validation.vin
Check a 17-character vehicle identification number and its check digit; enforced for North American VINs.
validate_vin in PythonResults for “validation”
100 capabilities
validation.uk-utr
Check an HMRC Unique Taxpayer Reference's modulus 11 check digit, accepting the K and spacing people type.
validate_uk_utr in Python
validation.email
Is this a plausible email address? A documented, pragmatic subset of RFC 5322, not the full grammar.
is_email in Python
validation.lei
Check a 20-character Legal Entity Identifier against its ISO 17442 / ISO 7064 MOD 97-10 check digits.
validate_lei in Python
validation.iban
Check an IBAN against the ISO 13616 mod-97-10 checksum and the registered length for its country.
is_iban in Python
validation.luhn
Check a digit string against the Luhn mod-10 checksum used by payment cards and many identifiers.
is_luhn in Python
validation.uk-ni-number
Check a UK National Insurance number's format and HMRC's disallowed prefix letters, and normalise it.
validate_uk_ni_number in Python
validation.uk-postcode
Validate a UK postcode and normalise it to canonical upper case with one space before the inward code.
validate_uk_postcode in Python
auth.validate-registration
Validate a sign-up form (email, password, name) in one call, with a message per field, in the browser and the API alike.
validate_registration in Python
validation.uk-vat-number
Check a UK VAT registration number against HMRC's mod-97 checksum, including the post-2010 9755 variant.
is_uk_vat_number in Python
validation.nhs-number
Check an NHS number's modulus 11 check digit and normalise it to ten digits.
validate_nhs_number in Python
validation.isbn
Check an ISBN-10 or ISBN-13 and convert between them; the normalised form is always the ISBN-13.
validate_isbn in Python
validation.uk-sort-code-account
Check a UK sort code and account number with the Vocalink/Pay.UK modulus rules, against a table you supply.
validate_uk_sort_code_account in Python
net.device-validate
Validate one network inventory entry: name, host, ports, optional MAC and subnet, with every problem listed.
validate_device in Python
validation.uk-modulus-table
Parse Vocalink's VALACDOS.txt and SCSUBTAB.txt into the table UK sort code modulus checking needs.
parse_uk_modulus_table in Python
validation.gs1-check-digit → isGs1CheckDigitValid
Compute or check the GS1 mod-10 check digit of any GS1 key: GTIN, SSCC, GLN, GSRN, GDTI, GSIN and the rest.
is_gs1_check_digit_valid in Python, one function of this group
auth.validate-login
Check a login form (email, password): the normalised email to look up, or a message for each field to fix.
validate_login in Python
validation.bic
Check the format of a SWIFT/BIC code (8 or 11 characters) and split it into its parts.
validate_bic in Python
validation.uk-company-number
Check a Companies House company number's format and prefix (SC, NI, OC, LP...) and zero-pad it to eight characters.
validate_uk_company_number in Python
validation.gtin
Check an EAN-8, UPC-A, EAN-13 or GTIN-14 barcode number against the GS1 mod-10 check digit.
validate_gtin in Python
finance.ledger.journal-validate
Check a double-entry journal: debits equal credits, no zero or two-sided lines, one currency, well-formed account codes.
validate_journal in Python
validation.phone-e164
Normalise a phone number to E.164 (+447700900123) using a default country's trunk and dialling prefixes.
validate_phone_e164 in Python
auth.validate-password-change
Check a change-password form: current password given and correct, new one meeting the policy and different.
validate_password_change in Python
health.qrisk-inputs-validate Unreviewed
Check a QRISK3 cardiovascular risk input set against the calculator's published ranges; does not compute risk.
validate_qrisk_inputs in Python
todo.item → validateDraft
The to-do item type (Todo, TodoDraft, Recurrence) and its validators, with a message per field.
validate_draft in Python, one function of this group
retail.coupon-validate
Check a coupon against a basket: dates, usage limits, eligible products and minimum spend, with reason codes.
validate_coupon in Python
net.hostname-validate
Check a host name against RFC 1123 and RFC 952 label rules and length limits, and normalise it.
validate_hostname in Python
form.date-parts
Check a date typed into day, month and year boxes, with GOV.UK's error messages and the boxes to mark in error.
validate_date_parts in Python
logistics.hs-code-validate
Check the format of a commodity code: 6-digit HS, 8-digit CN or 10-digit TARIC/UK code, with chapter and heading checks.
validate_hs_code in Python
net.mac-address
Validate a MAC address in colon, hyphen, Cisco dot or bare form and normalise it, with multicast and local bits.
validate_mac_address in Python
react.form.error-summary React ^19 · TypeScript only
A "There is a problem" box linking to each field in error, focused on arrival, built from a validator's fields (GOV.UK).
Not available in Python
form.state TypeScript only
A form's state as a pure reducer: values, touched fields, validator errors and the submit, for useReducer.
Not available in Python
todo.import-csv → validateTodoCsv
Read todos from a CSV file (RFC 4180) as todo.export-csv writes it, checking every row, with row-numbered errors.
validate_todo_csv in Python, one function of this group
net.ipv4
Parse, format and check dotted-quad IPv4 addresses, refusing leading zeros, octal, hex and short forms.
A group of 3:
parse_ipv4, format_ipv4, is_ipv4
auth.password-policy
Check a new password against a named policy (NIST SP 800-63B-4 by default): length, common passwords, name and email.
A group of 2:
password_policy, check_password
health.nhs-number-format Unreviewed
Display an NHS number in the 3-3-4 format ("943 476 5919") after checking its modulus 11 check digit.
format_nhs_number in Python
monitor.cert-expiry
How long a TLS certificate has left before its notAfter, and whether that is ok, a warning, critical or expired.
cert_expiry in Python
auth.normalise-email
Trim an email address and lower-case its domain for storage and lookup, or null if it is not a plausible address.
normalise_email in Python
energy.price-cap
Ofgem energy price cap unit rate and daily standing charge for a fuel and payment method on a date (GB average).
price_cap in Python
finance.uk-bank-rate
Bank of England Bank Rate (base rate) in force on a date, from the Bank's official history since 2001.
uk_bank_rate in Python
logistics.freight-rate
Freight charge from a carrier's dated weight-break tariff for a zone, with the fuel surcharge in force on the ship date.
freight_rate in Python
retail.shipping-rate
Delivery charge from a dated rate table by service, zone, chargeable weight and size, with a free-over threshold.
shipping_rate in Python
auth.jwt
Sign, verify and decode HS256 JSON Web Tokens (RFC 7519): signature, algorithm and exp/nbf/iat checked with leeway.
A group of 3:
sign_jwt, verify_jwt, decode_jwt
react.form.date-input React ^19 · TypeScript only
Day, month and year boxes under one legend, with hint, error message and the boxes in error marked (GOV.UK date input).
Not available in Python
energy.climate-change-levy
Climate Change Levy on a business supply of electricity, gas, LPG or solid fuel, at the main rate in force on the date.
climate_change_levy in Python
todo.parse-quick-add
Turn one typed line like "Pay rent tomorrow !high #home every month" into a todo draft.
parse_quick_add in Python
auth.access-token
Issue an API's HS256 access token, read one from an Authorization header, and refuse revoked or superseded ones.
A group of 3:
issue_access_token, read_access_token, confirm_access_token
finance.compound-interest
Compound interest accrued period by period in minor units, the way a statement is built.
compound_interest in Python
finance.tax.vat-rate Unreviewed
Look up the VAT rate in force for a jurisdiction, category and date.
vat_rate in Python
insurance.ipt Unreviewed
UK Insurance Premium Tax at the standard or higher rate in force on a date, added to or taken out of a premium.
insurance_premium_tax in Python
monitor.cert-check
A TLS certificate's expiry state as a check status: ok and warning are up, critical is degraded, expired is down.
cert_check in Python
health.news2 Unreviewed
NEWS2 early warning score from one set of observations: parameter scores, aggregate and RCP clinical risk band.
news2_score in Python
monitor.component-state
A status page component's state from its checks: operational, degraded, partial or major outage, or maintenance.
component_state in Python
banking.faster-payments-limit
Whether a Faster Payment fits the scheme maximum, the bank's per-payment limit and what is left of its daily limit.
faster_payments_check in Python
charity.reclaim-batch
Gift Aid claim totals for a period from donation records: donor lines, aggregated small gifts, tax due.
gift_aid_claim_batch in Python
logistics.sscc
Build an 18-digit SSCC pallet label number from extension digit, GS1 company prefix and serial, with its check digit.
build_sscc in Python
telecoms.roaming-charge
Roaming charges for a trip abroad from a dated tariff table of zones: daily fees, data, calls and texts.
roaming_charge in Python
energy.carbon-emissions
kgCO2e from kWh or litres of a fuel, using the UK government GHG conversion factors for the year.
carbon_emissions in Python
hospitality.tourist-tax
Visitor levy (tourist tax) on an overnight stay: Edinburgh's 5%, Cardiff's per person per night, or a caller's own rule.
tourist_tax in Python
crypto.constant-time-equal
Compare two byte strings in time that does not depend on where they differ, for checking MACs and hashes.
constant_time_equal in Python
finance.payment-terms-due-date
Invoice due date from payment terms: net N days, end of month, N days after month end, day N of next month.
payment_due_date in Python
money.parse
Parse "£1,234.50" or "1.234,50 €" into integer minor units, strictly: no guessing, no rounding.
parse_money in Python
net.port
Check a TCP/UDP port number and name the IANA service registered on it, with its system/user/dynamic range.
A group of 2:
is_port, port_service
retail.promotion-apply
Apply BOGOF, 3-for-2, percent off, amount off and multibuy deals to a basket, best for the customer, allocated to lines.
apply_promotions in Python
auth.bearer-token
The token from an HTTP Authorization header of the form "Bearer <token>" (RFC 6750), or null if it has none.
parse_bearer_token in Python
dates.days-between
Calendar days from one ISO date to another, signed: negative when the second date is earlier.
days_between in Python
dates.is-leap-year
Whether a year is a Gregorian leap year: every 4th, except centuries, except every 400th.
is_leap_year in Python
finance.ledger.trial-balance
Trial balance from journal lines: debit or credit balance per account, and proof that debits equal credits.
trial_balance in Python
react.form.textarea React ^19 · TypeScript only
A labelled multi-line text box with hint, error and an optional live character or word count (GOV.UK).
Not available in Python
todo.export-csv
Write todos as a CSV file (RFC 4180) with one column per field, for backups, spreadsheets and other apps.
export_csv in Python
todo.merge
Merge imported todos into a list by id: an imported todo replaces the one with its id, new ids are appended.
merge_todos in Python
todo.reschedule-recurrence
When a repeating todo's due date is moved by hand, move its series with it: the new date becomes the anchor.
reschedule_recurrence in Python
banking.cheque-amount-words
The words and figures to write on a cheque: "One hundred and twenty pounds and fifty pence only", "£120.50".
cheque_amount_words in Python
dates.business-days-between
Working days between two dates, excluding weekends and a caller-supplied holiday list.
business_days_between in Python
time.unix-to-iso
Unix time in seconds to an ISO 8601 UTC timestamp such as 2026-09-26T12:00:00Z, for years 0001 to 9999.
unix_to_iso in Python
todo.parse-tags
Read a tags box as typed, "#Home, work errands", into normalised tags: split on spaces and commas.
parse_tags in Python
todo.recurrence-label
English text for a repeating todo's chip: "Every weekday", "Every 2 weeks on Monday", "Every month on the 31st".
recurrence_label in Python
todo.normalise-tags
Clean up tags as typed: trim, drop the #, lower-case slug form, drop empties and duplicates, keep the order.
normalise_tags in Python
dates.add-business-days
Move a date forward or back by working days, skipping weekends and a caller-supplied holiday list.
add_business_days in Python
finance.early-payment-discount
Early settlement discount available on a payment date under "2/10 net 30" style terms, and the amount to pay.
early_payment_discount in Python
monitor.http-check-result
Classify one HTTP probe as up, degraded or down, with a reason and message, from status, body and latency.
classify_http_check in Python
todo.list
The to-do list reducer: add, edit, complete, remove, clear and reorder todos, each returning a new list.
A group of 8:
add_todo, update_todo, toggle_todo, remove_todo, clear_completed, toggle_all, move_todo, toggle_all_mode
health.gestational-age Unreviewed
Gestational age (weeks+days) and estimated due date from the last menstrual period by Naegele's rule, cycle-adjusted.
gestational_age in Python
health.waiting-time Unreviewed
NHS England referral-to-treatment (RTT) wait in days and weekly bands, with the 18-week breach flag.
rtt_waiting_time in Python
health.egfr Unreviewed
eGFR in mL/min/1.73 m² by the race-free CKD-EPI 2021 creatinine equation, from creatinine in µmol/L or mg/dL.
egfr_ckd_epi2021 in Python
health.bmi Unreviewed
Adult body mass index (kg/m², 1 decimal place) and its NICE/WHO weight category.
bmi in Python
health.bsa Unreviewed
Body surface area in m² by the Mosteller and the DuBois & DuBois formulas, to 2 decimal places.
body_surface_area in Python
health.dose-weight-based Unreviewed
Weight-based dose (per kg) capped at a maximum single dose and rounded to a measurable volume, in exact micro-units.
weight_based_dose in Python
health.appointment-slots Unreviewed
Bookable appointment slots from clinic sessions, a slot length, breaks and existing bookings.
appointment_slots in Python
health.age-in-months Unreviewed
Age in completed months and days on a given date, for paediatric charts and doses; month ends handled like birthdays.
age_in_months in Python
construction.retention
Retention held and released on a construction valuation: full rate, half at practical completion, none at the end.
retention in Python
construction.valuation
Interim valuation: gross value to date, retention, previous payments, amount due, VAT or reverse charge, and CIS.
interim_valuation in Python
manufacturing.tolerance-check
Check a measurement against a nominal size and its upper and lower deviations, in whole micrometres.
check_tolerance in Python
monitor.heartbeat-check
A heartbeat's state as a check status for a status page: up, late as degraded, down as down, new as nothing yet.
heartbeat_check in Python
monitor.maintenance-window
The scheduled maintenance window in force at a moment, if any, so alerts and uptime can be suppressed during it.
active_maintenance in Python
payroll.minimum-wage-check Unreviewed
Check pay for a pay reference period against the minimum or living wage for age and apprenticeship.
minimum_wage_check in Python
react.form.password-field React ^19 · TypeScript only
A password input with a Show/Hide button and an optional live checklist of a password policy (GOV.UK password input).
Not available in Python
monitor.heartbeat
Whether a cron job that pings on a schedule is new, up, late or down, from its last ping, period and grace time.
heartbeat_status in Python
text.normalise-name
Tidy a personal name: trim, collapse whitespace and title-case, with Mc, Mac, O', hyphen and van/de rules.
normalise_name in Python
legal.conflict-name-match Unreviewed
Fuzzy-match a name against existing clients and parties for a conflict check: normalised, token-sorted Jaro-Winkler.
conflict_name_match in Python