What sticker files actually are
Messaging apps use several formats under the “sticker” label. Telegram animated stickers (.tgs) are gzip-compressed Lottie JSON — vector animations limited to 512×512 px and 3 seconds. Telegram video stickers are 512 px WebM files using the VP9 codec, which supports transparency. WhatsApp stickers are 512×512 WebP images, animated or still. Each needs a different decoder; this tool picks the right one automatically.
Because GIF supports only fully transparent or fully opaque pixels, the soft edges of stickers can look slightly jagged over dark backgrounds. If you know where the GIF will be shown, choose a matching background colour for the cleanest edge.
Related conversions
For Lottie files from designers (JSON or .lottie), Lottie to GIF offers frame-rate control. Animated AVIF images go through AVIF to GIF. To make your own stickers, start with a GIF and remove its background, then resize to 512×512.