Productivity

Letterboxx

Last updated 2026-07-21 · benchmark measured 2026-09-16 — deterministic & reproducible

Letterboxx is a Mac app for reading and organizing email newsletters.

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To cite this score: legit.show/s/letterboxx-app/2026-09-16. That address never changes; this page moves with every re-measure.

Legit.Show scored Letterboxx 95/100 on 2026-09-16, measured across all 7 frames from its public surface. legit.show/s/letterboxx-app/2026-09-16

Is Letterboxx production-ready?

Legit.Show scores Letterboxx 95 out of 100 — the simple average of its 7 measured frames. Legit.Show ran its deterministic 7-Frame production-readiness benchmark on Letterboxx (public-surface assessment), measured from the public surface with no LLM in the scoring path. Its strongest frame is Security; its weakest is Performance. Every frame it averages is published with its evidence on the Legit.Show listing.

The 7 Frames

• Performance — 79/100
• Accessibility — 93/100
• Security — 100/100
  How this compares across the catalogue: The Web Security Baseline
• Privacy — 100/100
  How this compares across the catalogue: The Privacy Gap
• Reliability — 100/100
• Standards — 92/100
• Discoverability — 100/100

What we measured

• Security headers present: CSP, HSTS, X-Frame-Options, X-Content-Type-Options, Referrer-Policy.
• Served over HTTPS with a valid certificate.
• Real Lighthouse performance run — 191 ms to first byte.
• Returns a proper 404 for unknown routes.
• 3 of 3 sampled routes reachable.
• Has a reachable privacy policy.
• Sets cookies / loads scripts with no consent prompt.
• Discoverable: structured data, sitemap, OpenGraph image, canonical URL.

Who it's for

Newsletter subscribers · Mac users · Information readers · Research enthusiasts

Pricing

Monthly $4.99/month or Annual $39.99/year (save 33%); 14 days free trial

Sources and updates

Description

Taken from letterboxx.app's own website on 2026-07-21.

Benchmark

Measured by Legit.Show from the live site, the way any visitor sees it — with no access to its code or accounts. Same method for every product, and no AI decides the score. Last checked 2026-09-16.

Put together from public information, without Letterboxx's involvement. If anything here is wrong, tell us and a person will check it.

Visit Letterboxx → · Alternatives to Letterboxx → · How this was measured →