Reaching real people: channel selection, list hygiene and cutting wasted messages.
Deliverability
Free ways to check an e-mail address: syntax, MX lookup with dig or nslookup, disposable and role flags, why SMTP probing backfires, and when to pay.
10 min read
Deliverability
Disconnected phone numbers are reassigned to new people, so every list decays. How recycling works, what the US rules say, and a re-check cadence recipe.
7 min read
Deliverability
How US 10DLC registration works: brands, campaigns, timelines, published fees, throughput, why registered messages still get blocked, and list hygiene.
7 min read
Deliverability
What direct-to-carrier A2P SMS really means, how it differs from aggregator, grey and SIM farm routes, and six tests to check whether your route is direct.
13 min read
Deliverability
Why a number is not SMS-capable (landline, toll-free, VoIP, invalid, opted out), what the API error codes mean, and how to check a number before you send.
14 min read
Deliverability
HLR lookup prices per number and per 1,000: what drives the cost, the pricing models on the market, hidden fees, and how to estimate a list before you pay.
7 min read
Deliverability
Email to SMS gateway list for US carriers in 2026: AT&T ended email to text in June 2025, Verizon calls vtext legacy. Status, sources and what to use instead.
9 min read
Deliverability
How to check if a phone number has been ported: MNP lookup, HLR and carrier lookups compared, what each result field means, and a step-by-step API example.
10 min read
Deliverability
How to check if a number has Viber, where Viber matters most, how checks relate to Viber Business Messages, and a cost model for Viber-first sending.
7 min read
Deliverability
WhatsApp Business API pricing 2026: Meta charges per delivered template by category and country (OTP $0.0008 to $0.0550). October changes, INR deadline.
11 min read
Deliverability
A2P SMS is text messaging sent by software for a business. How it differs from P2P, sender types, what drives cost, deliverability and SMS pumping risk.
8 min read
Deliverability
What an SMS delivery report is, what DELIVRD, UNDELIV, EXPIRED and REJECTD mean, why 'delivered' isn't proof of reading, and why DLRs go missing or wrong.
7 min read
Deliverability
RCS (Rich Communication Services) upgrades SMS in the default messaging app. What the spec covers, RCS vs SMS and chat apps, and how to check who can get it.
7 min read
Deliverability
A simple cost model for pre-send checks: when an HLR, MNP or carrier lookup costs less than the SMS it saves, with formulas and a worked table.
9 min read
Deliverability
WhatsApp, Telegram, Viber, LINE, Zalo, RCS or SMS? How to pick a channel per country for messages customers expect, and measure it on your own base.
7 min read
Deliverability
To test if a number supports RCS, run a capability check: capable, not capable or unknown, before you send. Plus test numbers, iPhone support and SMS fallback.
9 min read
Deliverability
WhatsApp OTP pricing in 2026: Meta charges $0.0008 to $0.0550 per delivered authentication message, by country. Rates vs SMS and a cost-per-user calculator.
9 min read
Deliverability
A step-by-step way to clean a phone list with the MobileValidate jobs API: free estimate, dedupe, invalid rows, capped cost, CSV download and data purge.
8 min read
Deliverability
A delivery receipt reports what happened after you sent an SMS. An HLR lookup asks the network before you send. What each can see, miss and cost.
7 min read
Deliverability
A cause tree for undelivered SMS: invalid numbers, unreachable phones, wrong line types, carrier filtering and handsets, with a fix for each.
7 min read
Create a free account: approved automatically, usually within 10–15 minutes.
Free to start: check 20 phone numbers and 10 e-mail addresses for real on your account, plus an unlimited test mode. You pay only for conclusive answers, from $20.
