Comparison

No-upload file converters

A no-upload converter should make its processing model testable. For supported ConvertUnlimited workflows, selected file contents are processed locally in the browser and the privacy build uses same-origin runtime assets without third-party runtime scripts.

Short answer

Do not trust a no-upload claim by wording alone. Check where processing happens, whether an upload endpoint is used, whether third-party scripts run, and whether the behavior can be verified in DevTools.

Privacy behavior

For supported ConvertUnlimited tools, selected file contents are processed locally in your browser. The public site may load ads and analytics; use the privacy build for privacy-sensitive workflows.

Best next step

Choose the related tool below that matches your file type and output goal, then review the limitations before processing large or sensitive files.

What no-upload should mean

A useful no-upload claim should be scoped to a specific processing flow, not the entire website. It should explain that the selected file is read and transformed locally in the browser for supported tools.

The claim should also be testable. Network inspection should not show file-content upload requests during the processing step.

Claim checklist

Question	Why it matters	ConvertUnlimited privacy build
Is the tool browser-native?	Local APIs reduce the need for upload	Yes for supported workflows
Are ads or analytics loaded?	Third parties can observe page activity	No in the privacy build
Are runtime libraries same-origin?	CDNs are executable dependencies	Vendored where needed
Is connect-src restricted?	Limits network APIs in supporting browsers	connect-src 'none'
Can users verify behavior?	Trust should be inspectable	DevTools and repository tests

Verification steps

Open a clean browser profile, visit the privacy build, open DevTools Network, disable cache, process a small sample file, and review new requests.

Expected activity should be same-origin static assets or local browser URLs such as blob: and data:. Unexpected upload, measurement, monetization, CDN, or beacon requests should be investigated.

Limitations

No-upload does not mean no network requests before the page is loaded.
No-upload does not protect against compromised browsers, extensions, operating systems, or host-level script injection.
Some formats and files still require cloud or desktop tools.

Related trust pages and guides

FAQ

How can I tell whether a converter uploads files?

Inspect the Network panel while processing a sample file and look for upload or third-party requests.

Does no-upload mean the site has no third parties?

No. A site can process files locally while still loading third-party measurement or monetization scripts. Use the privacy build when that distinction matters.

Does ConvertUnlimited provide a server-side upload endpoint for supported local flows?

No. Supported local-processing flows use browser APIs and client-side code rather than a ConvertUnlimited upload endpoint.

Action

Start with Image Converter, then use the linked guides to verify behavior and choose the right format.

Review note

Comparison criteria reviewed: May 2026.