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IsValid.dev VS NumValidate

Compare IsValid.dev VS NumValidate and see what are their differences

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Contents:
  1. ยป Base Details
  2. ยป Reviews
  3. ยป Alternatives

IsValid.dev logo IsValid.dev

A powerful REST API for validating emails, IBANs, BIC/SWIFT codes, LEI, ISIN, credit cards, VAT numbers, phone numbers, and 70+ more validators. Free tier available.

NumValidate logo NumValidate

Phone number validation REST API. Simple, Free, and Open Source.
  • IsValid.dev Main Page
    Main Page //
    2026-04-09

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.

  • NumValidate Landing page
    Landing page //
    2020-03-16

IsValid.dev features and specs

  • Lightweight schema validation
    IsValid.dev offers a minimal, lightweight approach to schema validation for TypeScript, avoiding the bloat that can come with larger validation libraries.
  • TypeScript-first design
    Built with TypeScript in mind, providing strong type inference so validated data automatically gets proper TypeScript types without extra manual typing.
  • Simple API
    The library offers an intuitive and easy-to-learn API for defining and running validations, making it accessible for developers to quickly get started.
  • Zero or minimal dependencies
    Being a lightweight tool, it typically has little to no external dependencies, reducing bundle size and potential security/maintenance issues from third-party packages.
  • Good for small to medium projects
    Its simplicity makes it well suited for smaller projects or use cases where heavier libraries like Zod or Yup might be overkill.

Possible disadvantages of IsValid.dev

  • Smaller community and ecosystem
    Compared to established validation libraries like Zod, Joi, or Yup, IsValid.dev has a much smaller user base, meaning fewer community resources, tutorials, and third-party integrations.
  • Limited documentation
    As a newer or less mainstream tool, its documentation may be less comprehensive than more established alternatives, making it harder to find answers to edge-case questions.
  • Fewer advanced features
    It may lack some of the advanced features found in more mature libraries, such as extensive built-in validators, custom error message localization, or complex schema composition tools.
  • Less battle-tested
    Being less widely adopted, it may not have been tested against as many real-world edge cases as more popular libraries, potentially leading to undiscovered bugs.
  • Uncertain long-term support
    Newer or niche libraries carry a higher risk of reduced maintenance or discontinuation over time compared to well-funded or widely-adopted projects.

NumValidate features and specs

  • Easy Integration
    NumValidate offers simple APIs that make it easy to integrate phone number validation into applications, requiring minimal coding effort.
  • Global Coverage
    The service provides validation for phone numbers across multiple countries, making it versatile for international applications.
  • Real-time Validation
    It provides real-time phone number validation, which ensures accurate and up-to-date verification of phone numbers.
  • Accurate Formatting
    NumValidate returns phone numbers in standardized formats, which helps maintain consistency in data across platforms.
  • Fraud Prevention
    By verifying phone numbers, NumValidate helps in identifying and reducing fraudulent activities associated with fake or invalid phone numbers.

Possible disadvantages of NumValidate

  • Cost
    While NumValidate may offer a free tier, larger scale usage will incur costs, which might not be suitable for all budgets.
  • Dependency on Internet Connection
    As a web-based service, it requires a reliable internet connection to function, which might be a drawback for offline applications.
  • Privacy Concerns
    Sharing phone numbers with a third-party service could raise privacy concerns, especially for applications dealing with sensitive information.
  • Limited Offline Access
    Since it relies on API calls, users need an active service for number validation, limiting offline usability.
  • Potential Latency
    Depending on the location of their servers and the user's internet speed, there might be some latency during validation, affecting user experience.

Analysis of IsValid.dev

Overall verdict

  • IsValid.dev appears to be a developer-focused validation/utility tool that can be useful for quick, lightweight validation tasks, though I don't have verified, up-to-date details on its full feature set or reliability track record.

Why this product is good

  • Likely offers a simple, developer-friendly interface for validation tasks
  • Probably free or low-cost, making it accessible for quick checks
  • May support common validation formats (e.g., JSON, schemas, or data formats) useful in development workflows
  • Could save time compared to writing custom validation scripts for simple use cases

Recommended for

  • Developers needing quick, ad-hoc validation checks
  • Small projects or prototypes where a lightweight tool suffices
  • Users looking for a free or low-cost alternative to more complex validation suites
  • Learning or testing purposes rather than mission-critical production validation

Category Popularity

0-100% (relative to IsValid.dev and NumValidate)

IsValid.dev

NumValidate

Developer Tools
36 36%
Developer Tools
64% 64
Phone Number Validation
0 0%
Phone Number Validation
100% 100
API
36 36%
API
64% 64
Phone Number Verification
0 0%
Phone Number Verification
100% 100

Questions & Answers

As answered by people managing IsValid.dev and NumValidate.

What makes your product unique?

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.

Why should a person choose your product over its competitors?

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.

How would you describe the primary audience of your product?

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.

What's the story behind your product?

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.

Which are the primary technologies used for building your product?

IsValid.dev's answer

Next.js, Fastify, PostgreSQL, Docker

User comments

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What are some alternatives?

When comparing IsValid.dev and NumValidate, you can also consider the following products

Abstract APIs - Simple, powerful APIs for everyday dev tasks

Numverify - Global phone number validation and lookup API

Antideo - Email, IP address and phone number validation API service

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.

Numlookupapi.com - Our phone number lookup & validation API is the perfect tool to automate fraud protection & clean your database.

IBAN.com - IBAN checker is a software designed to validate an International Bank Account Number and identify the bank owning this account, BIC code and address.

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