Media Library

The Media tab in the dashboard is where you upload the images, videos, audio and documents your survey sends to respondents. You upload a file, you copy the URL it gives you back, and you paste that URL into your survey. That is the whole feature.

The URLs it produces work on every platform Fly supports — WhatsApp, Messenger and Instagram — with no per-platform setup and no per-platform copy of the file.

1. Open Media in the dashboard navigation.
2. Drag a file onto the upload box (or click it to pick one).
3. The file appears in the list below with a URL next to it. Click the URL to copy it.
4. Paste that URL into the url field of an attachment question. See Question Types for the JSON.

The URL looks like this:

https://media.vlab.digital/a/550e8400-e29b-41d4-a716-446655440000/welcome.png

You do not need a connected Facebook page or WhatsApp number to upload. You can build your whole survey’s media library before you connect any account at all.

If you upload the same file twice, you get the same entry back rather than a duplicate — the library tells you it was already there and shows you its existing URL.

A file is accepted only if it is one of the formats below. Limits are the strictest of any platform we send on, so anything the library accepts is guaranteed to send on WhatsApp, Messenger and Instagram alike.

Some formats you might expect are deliberately not accepted:

• GIF and WebP images — not supported across all the messaging platforms we send on. Convert to PNG or JPEG, or to MP4 for an animation.
• Plain text files (.txt), .doc, .xls, .ppt — send a PDF or the modern Office format (.docx, .xlsx, .pptx) instead.

We never resize, transcode or convert your files. If a file is refused, the error tells you exactly why — fix the file and upload it again.

We check what a file actually is, not what it is named. Renaming a .gif to .png will not get it accepted, and a correctly-formatted file with a missing or wrong extension will still be accepted for what it is.

Anyone with the link can open the file, forever. These URLs are not listed anywhere and cannot be guessed, but they are not password-protected: anyone you send one to — or anyone it is forwarded to — can open the file, indefinitely.

Do not upload anything confidential. Media meant for respondents to receive is exactly the right thing to put here.

There is also no delete button. A survey can reference an asset by URL, and deleting the file would silently break every live survey pointing at it. If you need something removed, contact us and we will handle it.

The filename is part of the URL, and on WhatsApp it is what the respondent sees when a document arrives. Upload consent-form-2026.pdf and that is the name in their chat; upload final_v3_FINAL.pdf and that is what they get.

Name documents the way you want respondents to read them, before you upload.

For images, video and audio the filename is cosmetic.

You can still point an attachment question at any public URL you control instead of uploading:

{"type": "attachment",
 "keepMoving": true,
 "attachment": {
    "type": "image",
    "url": "https://example.org/my-image.png"
 }
}

That works, with three conditions you own rather than us:

• It must be HTTPS and publicly reachable — no login, no IP allowlist.
• It must stay reachable for the life of the survey. If it moves or 404s, respondents get nothing.
• It must be within the format and size limits above, which we cannot check for you in advance — a file that is too large fails at send time, per respondent, rather than at upload time, once.

Media uploaded to the library avoids all three problems, and sends measurably faster (see below). Prefer it.

You do not need to know any of this to use the feature — it is here so the behaviour is not mysterious.

When you upload a file, Fly stores it and then, in the background, pre-uploads a copy to every messaging account you have connected — each WhatsApp number, each Facebook page. When your survey sends that media, we send the pre-uploaded copy by reference rather than making the platform fetch your URL, which is faster and far less likely to fail.

Consequences worth knowing:

• You never configure this. There is no platform selector and no per-account upload step. Connect an account later and the pre-uploads happen on their own, usually within the hour.
• It cannot break your survey. If a pre-upload has not happened yet, or has expired, or fails outright, we fall back to sending your URL. The message still goes out.
• The same JSON works everywhere. One url in your survey covers every platform and every account.

If you have used attachment_id before: that was the old way of referencing a file pre-uploaded to a specific Facebook page. It still works on Messenger for surveys that already use it, but it does nothing on WhatsApp and should not be used in new surveys. Upload the file to the Media library and use its URL instead — you get the same speed benefit, on every platform, with no manual step.