WhatsApp sticker limits: WebP, 100 KB static, 500 KB animated

A WhatsApp Cloud API sticker must be a .webp file: 100 KB at most when static, 500 KB when animated. Sume's images API can return webp through output_format, which covers a static sticker; Sume does not document animated WebP output, so an animated sticker needs a tool outside Sume.

What do the sticker pages say?

Meta's sticker message page lists both types as WebP with those two size caps. It recommends sending by uploaded media id, and says a request fails if the id is invalid or expired, the file is not a supported WebP type, or the file exceeds the size limit. The page does not state pixel dimensions.

How do I make a static sticker?

Ask for a simple subject on a transparent background with background: "transparent" on openai/gpt-image-2.5, and output_format webp. Then measure the file; 100 KB is small, so keep the artwork flat, with few colors and no photographic texture. Sume has no byte-size field, so re-request a simpler image if it is over.

import json, os, urllib.request

body = {
    "model": "openai/gpt-image-2.5",
    "prompt": "flat sticker of a smiling sun, thick outline, no text",
    "aspect_ratio": "1:1",
    "output_format": "webp",
    "background": "transparent"
}
req = urllib.request.Request(
    "https://api.sume.com/v1/images",
    data=json.dumps(body).encode(),
    headers={
        "Authorization": "Bearer " + os.environ["SUME_API_KEY"],
        "Content-Type": "application/json",
    },
    method="POST",
)
print(urllib.request.urlopen(req).read().decode())

What about dimensions?

Because Meta's page here gives none, look at WhatsApp's sticker guidance for the recommended size and compare it with what Sume returns.

What should I verify?

Send a test sticker to your own number. The images guide lists the parameters.