Sending images, documents and voice notes that actually arrive
WhatsApp accepts images, documents, audio and video with different limits for each, and one trap that costs everybody an afternoon: WebP is the sticker format. A logo saved as WebP will not display as an image, and the failure is quiet.
The limits worth knowing
| Type | Formats | Size |
|---|---|---|
| Image | JPEG, PNG | About 5 MB |
| Sticker | WebP | Small, and this is what WebP means here |
| Document | PDF, Office formats, plain text and most others | Up to 100 MB |
| Audio | AAC, MP3, AMR, OGG with Opus | About 16 MB |
| Video | MP4, 3GP, H.264 with AAC | About 16 MB |
The WebP trap. Modern image pipelines convert to WebP by default because it is smaller, and every browser handles it. Send that file to WhatsApp as an image and you get a sticker, an error, or nothing - depending on the path. If your logo lives in a CDN that serves WebP by content negotiation, you can pass a URL ending in .png and still receive WebP bytes. Check the bytes, not the extension.
Captions, and where they are ignored
Images, videos and documents take a caption. Audio does not - send a voice note and any accompanying text has to be its own message. Software that assumes a caption always works will silently drop text on audio sends, and nobody notices because the audio arrives.
Documents: name the file
A document arrives with a filename, and if you do not set one the recipient gets something like a4f9c2.pdf. Set it to what a person would call it - Invoice-10432.pdf - because that string is what they will search their phone for in three months.
Voice notes are not audio files
A voice note renders as the waveform with a play button; an audio file renders as an attachment. Same bytes, different flag. If you are sending something recorded by a person, send it as a voice note - it gets listened to far more often.
Practical advice
- Compress before sending. A 4 MB product photo and a 400 KB one look the same on a phone. The second arrives on a slow connection.
- Convert deliberately. Do not rely on whatever your CDN negotiates. Convert to JPEG or PNG at the point of sending and verify the magic bytes.
- Do not send a 100 MB document because you can. The recipient pays for the data.
- Handle inbound media too. Customers send photos of broken parts and screenshots of payments; those are often the most important messages in the conversation, and an inbox that shows them as "[image]" is not doing its job.
- Mind retention. Media hosted by the platform expires. If a photograph is evidence, store your own copy.
Questions people actually ask
Why does my WebP image not send on WhatsApp?
WhatsApp treats WebP as the sticker format. A logo saved as WebP is not an image WhatsApp will display as one - convert to PNG or JPEG before sending.
What is the maximum file size on WhatsApp?
Documents up to 100 MB, images around 5 MB, and audio and video around 16 MB on the Cloud API. Practical limits are lower: recipients on slow connections will not download a 90 MB PDF.
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