Sources & Methodology
How this guide is researched, fact-checked, and kept current — and the primary sources behind it.
How this guide is built
Every page was researched across primary sources (The Campaign Registry, the FCC, CTIA, Somos), the major CPaaS documentation (Twilio, Telnyx, Bandwidth), and legal analysis, then each key claim was independently fact-checked before publishing. Where a figure couldn’t be pinned to an authoritative source, we say so.
Freshness policy
Fees, throughput tiers, and regulatory dates change on published schedules. So:
- Every volatile number lives in a single shared data file, and every page that shows it carries a “Last verified” date.
- Figures we expect to change carry a Verify live as of mid-2026 marker — re-check the primary source before relying on them.
- The change tracker is updated as rules move.
Not legal advice
This site is informational. It is not legal advice. Verify fees, deadlines, and compliance requirements with your CSP, carrier, or counsel before relying on them.
Primary sources
- The Campaign Registry — Fees & Pricing
- FCC — Call Authentication / STIR-SHAKEN
- FCC — Robocall Mitigation Database
- CTIA — Messaging Principles & Best Practices
- Somos — U.S. Short Code Registry
- FreeCallerRegistry.com
A full, per-topic source list appears at the bottom of each reference page.