FAQ - Frequently Asked Questions

Common questions about PreviewFile.dev features, pricing, security, and technical implementation.

PreviewFile.dev is a secure file preview service that generates short-lived, customizable preview links for 110+ file formats. Share PDFs, Office documents, images, videos, and more without exposing original URLs or requiring downloads.

→ Learn more in Getting Started

Which file formats are supported?

We support 110+ formats including:

Documents: PDF, DOCX, PPTX, XLSX, TXT, MD
Images: JPG, PNG, GIF, WebP, SVG, TIFF
Videos: MP4, WebM, MOV, AVI
Code: JS, Python, Java, Go, and 50+ languages
Archives: ZIP, RAR, 7z, TAR

→ See complete list in Supported Formats

How does the pricing work?

Free: 100 previews/month, 15-minute TTL
Pro: 10,000 previews/month, custom watermarks, 24-hour TTL
Team: 100,000 previews/month, white-label, SSO
Enterprise: Unlimited, SLA, dedicated support

→ Compare plans in Pricing

Technical Questions

How do I generate a preview link?

Use the REST API to create preview links programmatically:

curl -X POST https://previewfile.dev/api/u \
  -H "x-api-key: $API_KEY" \
  -d '{"url": "https://example.com/file.pdf", "ttlMinutes": 60}'

→ Full guide in API Documentation

Do you store my files?

No. We only cache metadata and thumbnails.

→ Read about our architecture in Security Policies

Can I use this for sensitive documents?

Yes. Enable these security features:

Time-limited links: Auto-expire after 5 minutes to 24 hours
Watermarks: Add custom text overlays
No-download mode: Prevent file downloads
One-time links: Expire after first access

→ Explore all options in Security Policies

What happens when a link expires?

Expired links show a "Link Expired" error page. The preview metadata is automatically deleted from our database, and any cached thumbnails are purged within 1 hour.

Can I embed previews in my app?

Yes. Use <iframe> with the preview URL:

<iframe src="https://previewfile.dev/p/abc123" 
        width="100%" height="600px"></iframe>

Team plans support domain whitelisting to restrict where embeds work.

→ API details in API Documentation

Security Questions

Is my original URL exposed?

No. Recipients only see the short preview URL (e.g., previewfile.dev/p/abc123). The original file URL is never visible in the browser or network logs.

How do watermarks work?

Watermarks are rendered client-side using Canvas/GPU overlays. You can customize text, positioning, and opacity. Team plans support custom fonts and logos.

→ Configuration guide in Security Policies

Can I restrict access by IP or referrer?

Yes (Team+ plans). Configure:

IP whitelisting: Only allow specific IPs
Referrer restrictions: Block hotlinking
User-Agent validation: Prevent automated scraping

→ Advanced controls in Security Policies

Are you GDPR/HIPAA compliant?

Enterprise plans include:

Data processing agreements (DPA)
Audit logs for all access events
Regional data residency options
SOC 2 Type II certification

Contact sales for compliance documentation.

Product Questions

What's the difference between Free and Pro?

Feature	Free	Pro
Monthly previews	100	10,000
Max TTL	15 minutes	24 hours
Custom watermarks	❌	✅
Download control	✅	✅
One-time links	✅	✅

→ Full comparison in Pricing

Can I white-label the preview pages?

Yes (Team+ plans). Customize:

Custom domain (preview.yourdomain.com)
Branded header/footer
Custom CSS themes
Remove "Powered by PreviewFile" footer

Contact sales for white-label setup.

Do you offer API rate limiting?

Yes. Rate limits by plan:

Free: 100 requests/hour
Pro: 1,000 requests/hour
Team: 10,000 requests/hour
Enterprise: Custom limits

Exceeded limits return HTTP 429 with Retry-After header.

→ API reference in API Documentation

Can I get usage analytics?

Yes. Dashboard shows:

Total previews generated
Most viewed files
Geographic distribution
Format breakdown
Expiration patterns

Team plans include CSV export and webhook notifications.

Integration Questions

Which languages do you support?

We provide examples for:

JavaScript/Node.js, Python, Java, C#, Go
Rust, PHP, Ruby, Swift, Kotlin

→ Code samples in API Documentation

Can I use this with AWS S3 / Google Cloud?

Yes. Generate signed URLs from your storage provider, then pass them to PreviewFile:

const s3Url = await getSignedUrl(s3Client, getObjectCommand);
const preview = await fetch('/api/u', {
  body: JSON.stringify({ url: s3Url })
});

Ensure signed URLs are valid for longer than your preview TTL.

Do you have SDKs?

Official SDKs coming soon. Currently use standard HTTP clients with the REST API.

→ Request SDK in GitHub Discussions

Can I self-host this?

Enterprise plans include on-premise deployment options with Docker/Kubernetes manifests. Contact sales for licensing.

Troubleshooting

Why is my preview showing "Unsupported Format"?

Verify file extension matches MIME type
Check if format is in Supported Formats
Ensure origin URL is publicly accessible
Try re-uploading with correct MIME type

Preview link returns 404

Common causes:

Link expired (check expireAt timestamp)
One-time link already accessed
Invalid short URL (check for typos)

Video/audio preview not working

Ensure:

File is in supported codec (H.264/AAC recommended)
Origin server sends correct Content-Type header
CORS headers allow cross-origin access
File size < 500 MB for optimal performance

→ Report issues in GitHub Issues

Credit/debit cards (Visa, Mastercard, Amex)
PayPal (Team+ plans)
Invoice/ACH (Enterprise only)

Do you offer discounts for nonprofits?

Yes. Nonprofits and educational institutions get 50% off Pro/Team plans. Contact sales with proof of status.

Still have questions?

📧 Email: [email protected]
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🐦 Twitter: @previewfile
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