File Viewer

Free plan Self-hostedWeb

What File Viewer is

File Viewer is a browser-based component ecosystem for previewing business files. It parses and renders files in the browser rather than using a conversion server, and runtime assets can be hosted on a customer's own origin for offline or private deployments. The project lists 274 registered extensions across 47 preview pipelines, with 224 stable and 50 experimental. Viewer options include search, zoom, print, download, HTML export, watermarks, lifecycle hooks and operation guards.

Integration packages are listed for Vanilla JavaScript and Web Components, Vue 2 and 3, React, Svelte and jQuery. Teams can install individual renderers or choose bundles for text and media, Office documents, engineering formats or the full published matrix. A file URL must be reachable by the browser; cross-origin files need suitable CORS headers, and a File object can also be supplied. The project says its own source and packages use Apache-2.0, while optional dependencies retain their own licenses. File Viewer is a viewer, not an editor, and does not promise native-app fidelity for every complex file. Large files, fonts, vendor-specific features and encrypted files can affect performance or fidelity.

Who it suits

File Viewer suits development teams building browser-based file previews into web applications. Its self-hostable runtime and framework integrations may fit private or offline deployments.

What it does well

Parses and renders files in the browser
Lists 274 extensions across 47 pipelines
Integrations cover popular JavaScript frameworks
Runtime assets can be hosted on your own origin
Viewer includes search, print and HTML export

What to know first

It is a viewer rather than an editor
Complex files may not match native-app fidelity
Large files can affect performance and memory
Cross-origin URLs need appropriate CORS headers

Limits

File Viewer is read-only and does not promise native-app fidelity for every complex file. Very large inputs can affect performance and memory use; fonts, vendor-specific features, and encrypted files can also affect fidelity or memory use.

Getting started

Visit https://file-viewer.app/ and choose a distribution route such as npm, a public GitHub repository, or release downloads.
Select individual renderers or a Lite, Office, Engineering, or Full preset.
Use an integration package for your framework or JavaScript setup.
Provide a browser-reachable file URL or a File object; configure CORS for cross-origin URLs.
For offline or private deployments, serve runtime assets from your application's own origin.

Verdict

File Viewer offers broad preview coverage and multiple integration options, including self-hosted deployment. It is read-only, and teams should validate complex or very large files against their needs.

Questions

Is File Viewer free?

Its pricing model is free, and the maker describes it as open source.

What license does it use?

File Viewer-owned source and packages use Apache-2.0. Optional external dependencies retain their own licenses.

Which platforms and frameworks does it support?

The listed platforms are web and self-hosted. Integration packages cover Vanilla JavaScript and Web Components, Vue 2 and 3, React, Svelte, and jQuery.

Can it preview Office, code, and archive files?

The listed capabilities include Office file preview, code file preview, and archive preview.

Does it work offline?

Runtime assets can be served from the application's own origin for offline deployments.

Does File Viewer edit files?

No. The maker describes it as a viewer rather than an editor.

Facts from File Viewer's own pages

Commercial offering: A separate commercial Office engine focuses on Word, Excel, and PowerPoint fidelity, large-file performance, private delivery, and enterprise support. · file-viewer.app, 1 Oct 2026
Distribution: The project is distributed through npm packages, public GitHub repositories, release downloads, and self-hostable runtime assets. · doc.file-viewer.app, 1 Oct 2026
Features: Viewer options include search, zoom, print, download, HTML export, watermarks, lifecycle hooks, and operation guards. · doc.file-viewer.app, 1 Oct 2026
Format coverage: The product site reports 274 registered extensions and 47 preview pipelines, with 224 stable and 50 experimental. · file-viewer.app, 2 Oct 2026
Formats: The maker lists 274 registered file extensions across 47 preview pipelines, with 224 stable and 50 experimental extensions. · file-viewer.app, 1 Oct 2026
Frameworks: Integration packages are listed for Vanilla JS/Web Components, Vue 2 and 3, React, Svelte, and jQuery. · github.com, 2 Oct 2026
Input requirements: A file URL must be reachable by the browser, and cross-origin files need appropriate CORS headers; a File object can also be supplied. · github.com, 2 Oct 2026
Integrations: The maker documents integrations for Vanilla JavaScript and Web Components, Vue, React, Svelte, and jQuery. · doc.file-viewer.app, 1 Oct 2026
Known constraints: The project says fonts, vendor-specific features, encrypted files, and very large inputs can affect fidelity or memory use. · github.com, 2 Oct 2026
Large files: The maker advises validating extreme large files with real samples because file size can affect performance and memory use. · doc.file-viewer.app, 1 Oct 2026
License: The source is licensed Apache-2.0, while the DWG/DWF/DWFX runtime packages named by the project are AGPL-3.0-only. · github.com, 2 Oct 2026
Limit: File Viewer is a preview component rather than a professional editor and does not promise native-app fidelity for every complex file. · doc.file-viewer.app, 1 Oct 2026
Modular packages: Teams can install individual renderers or choose Lite, Office, Engineering, or Full presets. · doc.file-viewer.app, 2 Oct 2026
Offline deployment: The documentation says runtime assets can be served from the application's own origin for offline or private deployments. · doc.file-viewer.app, 2 Oct 2026
Presets: Preset bundles cover lightweight text and media, Office documents, engineering formats, or the full published matrix. · doc.file-viewer.app, 1 Oct 2026
Product: File Viewer is a read-only, browser-based file preview component for Office, PDF/OFD, CAD, archives, email, and other formats. · github.com, 2 Oct 2026
Read-only: The project describes File Viewer as a viewer rather than an editor. · github.com, 2 Oct 2026
Rendering: Built-in renderers do not require a conversion server; Workers, WASM, and fonts can be self-hosted. · github.com, 2 Oct 2026
Security and privacy: The maker describes the product as browser-local and self-hostable, allowing files and runtime assets to stay within the deployment environment. · doc.file-viewer.app, 1 Oct 2026
Support: The repository directs users to GitHub Sponsors for maintenance support and enterprise support for private deployments or response commitments. · github.com, 2 Oct 2026

Where File Viewer stands on Freedom251

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