Quick Facts

• Dial: +1 MCCs: multiple (AT&T, T-Mobile, Verizon, etc.).
• Sender types for OTP: 10DLC local numbers, Toll-Free (8xx), Short Codes. Alphanumeric Sender ID is not supported in the US/CA.

What works best for OTP in the US

• 10DLC (local 10-digit numbers) — Mandatory brand + campaign registration via The Campaign Registry (TCR); 2FA/OTP is a standard campaign use case. Unregistered traffic is broadly blocked as of 2024/2025 enforcement. Throughput depends on brand/campaign vetting & trust scores. 
• Toll-Free — Verification is required for US/CA; unverified TFN traffic is blocked. Suitable for OTP & customer care. 
• Short Code (5–6 digits) — Highest throughput/reliability; needs full CTIA/carrier approval and weeks of lead time. Best for very high-scale OTP.
• Alphanumeric Sender ID — Not available in the US/CA (use 10DLC/Toll-Free/Short Code instead).

Compliance & content rules you must meet (even for OTP)

• Opt-in/consent & disclosures (STOP/HELP, message frequency, T&C/Privacy URL) per CTIA Messaging Principles and short-code standards. OTP generally qualifies as transactional user-initiated traffic, but your campaign still needs compliant flows.
• Prohibited content (SHAFT, illegal/illicit) and carrier code-of-conduct violations can trigger fines/blocks (e.g., T-Mobile enforcement).

“Receiving a code” to US numbers — what to expect

• Some apps block VoIP/virtual numbers for account verification (security/anti-abuse). This is common with major platforms; policies vary by app.
• Short code originators: delivery to virtual numbers depends on the provider; premium short codes are often unsupported. Check compatibility per app and number type.

PingMe products mapped to US OTP scenarios

• PingMe US numbers to receive OTP — “Second phone number” / “Receive SMS Online (USA)” pages list rotating US numbers to capture verification codes (temporary or disposable usage). Ideal when you need a one-off code to a US route.
• PingMe Verification Code Helper API — Programmatic access to get numbers and fetch inbound codes; useful for integrating OTP reception into your workflow/tools. 
• PingMe “SMS Verification Code Helper” — Cataloged app targets & guidance on receiving verification messages (platform acceptance still depends on each app’s policy).
• Heads-up: If a target app blocks VoIP/virtual numbers, delivery can fail regardless of number freshness. Always test the specific app + number type before relying on it in production flows.

Registration & KYC at a glance (sending OTP to US users)

• 10DLC: Register Brand (EIN/Tax ID) + Campaign (use case “2FA/OTP”) in TCR; messages from unregistered 10DLC are filtered/blocked.
• Toll-Free: Submit Toll-Free Verification before sending; unverified traffic is blocked in US/CA.
• Short Code: Apply & pass CTIA/carrier vetting; expect weeks from submission to live.

Throughput & deliverability (sending)

• Throughput on 10DLC is assigned per brand/campaign/trust score; 2FA/OTP is a recognized campaign type. Registration generally reduces filtering and improves MPS.
• Toll-Free delivers well for OTP once verified; Short Codes deliver the highest scale/priority when you need massive volumes.

Common failure cases & fixes

• Unregistered 10DLC traffic blocked → Complete TCR brand + campaign; choose 2FA/OTP use case; ensure opt-in evidence.
• Toll-Free blocked → Submit Toll-Free Verification; wait for approval before load. 
• Codes don’t arrive to a VoIP/virtual number → The app may disallow VoIP. Try a different route/number type or a SIM-based destination that app accepts.
• Content/flow non-compliant → Add STOP/HELP handling, clear disclosures, and avoid prohibited content.

Fast implementation checklist

If you need to receive OTP to a US number (research/testing, privacy use-cases):

• • Grab a US number from PingMe (manual or API) → trigger verification → read inbound code. Note app policies may block VoIP.

If you need to send OTP to US users (your own customers):

• • Pick a sender: 10DLC (most common), Toll-Free (verified), or Short Code (at scale).
  • Register (10DLC: Brand+Campaign “2FA/OTP”; Toll-Free: Verification).
  • Implement CTIA-compliant consent & keyword handling (STOP/HELP).

Source

• TCR (identity/registration rules). 
• Twilio A2P 10DLC overview, campaign types, throughput, & approval requirements. 
• CTIA Messaging Principles (2023) & Short Code Handbook (2024). 
• Toll-Free verification (US/CA) — required; unverified blocked.
• Alphanumeric Sender ID not supported in US/CA.
• VoIP/virtual number acceptance varies by app (examples: WhatsApp restrictions; Riot’s SMS policy; general VoIP caveats).
• PingMe product pages & API docs (US numbers to receive OTP; Verification Code Helper API).