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IsValid.dev
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IBAN.com
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MailValidation.io
CallApp is a Free Caller ID and Call Blocker app that allows mobile users to block phone calls, identify telemarketing calls, record phone calls, blacklist unwanted callers and much more. CallApp is one of the most comprehensive caller ID apps with the ability to identify over a billion unknown callers and update your contacts with full info from social media platforms.
IsValid is a validation API service for developers who need to quickly verify data formats without building their own validators. It offers 40+ endpoints covering financial identifiers (IBAN, BIC, ISIN, CUSIP), international standards (ISBN, ISSN), technology formats (UUID, JWT, QR codes), regional codes (PESEL, REGON, VAT), and more.
The service works on a freemium model โ 100 free API calls per day, no credit card required. Users manage API keys through a dashboard with usage analytics showing daily call volume and per-endpoint breakdowns.
CallApp
IsValid.devThis app is recommended for individuals looking to reduce spam and scam calls, people who want detailed insights into their callers, and those who appreciate additional features like call recording. It is also suitable for users who want a more personalized and controlled calling experience on their Android devices.
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IsValid.dev's answer:
IsValid offers 70+ validators in a single API โ covering financial identifiers (IBAN, BIC, ISIN, LEI), international standards (ISBN, ISSN), technology formats (UUID, JWT, QR codes), tax numbers (VAT, REGON, PESEL), credit cards, phone numbers, and more. No need to integrate multiple services for different data types.
IsValid.dev's answer:
Most validation APIs focus on one category (email or phone). IsValid covers financial, regional, and technical formats all in one place with a consistent REST API. The free tier with 100 calls/day requires no credit card, and integration takes minutes.
IsValid.dev's answer:
Developers and software teams building applications that handle user input, financial data, or international identifiers โ particularly in fintech, e-commerce, and SaaS products.
IsValid.dev's answer:
IsValid was built out of frustration with piecing together multiple validation libraries and services. The goal was a single, reliable API that handles the full range of data validation needs developers encounter in real-world applications.
IsValid.dev's answer:
Next.js, Fastify, PostgreSQL, Docker
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Abstract APIs - Simple, powerful APIs for everyday dev tasks
WhosCall - WhosCall is a reliable caller ID app whose popularity has led to its adoption by many users including international media. You can now manage the numbers calling you regardless of whether they are part of your contact list or not... read more.
Numverify - Global phone number validation and lookup API
Hiya - Know who's calling or texting and block spammers on Android
mailboxlayer API - Mailboxlayer is a free, simple and powerful JSON API offering instant email address validation & verification via syntax checks, typo and spelling checks, SMTP checks, free and disposable provider filtering, and much more.