Guides and research on phone-number verification, fraud prevention and deliverability from the MobileValidate team.
Guides
Check an Indian list for WhatsApp: turn 0, 91, 091 and Hindi-digit cells into +91, keep 6–9 mobiles, get a free estimate, and follow DPDP Act and TRAI rules.
16 min read
Guides
Check a Nigerian list for WhatsApp: turn 080, 081, 070, 090 and 091 numbers into +234, fix 00234 cells, get a free estimate, and follow NCC and NDPA rules.
15 min read
Guides
Check a Philippine customer list for WhatsApp and Viber: turn 09XX into +63 9XX, keep the 08 mobile blocks, get a free estimate, follow the Data Privacy Act.
17 min read
Guides
Check a Vietnamese list for WhatsApp and Zalo: convert old 11-digit 01X numbers, turn 09X into +84 9X, get a free estimate and follow the 2026 data law.
17 min read
Guides
Cambodia phone number format: +855 and 8- or 9-digit mobiles, TRC prefixes for Cellcard, Smart, Metfone and Seatel, tested code, SIM rules and Telegram checks.
19 min read
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
Guides
Kuwait phone number format: +965 plus 8 digits, mobiles on 41, 5, 6 and 9, tested code for library gaps, porting since 2013 and the new 2025 MNP rules.
21 min read
Guides
Qatar phone number format: +974 plus 8 digits, mobiles on 3, 5, 6 and 7, tested validation code, porting since 2013, sender rules and PDPPL consent.
21 min read
Guides
Tanzania phone number format: +255 and 9-digit 06/07 mobiles, TCRA operator prefixes (Vodacom, Yas, Airtel, Halotel, TTCL), tested code, porting and SMS rules.
20 min read
Developers
Fictional phone number ranges that regulators reserve in the UK, US, Canada, Australia, Germany and France, how libphonenumber treats them, and safe OTP tests.
11 min read
Guides
Check a Bangladeshi customer list for WhatsApp: turn 01X, +88 0 and Bengali-digit cells into +880, dedupe, get a free estimate, and follow the 2026 data law.
13 min read
Guides
Check a Malaysian customer list for WhatsApp: fix 01X, 011 and 60 formats to +60, dedupe, get a free estimate, and follow the PDPA 2010 and its 2024 amendments.
13 min read
Guides
Check a Mexican customer list for WhatsApp: drop the old +52 1, set the country, dedupe, plan for the 2026 line registry, and follow the new 2025 LFPDPPP.
14 min read
Guides
Check a Pakistani customer list for WhatsApp: turn 03XX, 92 and 3XX cells into +92, drop dead 03 blocks, get a free estimate, and follow PTA and PECA rules.
14 min read
Guides
Dutch phone number format: +31 plus 9 digits, 06 mobiles, 0970 M2M numbers, tested validation code, 1-day porting, opt-in sales calls and SMS consent.
19 min read
Research
WhatsApp authentication rates for 44 markets (Meta, October 2026), why SMS OTP prices differ by country, and when a number check costs less than a wasted code.
14 min read
Guides
Polish phone number format: +48 plus 9 digits, no trunk 0, 13 mobile prefixes, tested validation code, 1-day porting, anti-spoofing law and SMS consent.
19 min read
Fraud prevention
For number providers, MVNOs and virtual-number resellers: quarantine rules by country, the FCC database, and HLR and app-account checks before reissue.
12 min read
Guides
Taiwan phone number format: +886 and 10-digit 09 mobiles, area codes, 0800 and 070 ranges, tested code, porting since 2005 and the anti-fraud SMS rules.
24 min read
Guides
Eight phone validation and lookup APIs compared on public, dated evidence: data fields, price at 10,000 lookups, billing of failed lookups, SDKs and MCP, plus a bake-off script.
12 min read
Developers
What syntax, MX, disposable-domain and mailbox checks can tell you without sending mail, why SMTP probing gives false answers, and tested code in Node, Python and PHP.
11 min read
Guides
Indonesian numbers: the +62 format, why mobiles have 9 to 12 digits, the 08XX prefixes, tested validation code, no mobile porting, and Komdigi's 2026 SIM registration rules.
11 min read
Guides
Check an Indonesian customer list for WhatsApp: fix 08, 62 and 8 formats to +62, dedupe, get a free estimate, and stay within the PDP Law (UU 27/2022).
13 min read
Guides
Three free ways to check if a number is on WhatsApp without adding a contact, what the wa.me 'invalid' message means, and how to format numbers by country.
11 min read
Guides
French phone number format: +33 plus 9 digits, 06/07 mobiles, Arcep prefixes, tested validation code, RIO porting, opt-in sales calls and SMS consent.
24 min read
Guides
India phone number format: +91 plus 10 digits, mobile prefixes 6-9, tested validation code, porting (MNP) rules, DLT sender rules and the 140/1600 series.
18 min read
Guides
Italian phone number format: +39, 3xx mobiles with 9 or 10 digits, landlines that keep the 0, tested validation code, porting, the RPO and anti-spoofing.
22 min read
Guides
Japanese phone number format: +81 and 11-digit 070/080/090 mobiles, 050, 020 and 0120 ranges, tested code, one-stop porting and opt-in SMS rules.
22 min read
Guides
Why phone lists match poorly in Meta Custom Audiences: missing country codes, dead and recycled numbers, landlines. The format Meta expects and a cleanup order.
11 min read
Guides
Nigerian numbers: the +234 format, the 070, 080, 081, 090 and 091 mobile prefixes, tested validation code, 48-hour porting, NCC's DND 2442 and NIN-SIM rules.
12 min read
Fraud prevention
No public list ranks SMS pumping countries. How to sort destinations into allow, gate and block from published sources and your data, and which ranges to block.
12 min read
Guides
South Korean phone number format: +82 and 11-digit 010 mobiles, area codes, 070 and 1588 numbers, tested code, porting and the ad-label SMS rules.
22 min read
Guides
Spanish phone number format: +34 plus 9 digits, 6/7 mobiles, 8/9 landlines, tested validation code, 1-day porting, 400 numbers for sales calls and SMS rules.
20 min read
Guides
Australian phone number format: +61, 10-digit 04 mobiles, area codes, tested validation code, porting since 2001 and the SMS Sender ID Register.
17 min read
Guides
Colombia phone number format: +57 and 10-digit 3XX mobiles, the 2021 60X landline change, tested code, porting, Ley 2300 contact hours and WhatsApp checks.
19 min read
Guides
German phone number format: +49, variable-length numbers, 015/016/017 mobile prefixes, tested validation code, porting since 2002 and UWG consent rules.
18 min read
Guides
Kenya phone number format: +254 and 9-digit 07/01 mobiles, the CA's operator prefixes, tested code, 4-hour porting, SIM registration and SMS marketing rules.
19 min read
Guides
Nepal phone number format: +977 and 10-digit 9XX mobiles, NTC and Ncell prefixes, tested code, why porting isn't live yet, and NTA's SMS and privacy rules.
18 min read
Guides
US phone number format: +1 plus 10 digits (NPA-NXX-XXXX), US vs Canada area codes, tested validation code, porting, 10DLC, TCPA and the FCC reassigned database.
18 min read
Research
We counted all 11,467 published FCC Robocall Mitigation Database filings: 42% certify full STIR/SHAKEN, 36% rely on mitigation only. Data and method.
8 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
Guides
Pakistani numbers: the +92 format, which 03XX codes are mobile, tested validation code, porting, PTA's short-code and consent rules, and the 3627 register.
11 min read
Guides
What TRAI's TCCCPR Third Amendment of 18 September 2026 changes: AI spam flagging, A2P call declaration, 6-hour header suspension, 7-day inquiry consent, 140/1600/1601.
9 min read
Fraud prevention
How silent network authentication (CAMARA Number Verification) and flash-call verification work, their coverage limits, and where pre-checks still help.
6 min read
Research
Mobile number portability in 68 countries: launch dates, porting times and published volumes, with a source per row, plus why prefix carrier lookups fail.
10 min read
Fraud prevention
OTP bombing floods a phone with codes from your send-code endpoint. A rate-limit recipe by number, IP, device and prefix, with pre-send checks.
7 min read
Developers
How AI coding agents read API docs: llms.txt, Markdown twins, OpenAPI and MCP. Set up Claude Code or Cursor, with an AGENTS.md snippet you can copy.
8 min read
Guides
What the TCPA revoke-all opt-out rule required, why it was delayed to 31 January 2027, how the FCC's September 2026 order (FCC 26-67) replaces it, and an opt-out data model. Not legal advice.
11 min read
Guides
Phone validation checks the number; verification proves the user holds it. What each one stops, what they cost, and how to combine them in one flow.
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
Guides
Thailand phone number format: +66 and 10-digit mobiles (06, 08, 09), the 0066 parsing trap, tested code, porting, SIM identity rules and LINE checks.
17 min read
Guides
To check if a Yahoo email exists, send a test message and read the bounce, or run an account check in bulk. SMTP probes fail at Yahoo; here is why.
15 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
Guides
MCC and MNC codes identify every mobile network. How the ITU E.212 system works, how to read a code like 310260, MCC vs calling code, and a list by country.
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
Fraud prevention
You can check whether a Netflix, Amazon or Microsoft account uses a phone number (yes, no or unknown), but never see the account itself. How fraud teams use it.
10 min read
Guides
To check if a number is linked to an X (Twitter) account, send it to a registration check: you get registered, not registered or unknown, never the handle.
11 min read
Developers
Code to validate Indian mobile numbers: what ^[6-9]\d{9}$ misses, normalising +91, 0 and 0091, and tested JavaScript, Python, PHP and C# functions.
8 min read
Guides
Sri Lankan mobiles are +94 plus 9 digits starting with 7 (07X at home). Operators by prefix, tested code, porting status, SMS rules and PDPA dates.
14 min read
Guides
Vietnamese mobiles are +84 plus 9 digits (10 with the leading 0) since the 2018 switch from 11 digits. Prefixes, tested code, porting and anti-spam rules.
17 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
Fraud prevention
Free ways to run a phone number reputation lookup (regulator complaint data, phone labels, report sites), their limits, and when an API score is worth it.
10 min read
Fraud prevention
How promo abuse and multi-accounting work, which phone signals help, and friction tiers that stop repeat claims without punishing real customers.
7 min read
Developers
Verify Standard Webhooks HMAC signatures in Node.js and Python: raw bodies in Express, Next.js and FastAPI, timestamps, replays, and why checks fail.
7 min read
Guides
Argentine numbers: why mobiles are +54 9 at home 0 + area code + 15, area codes of 2 to 4 digits, tested validation code, porting and the No Llame register.
15 min read
Guides
Bangladeshi mobiles are +880 plus 10 digits starting 1 (01X at home: 011, 013-019). Since porting began in 2018, the prefix no longer proves the network.
13 min read
Guides
Free carrier lookup methods (prefix data, regulator tables, web tools), why they fail for ported numbers, and when a paid live lookup is worth it.
10 min read
Guides
Malaysian mobiles are +60 1X plus 7 digits, or +60 11 plus 8, so a fixed 10-digit rule rejects valid 011 numbers. Prefixes, tested code, porting, MCMC rules.
14 min read
Guides
Check if a Gmail, Yahoo or Outlook account exists without sending mail: why SMTP probes fail at big providers, address aliases, bulk lists and privacy.
9 min read
Guides
Check if a phone number has a Facebook or Instagram account: a yes, no or unknown answer with a date, never a profile. Real time or bulk, with WhatsApp.
10 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
Fraud prevention
How to tell if a phone number is fake at sign-up, in a lead form or on a list: format, line type, network status, app presence, reputation and patterns.
11 min read
Guides
Is a WhatsApp number check legal? GDPR, India's DPDP Act, Brazil's LGPD, Malaysia's PDPA and US rules, and why registration is not permission to message.
10 min read
Guides
WhatsApp usernames hide phone numbers from new contacts, but accounts still sit on a number. What changes for businesses, the Cloud API and number checks.
7 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
Fraud prevention
What STIR/SHAKEN attestation levels A, B and C mean, what they don't prove, how they relate to spam labels, and the rules in the US, Canada and France.
8 min read
Guides
Chinese mobiles are +86 plus 11 digits starting with 1 (blocks 13-19), no trunk 0; landlines use area codes. Operator blocks, tested code and porting.
11 min read
Guides
Hong Kong phone number format: +852 and 8 digits, no area codes or trunk 0, which first digits are mobile, tested validation code, porting and SIM rules.
13 min read
Guides
Macau phone number format: +853 and 8 digits with no area codes, mobiles in the 62, 63, 65, 66 and 68 blocks, tested validation code and the Hong Kong overlap.
13 min read
Guides
Check Telegram numbers in bulk for Indonesia, India, the Philippines, Vietnam, Hong Kong and more: normalising Asian formats, privacy and unknowns, cost caps.
7 min read
Guides
Check WhatsApp numbers in bulk: prepare a CSV, get a free estimate, cap the cost, run the job in the dashboard or API, and act on each answer.
8 min read
Guides
How to check if a phone number has an Apple ID (Apple Account), one or in bulk: what yes, no and unknown mean, how it differs from iMessage, API examples.
7 min read
Developers
No. libphonenumber checks numbering-plan metadata, not the network. What isValidNumber proves, what it can't, and how to check if a number is live.
7 min read
Fraud prevention
Attackers change an account's phone number before resetting everything else. A checklist to secure the change-number flow without locking out real users.
7 min read
Guides
MCC/MNC lookup by phone number: why the prefix shows only the original network, how to get the current code with MNP or HLR, and 5 mistakes to avoid.
8 min read
Developers
The phone validation ladder: syntax, numbering plan, line type and live checks, with the right library for JavaScript, Python, PHP, Go and Java.
7 min read
Developers
Validate phone numbers in Java and Kotlin with libphonenumber: Maven setup, E.164, a Spring Bean Validation constraint, Android notes and a live lookup.
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
Guides
A Signal number lookup can only say whether a findable Signal account uses a number you hold, never whose it is. What the check sees and when not to use it.
7 min read
Guides
A dated TCPA checklist for SMS: consent, opt-out words, 10-day revocation, quiet hours, do-not-call, reassigned numbers and list hygiene. Not legal advice.
9 min read
Fraud prevention
Why identity and messaging providers block voice and SMS codes as suspected toll fraud, what triggers it, and a pre-call check recipe for developers.
7 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
Guides
What the IMSI, MSISDN, ICCID and IMEI are, where each lives, what changes when you port or swap a SIM, and why the IMSI must never leave the network.
8 min read
Guides
A non-fixed VoIP number works from anywhere over the internet. What it's used for, how it differs from fixed VoIP, and how to tell if a number is VoIP.
7 min read
Fraud prevention
Phone number reputation is a score built from complaints, reports and call patterns. Where the data comes from, what it can't tell you and how to use it fairly.
7 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
Developers
Validate phone numbers in Go with nyaruka/phonenumbers, format E.164, and call a lookup API with context timeouts, rate limiting and 429 back-off.
7 min read
Guides
Absent subscriber: the number exists but the phone is off or out of reach. Unknown subscriber: the number is not assigned. Each HLR result and what to do next.
10 min read
Developers
Each phone signal goes stale at its own speed. How often to re-verify numbers, how to cache HLR, MNP and messaging-app answers, and how long to keep them.
8 min read
Fraud prevention
Turn carrier, line type, network status and reputation signals into a phone number risk score with three outcomes, reason codes and calibrated thresholds.
8 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
Guides
The FTC's 31-day National Do Not Call Registry scrub, the safe-harbor conditions, penalties, and what a carrier or spam-reputation check can and can't do before you dial. Not legal advice.
6 min read
Developers
How to use the Idempotency-Key header to retry POST requests without double-processing: MobileValidate's rules, tested-pattern retry code for Node.js and Python, and which errors are safe to retry.
6 min read
Developers
How to design a phone number field that captures correct, consented numbers: one field, a smart country default, tel autofill, helpful errors and E.164.
8 min read
Guides
What role-based e-mail addresses are, when to accept, flag or ask for a personal address, and how to detect them without false positives.
8 min read
Guides
How phone numbers differ by country: formats and E.164, numbering changes, portability, line types, messaging channels, and a dated tracker of calling and texting rules.
11 min read
Developers
How AI agents check phone numbers and e-mail addresses safely: MCP server or function calling, which files an agent should read first, spend caps, and guardrails.
9 min read
Guides
E-mail verification explained step by step: syntax, MX, mailbox, catch-all, disposable and bounce checks, account signals, privacy rules, and which check fits which job.
10 min read
Guides
To check if a number uses iMessage, run a bulk iMessage check (yes, no or unknown). Find your own iMessage ID in Settings, plus blue vs green bubbles and RCS.
7 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
Guides
To check if a phone number is active, validate it, then run a carrier or HLR lookup for live status; app checks show registration. Free methods and limits.
8 min read
Fraud prevention
IRSF is fraud where attackers trigger calls or texts to numbers they profit from. No free IRSF number database exists; use range lists and line-type checks.
8 min read
Guides
What a registration check tells you for WhatsApp, Telegram, Viber, Signal, iMessage, RCS, LINE, Zalo and more: modes, unknowns, billing and consent.
9 min read
Fraud prevention
Before sending an OTP, look up the number: number type, line type and carrier, HLR status, porting. Which APIs offer it, what to compare, a pre-send flow.
10 min read
Developers
To validate a phone number in Python, parse it with phonenumbers, check is_valid_number and store E.164. Exact NumberParseException errors, Pydantic and pytest.
9 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
Guides
How Telegram's phone and username model differs, what a registration check can and can't tell you, how privacy settings affect it, with API examples.
7 min read
Guides
To tell if a WhatsApp number is a business account, open its profile (business details, blue check for official accounts) or run a business check in bulk.
8 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
Developers
How a WhatsApp registration check works, what registered, not registered and unknown mean, and how to call it responsibly from cURL, Node and Python.
9 min read
Guides
Mailbox validation says an address can receive mail. An account check says it is registered on a service. When to use each, and the privacy rules.
8 min read
Guides
What carrier and line type data is, allocated vs current network, how porting changes it, and how to read every field of a carrier lookup answer.
8 min read
Developers
How to normalize phone numbers to E.164 in JavaScript and Python, the pitfalls that break deduplication, and how the MobileValidate API normalizes input.
9 min read
Developers
The common E.164 regex accepts impossible numbers. Real counterexamples, the shortest valid international numbers, and what to use a regex for instead.
7 min read
Guides
Validation checks the digits, MNP finds the current network, HLR asks the network if the number is live. What each answers, costs and misses.
7 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
Fraud prevention
A layered sign-up defence: format, line type, messaging presence, spam reputation and e-mail checks, mapped to friction tiers you can measure.
8 min read
Guides
A number's prefix shows the network its range was given to, not the one serving it today. How porting works, where lookups fail and how to handle it.
7 min read
Research
We counted 182 phone-metadata releases from 2019 to 2026: a median of 14 days apart, and 223 of 238 regions changed. Why validation goes stale.
8 min read
Developers
How to give an AI agent phone and e-mail checks through the MobileValidate MCP server: tools, example prompts, real tool calls and spend safeguards.
9 min read
Fraud prevention
A call-center workflow for routing inbound calls by spam reputation: levels, reasons, STIR/SHAKEN, limits of the data, and why no_reports isn't safe.
8 min read
Fraud prevention
What a SIM swap is, which SIM-swap data exists and who can get it, and which signals to combine before you trust an SMS code when that data is missing.
9 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
Research
Our analysis of 362,116 FTC Do Not Call complaints and FCC unwanted-call data: top subjects, robocall share, weekday pattern and trend.
8 min read
Fraud prevention
Why VoIP numbers matter at sign-up, fixed vs non-fixed VoIP, which signals detect them, and how to add friction without turning away real customers.
8 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
Guides
When a phone number is personal data under the GDPR, what changes for business numbers, and how lookups and enrichment fit lawful basis, notice and rights.
10 min read
Guides
The criteria that matter when you choose a phone-intelligence API: coverage, conclusive rates, unknown billing, latency, freshness, privacy and test mode.
9 min read
Developers
Validate phone numbers in JavaScript with libphonenumber-js: min vs max metadata, E.164, form input, and a live line-type check with runnable Node code.
9 min read
Guides
A practical GDPR-oriented checklist for phone and e-mail checks: purpose, lawful basis, minimisation, retention, objections, rights, DPAs and logging.
9 min read
Guides
What the FCC Reassigned Numbers Database does, how its yes/no/no-data answers and TCPA safe harbor work, what it costs, and where other checks fit.
8 min read
Developers
Validate phone numbers in PHP with libphonenumber-for-php, write a Laravel rule, and add a live line-type check with Guzzle that never breaks the form.
7 min read
Fraud prevention
How SMS pumping (artificially inflated traffic) drains OTP budgets, the signals that give it away, and a layered checklist to stop it before you pay.
8 min read
Topics
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.
