21 articles.
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
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
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
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
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
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
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
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
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
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 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
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
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
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
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
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
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
