typikon

The Orthodox liturgical day: feasts, seasons and the fast, computed rather than fetched.

Everything derives from the paschalion and the fixed calendar, so it needs no network, cannot go stale, and answers for any year you ask about. No API key, no service that might be gone next year, no cache to invalidate.

$ typikon
  Wednesday 18 March 2026   — 5 March in the church calendar
  Russian Orthodox Church Outside Russia · the Typikon

  🥬  The Holy Martyr Conon

      xerophagy — no oil or wine
      a weekday of the Great Fast
      Great Fast

Install

One static binary, no runtime to install first.

$ cargo install --git https://git.pumpin.online/funkpower/typikon

Or build it from a checkout:

$ git clone https://git.pumpin.online/funkpower/typikon
$ cd typikon && cargo build --release
$ install -Dm755 target/release/typikon ~/.local/bin/typikon

The menologion is compiled in, so the binary answers for every day of the year on its own: no data file to find, no network, nothing to go stale.

Which calendar?

Three things get conflated constantly, and keeping them apart is most of what this library is for:

Paschalion	which table gives Pascha, Julian or Gregorian
Menologion	which calendar the fixed feasts are read on
Rule	which fasting discipline is kept

Almost every Orthodox Church keeps the Julian Paschalion. What divides them is the menologion. The old-calendar churches read the fixed feasts on the Julian calendar too; the new-calendar churches read them on the Revised Julian, which agrees with the Gregorian for every date until 2800. So a new-calendar church keeps the Nativity with the West and Pascha with the East, not a compromise but exactly what the 1923 congress decided.

Pick a reckoning without naming a church:

$ typikon --calendar old        # Julian throughout
$ typikon --calendar new        # Revised Julian fixed feasts, Julian Pascha
$ typikon --calendar western    # Gregorian throughout

Or name one, which also picks up its fasting rule and any local saints:

$ typikon --jurisdiction rocor
$ typikon --jurisdiction antiochian --days 7
$ typikon --list                # every accepted value

The first run writes your choice to ~/.config/typikon/config.toml and stops asking. Change it with --set-default, override it for one run with the flag, or set TYPIKON_JURISDICTION.

Twenty-three jurisdictions ship: the old-calendar churches (Moscow, ROCOR, Serbia, Georgia, Jerusalem, the Holy Mountain, Poland, Macedonia), the new-calendar ones (Constantinople, Greece, GOARCH, Antioch, the OCA, Romania, Bulgaria, Cyprus, Albania, Ukraine), the Finnish Orthodox Church, alone among the Orthodox in keeping the Gregorian Paschalion, and, as an add-on, four Byzantine Catholic churches.

The fast

Six levels, ordered from strictest to laxest. They are the Typikon's own distinctions, not a simplification of them:

strict	no food until evening
xerophagy	no oil, no wine; no meat, fish, eggs or dairy
wine_oil	wine and oil permitted
fish	fish, wine and oil permitted
dairy	dairy, eggs and fish permitted; no meat
none	no fast

A calendar that reports xerophagy and wine-and-oil both as "fasting" has thrown away the information its reader wanted.

Level and obligation are separate questions. The Orthodox Church legislates fasting as tradition rather than as precept, so every Orthodox day here reports as customary. The Eastern Catholic churches do have law about it, and it requires very much less than the Typikon describes, so those jurisdictions report both the level at which the day is kept and the minimum that actually binds. A calendar saying "obligatory" where nothing obliges is worse than no calendar; one reporting only the binding minimum makes the obligatory days look laxer than the voluntary ones beside them.

Where usages differ (Great Thursday, the Exaltation, Lazarus Saturday), this follows the common published rule and names it in the day's reason so you can disagree with it. Monastic practice, and the Holy Mountain in particular, is stricter than all of it. A calendar cannot settle that; your bishop and your spiritual father can.

Output

$ typikon --json --days 7        # for a bar, a widget, a script
$ typikon --ics --days 365 > orthodox.ics
$ typikon --year 2027            # a year's key dates, to check against yours

The JSON shape is flat and stable. Front ends are the thing most likely to be written by someone else, and a schema that shifts underneath them is a bad neighbour.

As a library

use typikon::calendars::Date;
use typikon::day::describe;
use typikon::jurisdictions::resolve;

let rocor = resolve(Some("rocor"))?;
let day = describe(Date::from_ymd(2026, 9, 18).unwrap(), rocor);

day.church_date;     // "5 September"
day.fast;            // Level::Xerophagy
day.title();         // "The Holy Prophet Zachariah, father of the Forerunner"
day.is_obligatory(); // false

typikon::paschalion::julian_pascha(2027);     // 2027-05-02
typikon::paschalion::gregorian_pascha(2027);  // 2027-03-28

The levels are an ordered enum, strictest first, so a < b reads as "a is stricter than b" and a feast can only ever relax a fast:

Level::Xerophagy.relaxed_to(Level::Fish, Level::WineOil)  // WineOil: no saint
                                                          // brings fish into Lent
Level::Fish.relaxed_to(Level::WineOil, Level::WineOil)    // Fish: never tightens

The menologion

The fixed calendar ships as data and is indexed by ecclesiastical date, so one file serves every jurisdiction. An old-calendar church and a new-calendar church both keep the Nativity on 25 December; they disagree about which morning that is, and that disagreement lives in the calendar conversion, not in the data.

data/menologion.json, compiled into the binary, covers all 366 days with the principal commemorations of the common Byzantine tradition, ranked so the fasting rules know when a feast lifts a Wednesday. It was composed for this project and is under the same licence as the code. It is a working set, not a complete Synaxarion; additions are welcome.

Some churches also keep their own saints, and those lists are usually published by a body that holds the copyright in the wording. Those are not shipped. Fetch one onto your own machine instead:

$ typikon --list-menaia
$ typikon --update-menaion ruthenian

It lands in ~/.local/share/typikon/ and is overlaid automatically.

Accuracy

typikon is pinned against published calendars: the paschalion for six years by both reckonings and its invariants across two centuries, 146,000 calendar round-trips from 1800 to 2200, the fast on every day that is not open to interpretation, and every jurisdiction over twenty years.

It was ported from a Python implementation, and the port was checked by running both over 199,446 day-records, 26 jurisdictions across 21 years, and requiring every field of every record to match.

It is a calendar, not an authority. If it disagrees with the one your parish prints, your parish is right. Please open an issue.

Front ends

menologion: desktop widgets for Hyprland (Quickshell), waybar and eww, all reading the JSON above.

Licence

GPL-2.0-only. See LICENSE. The menologion is under it too; data/LICENSE says so and notes what the fetched sets are not.