The Strict Wix File Upload Ceiling

Native Wix Forms impose restrictive file size limits:

Standard Wix forms cap single uploads between 10MB and 25MB.

Certain high-resolution file formats (.raw, .ai, .psd, .mp4, .zip) are either throttled or blocked by server mime-type firewalls.

Media uploaded natively clutters the Wix Media Manager without structured client folder hierarchies.

For design agencies, architectural studios, video production houses, and legal firms collecting heavy case bundles, this restriction is a deal-breaker.

Why Direct S3 Pre-Signed Uploads Win

Pushing heavy binaries through your web application server causes timeouts and memory spikes. The modern cloud approach uses Pre-Signed URLs:

1The client browser asks FormWix for a short-lived cryptographically signed AWS S3 upload token.

2The user's browser transmits file attachments up to 10MB over secure TLS.

3Once completed, FormWix records the authenticated S3 file URL and dispatches the metadata to your CRM or email notification.

Your Wix site stays lightning fast, and client upload speeds are maximized by AWS global edge locations.

Step 1: Link AWS S3 in FormWix

1In FormWix Dashboard, open Connectors → AWS S3.

2Provide your AWS Access Key ID, Secret Key, Bucket Name, and Region (e.g. us-east-1).

3Set your dynamic folder prefix rule (e.g. wix-uploads/{year}/{form_id}/).

4All uploaded attachments are securely stored with private access control.

Step 2: Native Wix Studio Velo Code

Use this streamlined Velo snippet to request the pre-signed URL and upload large files with a progress bar:

javascriptWix Studio Snippet

import { fetch } from 'wix-fetch';

async function handleLargeFileUpload(file) {
  // 1. Get signed upload URL from FormWix
  const tokenRes = await fetch('https://formwix.com/api/v1/upload-url', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      filename: file.name,
      contentType: file.type,
      formId: 'YOUR_FORM_ID'
    })
  });
  
  const { uploadUrl, filePublicUrl } = await tokenRes.json();

  // 2. Direct binary PUT to S3
  await fetch(uploadUrl, {
    method: 'PUT',
    headers: { 'Content-Type': file.type },
    body: file
  });

  return filePublicUrl;
}

Security & Bucket Policies

Zero Public Bucket Exposures: Keep your S3 bucket private. FormWix generates time-limited signed download links when dispatching email alerts.

Client Isolation: Each client submission receives a unique UUID folder prefix, preventing filename collisions and unauthorized directory traversal.

Written by Dong Trinh

Lead Architect at FormWix. Passionate about high-performance visual web engineering, frictionless developer APIs, and building headless form infrastructure for modern agencies.

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Wix Forms File Upload Limits & How to Handle Secure Form Attachments