from your phone when you need it. Handy for re-running a test while you're away from your desk.
Tips for better chains
- Capture with the program in a "real" state. If you're recording a game, make sure you're actually logged in and moving around — not sitting on the menu screen. The chain is only as realistic as the traffic you record.
- Keep captures short. 10–15 seconds is usually plenty. Longer captures make bigger chains without adding much variety.
- One program at a time. Close anything else that's noisy (updaters, Discord, Steam) so the recording isn't diluted.
- Name your chains. In Capture + Chain mode, give the chain a clear name
like
myapi v2 POST /login. Future-you will thank present-you. - Verify your target. Use the network tools in the dashboard (ping, TCP ping, HTTP check) to confirm your target is reachable before you launch.
Troubleshooting
"Permission denied" when I hit record
Recording traffic needs admin rights. On Windows, right-click the app and choose
Run as administrator. On macOS, approve the prompt when it appears. On
Linux, either run with sudo or ask your system admin to grant the app the
required permissions.
My program doesn't show up in the list
The list only shows programs that are currently sending or receiving traffic. If yours is idle, do something in it (load a page, open a menu, send a message) and click Refresh.
Approval page says my plan isn't eligible
Launching captured chains needs a plan with advanced methods. Either upgrade from the Pricing page, or use Capture Only mode to save recordings locally without launching.
I approved in the browser but the app didn't unlock
Switch back to the app manually and tap Link account again. Each attempt issues a fresh token — the old one is harmless if it never made it through.
My test launched but the target is unreachable
Launch failures show up in Panel → Active Tests with a reason. The usual suspects: wrong target, wrong port, or no servers available in your chosen region. Try recording a fresh chain, or open the existing one in the Chain Builder and double-check it.
Still stuck?
Head to Support — include a short description of what you were trying to do and any error the app showed.