--- type: Reference title: "Daniel Mercer — Verification & Deliverability" description: "Daniel focuses on why a verification code arrives, or doesn't. Most of it comes down to one distinction the industry glosses over: real carrier SIMs return \"mobile\" in the line-type checks (Twilio Lookup, Telesign PhoneID) that platforms run before they ever send an OTP, while VoIP numbers come back" resource: "https://virtualsms.io/authors/daniel-mercer" tags: ["author", "daniel-mercer"] updated: "2026-10-05T08:49:42.000Z" generated: at: "2026-10-22T10:51:56.138Z" by: "virtualsms-marketing-site" --- # Daniel Mercer Verification & Deliverability, VirtualSMS 4.9 (on the basis of 541 ratings) [About VirtualSMS](https://virtualsms.io/about) [Help Centre](https://virtualsms.io/help) ## About Daniel Daniel focuses on why a verification code arrives, or doesn't. Most of it comes down to one distinction the industry glosses over: real carrier SIMs return "mobile" in the line-type checks (Twilio Lookup, Telesign PhoneID) that platforms run before they ever send an OTP, while VoIP numbers come back "Non-Fixed VoIP" and get dropped silently. He tracks delivery behaviour across the 2,500+ services VirtualSMS covers, notes when a platform tightens its checks, and writes up what actually changed rather than what a press release claims. When a post here says a number type works on WhatsApp or fails on Binance, it's because the delivery data said so, not because it sounded plausible. **Editorial standards:** All statistics cited in VirtualSMS blog posts link to primary or Tier 1-3 sources. Market figures from generic aggregators are removed or replaced. Product claims reflect real platform behaviour, not marketing copy. See our [About page](https://virtualsms.io/about) for company information. ## Articles by Daniel - 5sim Alternative with Real SIM Cards That Actually Work (2026) Looking for a 5sim alternative with real SIM cards? Real carrier SIMs pass WhatsApp, Telegram, and Google checks that VoIP fails, across 2500+ services. - AgentSIM Alternative: Real-SIM Verification Beyond AI Agents (2026) AgentSIM alternative for real-SIM verification: VirtualSMS uses the same carrier-lookup mechanism, plus a hosted Claude MCP server and REST API. - Best Non-VoIP SMS Verification Services in 2026: Real SIM vs VoIP Compared The best SMS verification services in 2026, tested: VirtualSMS, TextVerified, SMS-Activate, 5sim, SMSPool, OnlineSim. Real SIM vs VoIP compared. - DaisySMS Alternatives in 2026: Best Options After the Shutdown DaisySMS shut down in March 2026. Find the best DaisySMS alternatives with real SIM cards and auto-refunds: SMS-Activate, SMSPool, 5sim, VirtualSMS. - Free SMS Sites vs Paid Virtual Numbers: The Real Cost of Free Free SMS sites vs paid virtual numbers: free costs $0 but exposes your codes in public inboxes and fails on WhatsApp, Telegram, and Google. When each fits. - Free vs Paid SMS Verification: What You Actually Get (2026) Honest comparison of free vs paid SMS verification: why free shared-number sites fail WhatsApp, Telegram, and Google, and when paid real-SIM is needed. - GrizzlySMS Alternatives: Best Options in 2026 Looking for a GrizzlySMS alternative? Compare the best SMS verification services in 2026 with real SIM cards, higher success rates, and auto-refunds. - How Platforms Detect Virtual Phone Numbers in 2026: And Why Real SIM Passes How platforms detect virtual phone numbers in 2026: a 4-layer stack of HLR line type, Line Type Intelligence, MNP flags, and IP fingerprinting. - Mobile Number Portability (MNP): Why It Breaks 8-12% of SMS Verifications in 2026 Mobile Number Portability silently breaks 8-12% of SMS verifications when senders route on the prefix, not the live HLR. Why real-SIM is MNP-immune. - MobileSMS Alternative: Real-SIM Verification That Works (2026) MobileSMS alternative for real-SIM verification: carrier-issued numbers across 2500+ services in 145+ countries, two rental tiers, MCP plus API access. - OnlineSIM Alternative: Real-SIM Numbers, Public Pricing (2026) The best OnlineSIM alternative in 2026 lets you compare SMS verification prices without an account. Real carrier SIM cards, 145+ countries, MCP plus API. - How Much Do Residential Proxies Cost in 2026? We Checked 5 Competitors at Every Volume We captured live pricing from six vendors, VirtualSMS, Decodo, Oxylabs, IPRoyal, Bright Data, VoidMob, at matched volumes. Decodo's marketed $2/GB needs 1,000GB; its real entry price is $3.75. - SMS-Activate Shut Down: 7 Best Alternatives in 2026 SMS-Activate closed in December 2025. Compare the 7 best SMS-Activate alternatives in 2026: real SIM numbers, auto-refunds, and a comparison table. - SMS-Activate Down? Best Working Alternative in 2026 SMS-Activate down or not working? This SMS Activate down alternative offers real carrier-issued SIM activations from $0.05, 2500+ services, 145+ countries. - SMS-Activate vs VirtualSMS: Which Is Better in 2026? SMS-Activate closed in December 2025. This SMS-Activate alternative 2026 guide compares VirtualSMS on real carrier SIM cards, auto-refund, 145+ countries. - How Long Do Verification Codes Take? Real Arrival Times by Platform and Country Measured SMS verification code arrival times across 29,476 orders and 16 platforms. Median and 90th-percentile seconds by platform and by country, with methodology. - UK vs Thailand Virtual Numbers: Which to Use for Verification UK virtual numbers win for global apps like WhatsApp and Google; Thailand numbers win for LINE, Grab, and Lazada. Both real carrier SIMs, compared. - Non-VoIP Numbers for Verification: Real SIM vs VoIP A non-VoIP number for verification passes because real SIM cards return mobile on Twilio and Telesign line checks. VoIP numbers get auto-rejected. - WhatsApp Number Banned? Why It Happens and How to Fix It WhatsApp number banned solutions: WhatsApp bans numbers that fail line-type and behavior checks, most often VoIP. Fix it with a real carrier SIM instead. - Why ChatGPT / OpenAI Rejects Your Phone Number: And the Real Fix (2026) Why ChatGPT rejects your phone number: VoIP detection, unsupported country, recycled-number flag, or carrier-reputation score. The real-SIM fix for each. - Why Your OTP Takes 5 Minutes: The SMS Delivery Stack Explained Why is my OTP taking so long? Your code travels through 6 handoffs before reaching your phone. Per-hop latency, why codes stall, and why real-SIM is fast. - Why SMS Verification Gets Blocked: And How to Fix It Why SMS verification gets blocked: 6 specific reasons, number range blocks, carrier API checks, velocity flags, behavioral signals, delivery analysis. - Why Your Verification Code Did Not Arrive: A Diagnostic Guide Diagnose a verification code that did not arrive by separating documented request, number, account, and delivery restrictions. - Why Your Virtual Number Gets Rejected (And How to Fix It) Why do virtual numbers get rejected for SMS verification? 7 reasons, VoIP detection, number recycling, country mismatch, with a fix for each.