v0.2.0

Complete rewrite. Breaking changes throughout — not compatible with 0.1.x.

What's new

• All four HMRC rate series, not just monthly: monthly customs/VAT, spot, yearly average, and the discontinued 2014-2016 weekly amendments, all through one Rates value.
• Deeper history: monthly back to 2014-02 (150 months), spot and average back to Dec 2010 (32 periods each, years ending 31 Mar / 31 Dec), backfilled from the UK Government Web Archive.
• Zero-cost bundling: the full dataset compiles into static tables at build time — Rates::new() is free and infallible, no parsing or I/O at startup.
• Exact arithmetic, strict lookups: conversions use rust_decimal and are never rounded; an unpublished period is always an error, never a silently substituted older rate. An explicit, opt-in fallback (monthly_rate_or_earlier) is available when you want it.
• Optional live updates (http feature): a blocking Updater fetches newly published periods from the Trade Tariff API, with a verbatim on-disk cache.
• no_std + alloc core: builds on wasm32-unknown-unknown with just the bundled feature.
• serde feature for compact string forms ("2026-07", "USD", "monthly").
• Optional CLI (cli feature): hmrc-rates convert, rate, list, currencies.
• CI now checks for new HMRC rates daily and auto-releases patch versions.

Example

use hmrc_rates::{Month, Rates, YearEnd};
use rust_decimal::Decimal;

let rates = Rates::new();
let rate = rates.monthly_rate("USD", Month::new(2025, 8).unwrap())?;
println!("{}", rate.to_gbp(Decimal::from(2500)).round_dp(2)); // £1846.24

let eur = rates.average(YearEnd::march(2025))?.rate("EUR")?;
println!("{}", eur.units_per_gbp()); // 1.1880

Coverage

Series	Range
Monthly	2014-02 - present
Spot	Dec 2010 - present (31 Mar / 31 Dec)
Yearly average	Dec 2010 - present (31 Mar / 31 Dec)
Weekly amendments	2014-01-08 - 2016-04-27 (discontinued)

Full details: README · data sources · API docs

MSRV 1.85 · MIT