Suites · charity
Charity and fundraising
Donations for a UK charity: Gift Aid eligibility and claims, small donations, regular giving schedules, matched giving, payroll giving and restricted fund accounting.
62 capabilities (26 core, 36 optional) and 13 gaps, in build order. Put each line in the file that calls it, then fune build.
UK only: Gift Aid, GASDS and Payroll Giving follow HMRC's rules for charities; this is not tax advice.
TypeScript Python Rust
1. Donations and Gift Aid
Take donations and work out the Gift Aid each one can add.
charity.gift-aid-eligibility core
Whether a donation qualifies: a declaration, enough tax paid, and the donor benefit limits.
Whether a UK donation qualifies for Gift Aid: declaration, enough tax paid, and the donor benefit limits.
from fune.charity.gift_aid_eligibility import gift_aid_eligibility # charity.gift-aid-eligibility@^1
1.0.2
charity.gift-aid core
Gift Aid the charity can claim on a donation: 25p per £1 at the basic rate.
Gift Aid a UK charity can claim on a donation: basic rate tax grossed up, 25p per £1 at 20%.
from fune.charity.gift_aid import gift_aid # charity.gift-aid@^1
1.0.2
charity.donation-matching optional
Employer match on a donation: a ratio limited by a per-donor cap and a programme budget.
Employer match on a donation: a ratio in basis points, limited by a per-donor cap and a programme budget.
from fune.charity.donation_matching import donation_match # charity.donation-matching@^1
1.0.0
charity.higher-rate-relief optional
The extra relief a higher-rate donor can claim, to tell them about it.
A Gift Aid donor's extra tax relief at higher, intermediate, additional and top rates, by extending the tax bands.
from fune.charity.higher_rate_relief import higher_rate_relief # charity.higher-rate-relief@^1
1.0.0
declarations Capturing and storing Gift Aid declarations (wording, date, cancellation) as HMRC requires.online-payments Taking card or Direct Debit donations through a provider, and their webhooks.
2. Regular giving
Collect monthly, quarterly or annual gifts on time.
charity.regular-giving-schedule core
Collection dates for a regular gift, clamped to short months, after a lead time.
Collection dates for a regular gift: monthly, quarterly or annual on a day, clamped to short months, after a lead time.
from fune.charity.regular_giving_schedule import regular_giving_schedule # charity.regular-giving-schedule@^1
1.0.0
charity.payroll-giving optional
Payroll Giving: the donation comes off pay before PAYE, and the tax it saves.
UK Payroll Giving for one pay period: the donation comes off pay before PAYE, and the tax it saves the employee.
from fune.charity.payroll_giving import payroll_giving # charity.payroll-giving@^1
1.0.0
3. Gift Aid claims
Reclaim tax from HMRC for a period.
charity.reclaim-batch core
Claim totals for a period from donation records: donor lines, aggregated small gifts, tax due, and what was left out.
Gift Aid claim totals for a period from donation records: donor lines, aggregated small gifts, tax due.
from fune.charity.reclaim_batch import gift_aid_claim_batch # charity.reclaim-batch@^1
1.0.1
charity.gasds optional
Gift Aid Small Donations Scheme top-up for a tax year, within the £8,000 limit.
Gift Aid Small Donations Scheme top-up for a tax year: the £8,000 limit, the matching rule and community buildings.
from fune.charity.gasds import gasds # charity.gasds@^1
1.0.2
dates.uk-tax-year optional
Which tax year a donation falls in, for claims and GASDS limits.
The UK personal tax year containing a date: 6 April to 5 April, with HMRC's label.
from fune.dates.uk_tax_year import uk_tax_year # dates.uk-tax-year@^1
1.0.0
charities-online Submitting the claim to HMRC through Charities Online (the XML schedule and the gateway).
4. Funds and reporting
Spend restricted money only on what it was given for, and report on fundraising.
charity.restricted-funds core
Allocates spending to restricted funds first, then unrestricted, never overdrawing a restricted fund.
Allocate charity spending to restricted funds first, then unrestricted funds, never overdrawing a restricted fund.
from fune.charity.restricted_funds import allocate_fund_spend # charity.restricted-funds@^1
1.0.0
charity.fundraising-ratio optional
Cost to raise £1 and the charitable spend ratio.
Cost to raise £1 and charitable spend ratio for a charity, in exact basis points.
from fune.charity.fundraising_ratio import fundraising_ratios # charity.fundraising-ratio@^1
1.0.0
sorp-accounts Annual accounts in the Charities SORP format and the trustees' report.
Hold money as currency-tagged integer minor units and do plain arithmetic on it safely.
money.amount core
The Money type ({ minor, currency }) every other money capability takes and returns.
A currency-tagged monetary amount held in integer minor units.
from fune.money.amount import money # money.amount@^1
1.0.2
money.add core
Adds and subtracts amounts, refusing to mix currencies by accident.
Add, subtract and negate monetary amounts, refusing to mix currencies.
from fune.money.add import add_money # money.add@^1
1.0.1
money.sum core
Totals a list of amounts, with an explicit currency for an empty list.
Total a list of monetary amounts, with an explicit currency for the empty case.
from fune.money.sum import sum_money # money.sum@^1
1.0.1
money.compare core
Compares, mins, maxes and clamps amounts of one currency without unwrapping them.
Compare two amounts of one currency, refusing to compare across currencies; min, max and clamp too.
from fune.money.compare import compare_money, min_money, max_money, clamp_money # money.compare@^2
2.0.04 functions
6. Rates and rounding from money-basics
Apply percentages and divide amounts with the rounding stated, never a float.
money.apply-rate core
Applies a basis-point rate (VAT, discount, commission) to an amount with explicit rounding.
Apply a rate expressed in basis points to a monetary amount, with an explicit rounding mode.
from fune.money.apply_rate import apply_rate # money.apply-rate@^1
1.0.1
math.round-div core
Integer division with a named rounding mode, for any money maths the others do not cover.
Integer division with an explicit rounding mode, for money arithmetic that must not drift.
from fune.math.round_div import round_div # math.round-div@^1
1.0.0
math.basis-points optional
Converts "12.5%" to and from basis points exactly, for rates typed in by users.
Convert a rate between percent, basis points and a plain ratio exactly, as decimal text or integer basis points.
from fune.math.basis_points import convert_rate, to_basis_points, from_basis_points # math.basis-points@^2
2.0.03 functions
math.percent-change optional
Percentage change between two figures in basis points, for "up 4.2% on last month".
Percentage change from one value to another, in basis points, with an explicit rounding mode.
from fune.math.percent_change import percent_change # math.percent-change@^1
1.0.0
math.rational optional
Exact fractions for rates that must not drift across many steps.
Exact fraction arithmetic, always reduced, for rates and ratios that must not drift.
from fune.math.rational import calculate_rational, rational, add_rational, subtract_rational, multiply_rational, divide_rational, compare_rational, rational_to_integer # math.rational@^2
2.0.08 functions
math.round-div-big optional
Rounded division on numbers past 2^53, for very large totals.
Divide two integers of any size with an explicit rounding mode, on decimal strings, for exact money sums past 2^53.
from fune.math.round_div_big import round_div_big # math.round-div-big@^1
1.0.0
Divide an amount between people, periods or lines so the parts add back to the whole.
money.allocate core
Splits an amount by ratios (60/40, by quantity) without losing or inventing a penny.
Split an amount across ratios without losing or inventing a single minor unit.
from fune.money.allocate import allocate # money.allocate@^1
1.0.1
money.split-even optional
Splits an amount into n near-equal parts that sum exactly, for instalments or shares.
Split an amount into n near-equal parts that add back up to exactly the whole.
from fune.money.split_even import split_even # money.split-even@^1
1.0.0
8. Display and input from money-basics
Show amounts to people and read what they type.
money.format core
Renders an amount as text with the currency's real number of decimal places.
Render a monetary amount as text, using the currency's real minor-unit precision.
from fune.money.format import format_money # money.format@^1
1.0.0
money.parse optional
Reads "£1,234.50" or "1.234,50 €" typed by a user into minor units, strictly.
Parse "£1,234.50" or "1.234,50 €" into integer minor units, strictly: no guessing, no rounding.
from fune.money.parse import parse_money # money.parse@^1
1.0.0
money.currency-digits optional
How many decimal places each ISO 4217 currency has, for input boxes and validation.
How many decimal places a currency's minor unit has, from the ISO 4217 list.
from fune.money.currency_digits import currency_digits # money.currency-digits@^1
1.0.0
9. Other currencies from money-basics
Convert between currencies at a rate you hold.
money.convert optional
Converts an amount at a supplied exact rate with explicit rounding.
Convert an amount to another currency at a supplied exact rate, with an explicit rounding mode.
from fune.money.convert import convert_money # money.convert@^1
1.0.0
10. Calendar arithmetic from dates-basics
Move and measure ISO dates exactly, with no date library and no clock reads.
dates.add-days core
Shifts a date by whole days, for due dates and windows.
Shift an ISO date by a whole number of days, forwards or backwards, with exact calendar arithmetic.
from fune.dates.add_days import add_days # dates.add-days@^1
1.0.0
dates.add-months core
Adds months clamping to month end, so 31 January plus a month is the end of February.
Add calendar months to an ISO date, clamping to the month end: 31 Jan + 1 month is 28 or 29 Feb.
from fune.dates.add_months import add_months # dates.add-months@^1
1.0.0
dates.days-between core
Signed calendar days between two dates, for ages of invoices and stays.
Calendar days from one ISO date to another, signed: negative when the second date is earlier.
from fune.dates.days_between import days_between # dates.days-between@^1
1.0.0
dates.month-boundaries core
First and last day of a date's month, for monthly periods and statements.
The first day, last day and length of the calendar month containing a date.
from fune.dates.month_boundaries import month_boundaries # dates.month-boundaries@^1
1.0.0
dates.day-of-week core
ISO weekday of a date, for weekend rules and opening hours.
The ISO 8601 day of the week for a date: 1 is Monday through 7 is Sunday.
from fune.dates.day_of_week import day_of_week # dates.day-of-week@^1
1.0.0
dates.is-leap-year optional
Whether a year is a leap year, for 365/366-day calculations.
Whether a year is a Gregorian leap year: every 4th, except centuries, except every 400th.
from fune.dates.is_leap_year import is_leap_year # dates.is-leap-year@^1
1.0.0
dates.overlap optional
Days two date ranges share, for prorating and clash checks.
Days two date ranges have in common, with the end of each range stated as inclusive or exclusive.
from fune.dates.overlap import overlap_days # dates.overlap@^1
1.0.0
dates.age optional
Age in whole years on a date, handling 29 February birthdays.
Age in whole years on a given date, with 29 February birthdays ageing on 1 March in other years.
from fune.dates.age import age # dates.age@^1
1.0.0
11. Periods and reporting dates from dates-basics
Put dates into the periods reports are grouped by.
dates.quarter core
Calendar and fiscal quarter of a date for any year-start month.
Calendar quarter and fiscal quarter of a date, with the fiscal year and quarter date ranges, for any start month.
from fune.dates.quarter import quarter # dates.quarter@^1
1.0.0
dates.week-number optional
ISO week number and week-year, for weekly reports.
ISO 8601 week number and week-numbering year of a date: weeks start Monday, week 1 holds the first Thursday.
from fune.dates.week_number import week_number # dates.week-number@^1
1.0.0
dates.day-count-fraction optional
Year fraction by ACT/365F, ACT/360, 30/360 or ACT/ACT, for interest periods.
Year fraction between two dates by ACT/365F, ACT/360, 30/360, 30E/360 or ACT/ACT ISDA, as an exact fraction.
from fune.dates.day_count_fraction import day_count_fraction # dates.day-count-fraction@^1
1.0.0
12. Working days and holidays from dates-basics
Skip weekends and public holidays when counting or adding days.
dates.bank-holidays core
UK bank holidays for a region and year, as gov.uk publishes them.
UK bank and public holidays for a region and year, as published by gov.uk, including one-off holidays.
from fune.dates.bank_holidays import bank_holidays # dates.bank-holidays@^1
1.0.1
dates.add-business-days core
Moves a date by working days, skipping weekends and a holiday list.
Move a date forward or back by working days, skipping weekends and a caller-supplied holiday list.
from fune.dates.add_business_days import add_business_days # dates.add-business-days@^1
1.0.0
dates.business-days-between core
Working days between two dates, for SLAs and notice periods.
Working days between two dates, excluding weekends and a caller-supplied holiday list.
from fune.dates.business_days_between import business_days_between # dates.business-days-between@^1
1.0.0
13. Repeating schedules from dates-basics
Generate the dates of something that repeats.
dates.recurrence optional
The next n dates of a rule: monthly on the 31st, last Friday, every two weeks.
The next n dates of a repeating rule: monthly on a day, last weekday of the month, every k days or weeks, yearly.
from fune.dates.recurrence import recurrence # dates.recurrence@^1
1.0.0
14. Times and durations from dates-basics
Work with times of day, durations and timestamps.
time.duration optional
Parses and adds durations like 1h30m in whole minutes, and formats the total.
Parse durations written as 1h30m, 90m or 01:30, add them up in whole minutes, and format the total.
from fune.time.duration import duration # time.duration@^1
1.0.0
time.minutes-between optional
Minutes between two local date-times, across midnight.
Minutes from one local date and time to another, correct across midnight; wall-clock time, no time zones.
from fune.time.minutes_between import minutes_between # time.minutes-between@^1
1.0.0
time.round-to-increment optional
Rounds minutes to a billing increment such as 6 or 15.
Round a duration in minutes to a billing increment such as 6 or 15 minutes, up, down or to nearest.
from fune.time.round_to_increment import round_to_increment # time.round-to-increment@^1
1.0.0
time.iso-to-unix optional
RFC 3339 timestamps to Unix seconds.
An RFC 3339 timestamp with a Z or offset, such as 2026-09-26T13:00:00+01:00, to Unix time in whole seconds.
from fune.time.iso_to_unix import iso_to_unix # time.iso-to-unix@^1
1.0.0
time.unix-to-iso optional
Unix seconds to an ISO 8601 UTC timestamp.
Unix time in seconds to an ISO 8601 UTC timestamp such as 2026-09-26T12:00:00Z, for years 0001 to 9999.
from fune.time.unix_to_iso import unix_to_iso # time.unix-to-iso@^1
1.0.0
time.countdown optional
Seconds left until a moment and a 4:05 style timer text.
Seconds left until a Unix time, whether it has passed, and a timer text like 4:05, for tokens or retry waits.
from fune.time.countdown import countdown # time.countdown@^1
1.0.0
Check payee and customer bank details before money moves.
validation.iban core
Checks an IBAN's mod-97 checksum and its country's length.
Check an IBAN against the ISO 13616 mod-97-10 checksum and the registered length for its country.
from fune.validation.iban import is_iban # validation.iban@^1
1.0.0
validation.bic optional
Checks a SWIFT/BIC code's format and splits it.
Check the format of a SWIFT/BIC code (8 or 11 characters) and split it into its parts.
from fune.validation.bic import validate_bic # validation.bic@^1
1.0.0
validation.uk-sort-code-account optional
Checks a UK sort code and account number by the Vocalink modulus rules, against a table you supply.
Check a UK sort code and account number with the Vocalink/Pay.UK modulus rules, against a table you supply.
from fune.validation.uk_sort_code_account import validate_uk_sort_code_account # validation.uk-sort-code-account@^3
3.0.0
validation.uk-modulus-table optional
Parses Vocalink's VALACDOS and SCSUBTAB files into that table.
Parse Vocalink's VALACDOS.txt and SCSUBTAB.txt into the table UK sort code modulus checking needs.
from fune.validation.uk_modulus_table import parse_uk_modulus_table # validation.uk-modulus-table@^1
1.0.0
17. Identifiers and check digits from validation-basics
Catch mistyped reference numbers by their check digits.
validation.luhn optional
Luhn mod-10 check, for card numbers and many reference numbers.
Check a digit string against the Luhn mod-10 checksum used by payment cards and many identifiers.
from fune.validation.luhn import is_luhn # validation.luhn@^1
1.0.0
validation.uk-company-number optional
Checks a Companies House number's format and prefix.
Check a Companies House company number's format and prefix (SC, NI, OC, LP...) and zero-pad it to eight characters.
from fune.validation.uk_company_number import validate_uk_company_number # validation.uk-company-number@^2
2.0.1
validation.lei optional
Checks a Legal Entity Identifier's check digits.
Check a 20-character Legal Entity Identifier against its ISO 17442 / ISO 7064 MOD 97-10 check digits.
from fune.validation.lei import validate_lei # validation.lei@^1
1.0.0
validation.gtin optional
Checks an EAN/UPC/GTIN barcode number.
Check an EAN-8, UPC-A, EAN-13 or GTIN-14 barcode number against the GS1 mod-10 check digit.
from fune.validation.gtin import validate_gtin # validation.gtin@^1
1.1.0
18. Displaying sensitive values from validation-basics
Show stored identifiers without exposing them.
text.mask optional
Masks all but the last digits of a card, account or phone number.
Mask all but the last n characters of a card, account or phone number, optionally keeping separators.
from fune.text.mask import mask # text.mask@^1
1.0.0
Gaps What this kind of app usually needs that Functional Weave does not have yet: write these yourself, or use a service.
donor-consent Donor marketing consent and preferences under GDPR and the Fundraising Regulator's code.fx-rate-source Where exchange rates come from: money.convert takes a rate you supply; fetching and storing daily rates (ECB, a provider's API) is yours.money-storage Storing amounts: the database columns (integer minor units plus a currency code) and their migrations are yours.time-zones Time zones and daylight saving: caps works in ISO dates, UTC and wall-clock times; converting with the IANA tz rules is yours.locale-formatting Showing dates in a user's language and format ("3 octobre 2026"): caps returns ISO dates, not localised text.non-uk-holidays Public holidays outside the UK: dates.bank-holidays is UK only; pass another country's list to the working-day functions yourself.address-lookup Turning a postcode into a list of addresses (Royal Mail PAF or a lookup API) is network work and not in caps.email-deliverability Whether a mailbox exists (MX lookups, a confirmation email): validation.email checks the syntax only.vocalink-data The Vocalink modulus tables themselves: download them from Pay.UK under its terms; caps parses them but does not ship them.