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IsValid

Data Validation API for Emails, IBANs, ISIN, LEI & 70+ More

Stop writing validators from scratch. One REST API for emails, IBANs, domains, ISINs, ETH addresses, cron expressions, and 76+ validators — with checksum verification, DNS lookups, ESMA FIRDS data, GLEIF entity search, and UN/LOCODE built in.

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Validators: 76+
Free calls/day: 100
Uptime: 99.9%
SDKs: Node · Python · WP

Featured Validators

A closer look at the most powerful endpoints — enriched with live data from authoritative sources.

Legal Entity Identifiers

LEI Validation & Search

Validate Legal Entity Identifiers (ISO 17442) and instantly enrich them with entity data from the local GLEIF database — no external API calls, no rate limits. Search across 2.3 million entities by name with trigram similarity.

ISO 17442 format validation + mod-97 checksum (same as IBAN)
Local GLEIF Golden Copy database — ~2.3 million entities
Full-text name search with trigram similarity (pg_trgm)
LOU (Local Operating Unit) info returned for every valid LEI

GET /v0/leiView docs →

// GET /v0/lei?value=7LTWFZYICNSX8D621K86

{

"valid": true,

"lei": "7LTWFZYICNSX8D621K86",

"found": true,

"dataSource": "gleif-db",

"entity.legalName": "Deutsche Bank AG",

"entity.country": "DE",

"entity.entityStatus": "ACTIVE",

"entity.registrationStatus": "ISSUED",

"lou.name": "SWIFT"

}

Financial Instruments

ISIN Validation & Lookup

Validate International Securities Identification Numbers (ISO 6166) and instantly enrich them with instrument data. ESMA FIRDS and OpenFIGI are queried simultaneously — both sources merged into a single unified response.

ISO 6166 format validation + Luhn check digit
ESMA FIRDS — EU regulatory database (MiFID II, ~700k instruments)
OpenFIGI — global coverage (US equities and more)
Unified fields: FISN, CFI code, currency, venue, LEI, ticker, FIGI

GET /v0/isinView docs →

// GET /v0/isin?value=US0378331005

{

"valid": true,

"countryCode": "US",

"countryName": "United States",

"found": true,

"dataSource": "firds+openfigi",

"name": "Apple Inc.",

"fisn": "APPLE INC/SH SH",

"cfiCode": "ESVUFR",

"currency": "USD",

"tradingVenue": "HAMB",

"ticker": "AAPL",

"marketSector": "Equity"

}

International Banking

BIC / SWIFT Validation

Validate Bank Identifier Codes (ISO 9362) used in international wire transfers. 8- and 11-character BICs are supported — institution name, city, and branch lookup built in.

ISO 9362 format check — 8-character and 11-character BICs
Bank code, location code, and branch code breakdown
Institution name lookup from a built-in directory
City and branch name returned when available

GET /v0/bicView docs →

// GET /v0/bic?value=XASXAU2SRTG

{

"valid": true,

"bankCode": "XASX",

"countryCode": "AU",

"countryName": "Australia",

"locationCode": "2S",

"branchCode": "RTG",

"bankName": "ASX Operations Pty Limited",

"city": "Sydney",

"branch": "RTGS Settlement"

}

Bank Account Numbers

IBAN Validation

Validate International Bank Account Numbers (ISO 13616) for 80+ countries. Checks country-specific length, structure, and the full MOD-97 checksum — spaces and lowercase letters are handled automatically.

ISO 13616 format validation + MOD-97 checksum algorithm
80+ countries — EU and non-EU alike
Bank identification — name and BIC from 40+ national registries
BBAN extraction, EU membership flag, canonical formatted output

GET /v0/ibanView docs →

// GET /v0/iban?value=PL61109010140000071219812874

{

"valid": true,

"countryCode": "PL",

"countryName": "Poland",

"bban": "109010140000071219812874",

"isEU": true,

"formatted": "PL61 1090 1014 0000 0712 …",

"bankCode": "10901014",

"bankName": "PKO Bank Polski SA",

"bankBic": "BPKOPLPW"

}

Travel & Aviation

IATA Airport Code Validation

Validate 3-letter IATA airport codes and look up rich metadata for 250+ airports worldwide. Instantly retrieve the official name, served city, country, corresponding ICAO code, IANA timezone, and airport classification.

250+ airports across all continents
ICAO code, city, country, and IANA timezone returned
Airport classification: large_airport or medium_airport
Case-insensitive — WAW, waw, and Waw all accepted

GET /v0/iata/airportView docs →

// GET /v0/iata/airport?value=WAW

{

"valid": true,

"found": true,

"iata": "WAW",

"icao": "EPWA",

"name": "Warsaw Chopin Airport",

"city": "Warsaw",

"countryCode": "PL",

"countryName": "Poland",

"timezone": "Europe/Warsaw",

"type": "large_airport"

}

Business & Finance

Banking, payments, securities, and tax identifiers — with checksum verification, enrichment from authoritative databases, and real-time VIES checks.

🏦

IBAN

Validate International Bank Account Numbers for 80+ countries — MOD-97 checksum, bank name and BIC lookup for 40+ countries.

GET /v0/iban

🔀

BIC / SWIFT

Validate Bank Identifier Codes used in international wire transfers. Returns institution name, city, and branch from a built-in directory.

GET /v0/bic

💳

Credit Card

Luhn checksum validation with card network detection — Visa, Mastercard, Amex, Discover, JCB, Diners Club, and UnionPay.

POST /v0/credit-card

📈

ISIN

ISO 6166 validation with Luhn check digit. Enriches with instrument data from ESMA FIRDS and OpenFIGI — name, CFI, currency, venue, ticker.

GET /v0/isin

🏢

LEI

ISO 17442 validation with mod-97 checksum. Looks up entity data from a local GLEIF database of 2.3 million records. Supports name search.

GET /v0/lei

🧾

VAT

EU VAT number validation for all 27 member states with optional real-time VIES verification. Returns country, company name, and validity status.

GET /v0/vat

General Purpose

Everyday validators for contact data, networking, crypto, travel, and developer tokens.

📧

Email

RFC 5322 validation with optional DNS MX record checks to confirm the domain actually accepts mail.

GET /v0/email

📞

Phone Number

Validate phone numbers for 200+ countries. Returns country, calling code, line type, and E.164, national, and international formats.

GET /v0/phone

🌐

Domain

Validate domain names with full DNS resolution. Returns TLD, SLD, IDN detection, and A/AAAA record lookups via Google and Cloudflare DNS.

GET /v0/domain

⟠

ETH Address

Validate Ethereum addresses with EIP-55 mixed-case checksum verification. Returns the canonical checksummed address.

GET /v0/eth-address

✈️

IATA Airport

Validate 3-letter IATA airport codes with rich metadata — official name, city, country, ICAO code, IANA timezone, and classification.

GET /v0/iata/airport

🔑

JWT

Decode and validate JSON Web Tokens — header, payload, signature structure, registered claims, and expiration checks.

GET /v0/jwt

And 60+ more — Bitcoin address, IMEI, EAN / GTIN / UPC, IATA airline, MIC, URL, IP & MAC address, GPS coordinates, postal code, ISBN, ISSN, DOI, ORCID, ABA routing, NPI, CNPJ, CPF, ABN, NIF/NIE, GSTIN, EORI, Sort Code, NUTS, ISO 6346, SSCC, GLN, GS1 prefix, HS code, CAS number, barcode, QR / Data Matrix, NAICS / NACE industry, KRS, PESEL, REGON, DUNS, CEIDG, UUID, semver, CSS color, SWIFT MT, cron, regex, base64, DTI, CUSIP, CFI, and others. See full documentation →

TAC, SNR, and check digit explained — and why a 15-digit regex is not enough.

Read guide →

These are just a few of our guides — covering algorithms, edge cases, and production patterns. See all guides →

Official SDKs

Type-safe clients for Node.js and Python — with automatic retry, custom error classes, and full IntelliSense for every endpoint.

// Quick start

import { createClient } from '@isvalid-dev/sdk';

const iv = createClient({ apiKey: 'your-api-key' });

// Validate an email

const email = await iv.email('[email protected]');

// Country-specific validators

await iv.pl.pesel('44051401358');

await iv.iata.airport('WAW');

Node.js / TypeScript

npm install @isvalid-dev/sdk

Zero dependencies — native fetch only
Full TypeScript types for every response
ESM + CJS dual export — ~1.5 KB min+brotli
Automatic retry with exponential backoff

Get Started GitHub npm

# Quick start

from isvalid_sdk import IsValidConfig, create_client

iv = create_client(IsValidConfig(api_key='your-api-key'))

# Validate an email

email = iv.email('[email protected]')

# Country-specific validators

iv.pl.pesel('44051401358')

iv.iata.airport('WAW')

Python

pip install isvalid-sdk

Single dependency — httpx
Full type hints with TypedDict for every response
Context manager support
Automatic retry with exponential backoff

Get Started GitHub PyPI

[isvalid_input type="iban" label="IBAN" placeholder="GB29 NWBK 6016 1331 9268 19"]

[isvalid_input type="iban"

show="bankName:Bank name,countryName:Country"]

[isvalid_input type="email" label="Email address"]

WordPress Plugin

Add real-time validation to any WordPress site with a single shortcode. Works with Contact Form 7, WooCommerce checkout, Gravity Forms, and WPForms — no coding required.

80+ validators via [isvalid_input] shortcode
API key stays server-side — never exposed to the browser
Integrates with CF7, WooCommerce, Gravity Forms, WPForms
Output fields — auto-fill from API response data

View Plugin Documentation

Start validating today

Create your free account and get 100 API calls per day.

Frequently asked questions

Everything you need to know about the IsValid data validation API.

What is IsValid?

IsValid is a REST API for validating emails, IBANs, BIC/SWIFT codes, credit cards, LEI, ISIN, VAT numbers, phone numbers, and 70+ more identifiers. Every endpoint returns a JSON response with a "valid" boolean and additional metadata — bank names for IBANs, institution lookups for BICs, entity data for LEIs, instrument data for ISINs, and so on.

How do I get started with the IsValid API?

Create a free account at isvalid.dev, generate an API key from your dashboard, and send requests to https://api.isvalid.dev with an Authorization header. The free tier includes 100 API calls per day with no credit card required. Full code samples for Node.js, Python, and cURL are available in the documentation.

Is there a free plan?

Yes. The free tier includes 100 API calls per day across every validator, with no credit card required. Paid plans unlock higher quotas and priority support — see the pricing page for details.

Which validators are supported?

The API currently exposes 76+ validators grouped into financial identifiers (IBAN, BIC/SWIFT, ISIN, LEI, CUSIP, SEDOL, VALOR, WKN, MIC, CFI, DTI, credit card), regulatory and tax identifiers (VAT, EORI, GSTIN, NPI, CPF, CNPJ, PESEL, REGON, KRS, NIF), logistics and commerce identifiers (GLN, SSCC, EAN/GTIN, HS code, UN/LOCODE, container code, IATA airport/airline/flight), and general-purpose validators (email, phone, domain, IP address, UUID, JWT, URL, VIN, MAC address, ETH and BTC addresses, QR code, semver, date, postal code). A full list is in the docs.

Does the API verify data against real-world registries?

Yes. IBAN responses include bank names for 40+ countries, BIC lookups resolve to institution names, LEI validation queries a local GLEIF Golden Copy database of 2.3 million entities, ISIN validation enriches with ESMA FIRDS and OpenFIGI instrument data, VAT numbers can be verified against the EU VIES registry, and emails can be checked against live DNS MX records.

How fast is the API and where is it hosted?

Most requests complete in under 50 ms because reference datasets (GLEIF, FIRDS, UN/LOCODE, bank directories) are stored locally and queried directly from PostgreSQL. The service is hosted in Europe and runs behind a load-balanced, zero-downtime deployment.

Can I use IsValid for GDPR-compliant workloads?

Yes. The service is operated by creact.dev sp. z o.o. in the European Union and only stores the data required to operate your account and bill usage. Validation payloads are not retained beyond the response. See the privacy policy for the full data-processing statement.

Do you provide SDKs or code samples?

Every validator page in the guides section includes ready-to-copy Node.js and Python examples using the standard fetch and requests libraries — no SDK install required. The docs page lists every endpoint with request and response schemas.

Ready to integrate IsValid into your project?

Read the full API documentation and start making requests in minutes.

Getting Started Read the Docs