Privacy by architecture,
not by policy.

A daily digest of content you care about—with architecture that makes surveillance impossible.

Get Started How It Works

When platforms become informants

These aren't hypotheticals. These are headlines.

NY Times

DHS Wants Social Media Sites to Expose Anti-ICE Accounts

Government ordering platforms to identify users based on political speech

Read Article
The Hacker News

Meta to Shut Down Instagram End-to-End Encrypted Chat

Instagram removing encryption—your DMs become readable

Read Article
Ars Technica

Gmail's 'End-to-End Encryption' Isn't Actually E2EE

Marketing says encrypted, architecture says otherwise

Read Article
The Standard

Meta Scanning Your Phone's Entire Camera Roll

Meta's apps access your entire photo library by default

Read Article
The Edge Singapore

Lawsuit: Meta Can Read WhatsApp Despite E2E Claims

Lawsuit claims Meta can read 'encrypted' messages

Read Article
TechRadar

EU 'Chat Control' Threatens Mass Surveillance of Private Messages

Proposed law would scan all encrypted chats—300+ cryptographers oppose

Read Article

Architecture you can verify

Not promises. Not policies. Cryptographic guarantees.

We can't read your data

  • Your passphrase encrypts everything client-side
  • Server stores only encrypted blobs
  • Even with full database access, we see gibberish
AES-256-GCM, PBKDF2 100k iterations

Sites can't track you

  • Reader mode fetches articles server-side
  • Your IP never touches the publisher
  • Images proxied to prevent fingerprinting
Server-side content extraction

You control the algorithm

  • Your interest model is encrypted—we can't see preferences
  • See exactly why each article was surfaced
  • Adjust weights yourself, not black-box optimization
Encrypted embeddings, transparent scoring

Architecture you can verify

  • Core crypto library is open source on Codeberg
  • No server-side key escrow—keys never leave your device
  • Independent security audits welcome
ECDH P-256, AES-256-GCM, open source
View on Codeberg →

What you control vs. what we see

You Control

  • Your passphrase (never sent to server)
  • Your interest model (encrypted)
  • Your saved articles (encrypted)
  • Who you share with
  • What you share (E2E encrypted)

We See

  • Encrypted blobs we can't decrypt
  • Nothing—it's encrypted
  • Routing metadata only
  • Hashed user IDs
  • Opaque encrypted content
"Even with a court order, we hand over gibberish."

Built for daily reading

Everything you need, nothing you don't.

Daily Digest
  • 15-25 curated articles per day
  • Natural stopping point—no infinite scroll
  • Transparent relevance scores
AI Analysis
  • Thesis extraction
  • Evidence quality assessment
  • Rhetoric detection (fallacies, framing)
Reader Mode
  • Clean, distraction-free reading
  • Server-proxied content
  • Works on paywalled articles
Private Sharing
  • E2E encrypted group chats
  • Threaded comments with reactions
  • Social graph hidden from server
Import Your Data
  • Twitter/X, Reddit, YouTube, bookmarks
  • Jumpstart your interest model
  • All processing encrypted
Multi-Platform
  • PWA: install on any device
  • Offline digest viewing
  • Dark/light theme

How we compare

Feature Penumbra Feedly Flipboard X
E2E Encrypted ✓ — — —
Zero-knowledge server ✓ — — —
No tracking ✓ — — —
Private sharing ✓ — — —
Transparent algorithm ✓ — — —
Ad-free ✓ Paid — Paid

Your browser matters too

Penumbra protects your data within our system. Your browser handles the rest.

Tor Browser
Tracking Strong
Fingerprint Strong
Best for privacy, slower
Mullvad Browser
Tracking Strong
Fingerprint Strong
Tor's tech, normal speed
Brave
Tracking Strong
Fingerprint Moderate
Good default choice
Firefox + uBlock
Tracking Good
Fingerprint Moderate
Solid with extensions
Safari
Tracking Good
Fingerprint Moderate
Decent on Apple
Chrome
Tracking Minimal
Fingerprint Weak
Avoid for privacy

What we can't protect

Honesty about our limits.

When you click external links

You leave our protection. Destination sees your IP and browser fingerprint. Use Reader mode to stay protected.

Passphrase loss = data loss

We cannot recover your data. This is a feature, not a bug. Store your passphrase safely.

Compromised devices

If your device is compromised, all bets are off. Penumbra can't protect against keyloggers.

Ready to read without being read?

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