Swrrl Support · Swrrl

Frequently Asked Questions

What is Swrrl?

Swrrl automatically detects tennis strokes — forehands, backhands, and serves — from a video you already have, and cuts each stroke into its own clip so you can review your technique in detail.

Do I need to create an account to use Swrrl?

No. Swrrl works immediately after install — no sign-up, no login required.

Does Swrrl need access to my camera or photos?

Swrrl doesn't record video itself — you import a video you've already filmed for analysis, which requires no camera or photo permission. The only permission Swrrl ever asks for is Photo Library access, and only when you choose to save a clip back to your camera roll.

Does Swrrl upload my videos to the cloud?

No. All processing happens entirely on your device. Your videos are never uploaded anywhere, and Swrrl doesn't collect or transmit any personal data.

Does Swrrl work without an internet connection?

Yes. Swrrl is fully offline — you can use it right on the court without Wi-Fi or cellular data.

What kind of video works best?

Swrrl analyzes both the player's motion (computer vision) and the sound of ball contact to detect each stroke, so a few things help accuracy:

Keep the player reasonably large and clearly visible in the frame — if they're too far away and appear very small, or are heavily obstructed, detection may suffer
Use a video with its original, unedited audio track — muted videos, audio/video that's out of sync, or contact sounds buried under loud background music can also reduce accuracy

A stable camera angle (e.g. on a tripod) with the player clearly in frame gives the best results.

What strokes does Swrrl detect?

Currently Swrrl detects forehand groundstrokes, backhand groundstrokes, and serves.

Why didn't Swrrl detect one of my strokes, or why did it miss a shot?

This usually comes down to the same two factors Swrrl relies on for detection:

Visual: the player is too far away / too small in frame, or too heavily obstructed
Audio: the video has no original audio, audio and video are out of sync, or the contact sound is hard to hear (e.g. covered by heavy background music)

We're continuing to improve detection accuracy in future updates.

Can I adjust or trim a clip after it's generated?

To keep things simple, Swrrl doesn't support fully freeform trimming. Instead, each clip comes with several built-in size presets — from XS to XL — so you can quickly pick the length that best fits your stroke.

Can I save clips to my Photos app?

Yes. Any clip can be exported and saved directly to your device's Photo Library.

Is there a tutorial or user guide for Swrrl?

Swrrl is designed to be intuitive enough that you shouldn't need one — just open the app and start. That said, we're planning to release short how-to videos in a future update to help you get the most out of it.

What devices does Swrrl support?

Swrrl runs on iPhone and iPad with iOS/iPadOS 26.2 or later.

I found a bug — how do I report it?

Email us at support@beliefcraft.cloud. To help us fix issues faster, please include if you can:

Your device model and iOS version
A short description of what happened vs. what you expected
Steps to reproduce the issue
A screenshot or screen recording, and the original video (if relevant)

We read every message.

I have an idea for a new feature or some UI/UX feedback — can I share it?

Absolutely — we'd love to hear it. Email us at support@beliefcraft.cloud with your suggestions. Swrrl is still early, and we want to build it together with our users to make it better.

Contact Support

Can't find what you're looking for? Reach out and we'll get back to you.

support@beliefcraft.cloud