UK Bank Account Validation API
Validate sort codes, account numbers, IBANs, and SWIFT/BIC codes in real time. 100% coverage of UK banks via the official EISCD dataset, updated weekly.
What Mintly's API Validates
Sort code validation
Verifies the sort code against the EISCD (Extended Industry Sort Code Directory), maintained by Vocalink/Pay.UK. Returns bank name, branch address, and supported payment types. Learn more in our sort code guide.
Account number modulus checking
Applies modulus checking algorithms 10 and 11 to confirm the sort code and account number pairing follows a valid mathematical pattern - catching transpositions and keying errors before they reach the payment network.
Payment type detection
Identifies which schemes the account supports: BACS, CHAPS, Faster Payments, and Direct Debit. Essential for routing payments correctly and avoiding failed submissions to unsupported schemes.
Global IBAN validation
Validates IBAN structure and country-specific check digits for 89 countries. Goes beyond basic format checks - our IBAN validation applies national check digit algorithms where they exist.
SWIFT/BIC validation
Verifies international bank identifiers against the global BIC directory. Returns the associated institution name and country, allowing you to confirm the beneficiary bank before initiating a cross-border payment.
Integrate in Minutes
A single REST call returns full validation results. Pick your language and copy the example - the sort code and account number below are real-format test values.
The API is fully RESTful with an OpenAPI 3.0 specification. Integration guides are available for Node.js, Python, C#, PHP, Salesforce, Power Automate, and Zapier — see integration guides or the API docs.
API Features
Everything a developer needs - fast data, clean responses, and full test coverage out of the box.
Response time
<60ms average, measured at API layer
Data source
EISCD — official Vocalink/Pay.UK sort code directory
Update frequency
Weekly data updates
UK coverage
100% of all registered sort codes
IBAN coverage
89 countries, full check-digit validation
Modulus algorithms
Modulus algorithms as used by all UK banks
Rate limits
Up to 1,000 req/sec (Professional plan)
Authentication
API key via HTTP header
Format
JSON, REST, HTTPS
Specification
OpenAPI 3.0 — importable into Postman, Insomnia
Sandbox
Full test environment with known pass/fail values
MCP Server
Compatible — integrate directly with Claude and AI agents
Simple Pricing - Try Free for 14 Days
No credit card required for your free trial. Cancel or change plan any time.
Starter
£37
per month
- 250 requests/month
- Up to 10 req/sec
- Full API access
- Sandbox included
Standard Plus
£96
per month
- 10,000 requests/month
- Up to 100 req/sec
- Full API access
- Sandbox included
Professional
£157
per month
- 25,000 requests/month
- Up to 1,000 req/sec
- Full API access
- Sandbox included
All plans include a 14-day free trial with no credit card required. Enterprise and volume plans available - contact us.
Built for Production. Trusted by UK Businesses.
- VocaLink Authorised Distributor - direct data provenance chain to Pay.UK, the operator of the EISCD
- Crown Commercial Service G-Cloud 14 Lot 2 supplier - available to UK public sector without a separate procurement process
- Cyber Essentials certified - NCSC-accredited baseline security certification
- GDPR compliant & UK data residency - data processed and stored within the United Kingdom
- 99.95% uptime SLA (Enterprise plans) with a public status page
Mintly is built to meet the security and compliance requirements of enterprise procurement teams.
Account numbers submitted to the bank account validation API are never persisted. Each validation request is processed in real time against our hosted EISCD dataset and discarded immediately after the response is returned.
Common Use Cases
The bank account validation API fits wherever UK payment data enters or leaves your system.
Pre-BACS submission checks
Validate account details before submitting BACS files to eliminate return items and Bacs Service User charges. A single failed payment can cost more than the annual subscription — catching invalid accounts at source is the simplest risk control available.
Direct Debit AUDDIS onboarding
Verify new payer account details at sign-up before the first AUDDIS instruction is submitted, reducing failed first collections. Validating at onboarding — rather than on payment day — prevents the customer churn that follows a failed first Direct Debit.
Customer onboarding forms
Inline validation on payment or banking detail capture forms prevents incorrect data from entering your system at source. Integrate the sort code validation API directly into your web form to surface errors in real time, before the customer clicks submit.
Payroll and B2B payments
Validate supplier or employee bank details before payment runs to eliminate manual re-work from failed payments. Modulus checking catches the transposition errors that are common when employees self-report account numbers via HR systems.
Frequently Asked Questions
Does the API store the bank account numbers I submit?
No. Mintly does not persist account numbers submitted via the API. Each request is validated in real time against our hosted EISCD dataset and discarded immediately.
What's the difference between sort code validation and modulus checking?
Sort code validation confirms the sort code exists in the EISCD directory and returns bank and branch details. Modulus checking is an additional layer that mathematically verifies the sort code and account number combination follows the correct pattern — catching transpositions and keying errors that sort code validation alone cannot detect.
Is there a sandbox environment for testing?
Yes. All plans include access to a full sandbox with documented test cases for valid accounts, invalid sort codes, and modulus check failures. See the API docs for the complete list of test values.
What happens if a sort code isn't in the EISCD?
The API returns a 404 result with a clear error code. Sort codes are removed from the EISCD when a branch closes — if you're seeing unexpected not-found results, the sort code may have been recently retired. Mintly ingests EISCD updates weekly, so the dataset is always current.
How current is the sort code data?
The EISCD is updated weekly. As a VocaLink Authorised Distributor, Mintly ingests each new release as it is issued — giving you the same authoritative dataset that the UK banking system itself relies on.
Can I use the API with Zapier or no-code tools?
Yes. Integration guides are available for Zapier, Power Automate, and Salesforce — no code required. See the integration guides for step-by-step instructions.
Start Validating in Minutes
No credit card required. 14-day free trial with up to 50 checks per day. Full API access from day one.
Questions? Contact us.