Developer Tools

API Substack

Last updated 2026-08-08 · benchmark measured 2026-08-08 — deterministic & reproducible

API tool for posting to Substack from code, the CLI, or AI editors.

Is API Substack production-ready?

Legit.Show scores API Substack 65 out of 100 — the simple average of its 7 measured frames. Legit.Show ran its deterministic 7-Frame production-readiness benchmark on API Substack (public-surface assessment), measured from the public surface with no LLM in the scoring path. Its strongest frame is Reliability; its weakest is Privacy. Every frame it averages is published with its evidence on the Legit.Show listing.

The 7 Frames

• Performance — 92/100
• Accessibility — 92/100
• Security — 25/100
• Privacy — 0/100
• Reliability — 100/100
• Standards — 100/100
• Discoverability — 45/100

What we measured

• No Content-Security-Policy and no HSTS.
• Served over HTTPS with a valid certificate.
• Real Lighthouse performance run — 571 ms to first byte.
• Returns a proper 404 for unknown routes.
• 3 of 3 sampled routes reachable.
• No privacy policy found.
• Sets cookies / loads scripts with no consent prompt.
• Discoverable: sitemap.

Who it's for

Substack writers · Newsletter operators · Content creators · AI tool users

Pricing

7 days free, then $9 per month

Visit API Substack → · Alternatives to API Substack → · How this was measured →