Compress video for Slack
Big videos clog Slack channels and eat into your workspace storage. Slimcast shrinks a clip to a size target you pick, so it posts fast and stays light. It all runs in your browser through ffmpeg.wasm, so your video never leaves your device, nothing uploads, and there's no server to wait on.
Frequently asked
Slack compression, answered
Does my video get uploaded to a server?
No. Slimcast runs entirely in your browser through ffmpeg.wasm. Your video is read, compressed, and saved on your own device. Nothing is uploaded, there's no account, and no waiting on a server. You only share the smaller file in Slack once you're happy with it.
What size should I target for Slack?
Slack doesn't enforce a tiny hard cap, but smaller files post faster and use less workspace storage. Around 25 MB is a good balance of quality and speed for most screen recordings and clips. Pick 10 MB for the quickest share or 50 MB when you want more detail, or type any custom number in MB.
How does Slimcast hit an exact size?
You choose a target in MB and Slimcast measures your clip's duration, then computes the right video bitrate to land the output just under that target. It encodes a web-optimized MP4 (H.264 video, AAC audio, +faststart) using rate control, so you hit the size on the first try without guessing.
Can I compress several videos at once?
Yes. Drag and drop multiple videos and each gets its own queue row with file size, a live progress bar, the output size, and the percentage reduction. You can process them one at a time or all at once, then download each result or grab them all together.