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Gander, an Android file viewer that asks for no permissions

Hi HN,I built an Android file viewer that opens PDF, Word, Excel, PowerPoint, images, video, audio, Markdown and code, and asks for no permissions at all.I have always been uneasy about opening files people send me. On Android you either install a 400 MB office suite and sign in or use a small free viewer that wants storage access and ends up uploading your file to a server to render it. Also the hassle of having to download different apps for different file formats was really annoying.Gander holds no permissions, not even INTERNET so the OS itself guarantees the file cannot leave the phone.PDFs use Pdfium, media uses Media3, and Office formats are rendered by bundled JS libraries in a WebView and so no request goes to any server.It is a viewer only. Complex PowerPoint decks come out approximately right, spreadsheet charts are not drawn, and old binary .doc and .ppt are unsupported. I'll work on it as issues come up :PIt is 14 MB, MIT licensed and uploaded on Github releases.Do try it! I would love some feedback especially on files that render badly or need new support.

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FL score

72

out of 100

Verdict

VALIDATE

medium confidence

Competition

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Trend

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A lightweight, permission-free file viewer that trades feature completeness for privacy and simplicity.

The pain

Android users face a choice between bloated office suites requiring login, or small viewers that demand storage permissions and upload files to remote servers. Opening files from untrusted sources creates legitimate privacy anxiety. Switching between apps for different file types is friction.

The gap

No existing app combines zero permissions, offline rendering, and multi-format support in a small package. The market has either feature-rich (heavy, permission-hungry) or minimal (limited formats, cloud-dependent) solutions.

Build angle

The creator has built a working product that solves a real problem with a clever technical constraint (no permissions = no data exfiltration). The next phase should validate whether users actually care enough about this specific combination to install and keep the app. Current distribution is GitHub releases only, no app store presence limits reach.

Strengths

  • Solves a genuine privacy concern with technical guarantees rather than promises
  • 14 MB is genuinely lightweight compared to alternatives
  • Multi-format support (8+ formats) in one app reduces friction
  • MIT license and open source builds trust
  • Creator is responsive to feedback and iterating
  • No server dependency means no ongoing infrastructure costs

Risks

  • Feature gaps (no binary Office formats, incomplete chart rendering) may frustrate users expecting full fidelity
  • Zero monetization path identified, unclear if this becomes a business or stays a utility
  • Distribution via GitHub releases only; app store presence would dramatically increase adoption but requires maintenance
  • Market size unknown, how many Android users actually prioritize this specific privacy guarantee over convenience?
  • Competitive pressure from Google's built-in file viewers and Microsoft's lightweight Office apps
  • Maintenance burden grows with format support requests; creator hasn't indicated capacity for scaling

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