OpenChronology Reference Implementation
Author events in the open .chron format. Explore timelines spanning centuries. Share your record of history — freely, permanently, in a format that will outlast any platform.
Author events, calendars, and universes. Visualize, validate, package, and convert. Everything for your chronological data — no lock-in, no code required.
A guided form for crafting .chron files. No schema knowledge required — fill in what you know and export a valid, independently-citable event file in seconds. Every field beyond the title is optional.
Not one viewer, but many — Horizon, Codex, Ledger, and Gantt. Each renders the same .chron data differently. Drag in your files and explore. The standard is renderer-agnostic.
Paste or drop any .chron, .chroncal, .chronverse, or .chronpkg file and get instant schema feedback. Four severity levels. Exportable report.
Pack a collection of .chron files into a portable .chronpkg bundle — or unpack an existing bundle to inspect its events. Drag-and-drop interface, manifest preview, no code required.
Define a custom calendar system and export a .chroncal file. Name your months, set your epoch, describe your year length and intercalation rules. Reusable across any .chron file that references it.
Define a fictional or alternative universe and export a .chronverse file — canon scope, physics anchors, timeline frame. Built for novelists, game designers, and worldbuilders who need structured, shareable lore.
Import timelines from the formats you already have. Drop in an .ics, .ical, TimelineJS, CSV, KML, GEDCOM, or Wikidata export and receive clean, structured .chron files ready for any OpenChronology tool.
The OpenChronology standard defines how events are stored, not how they are displayed. These four conceptual implementations show the range of experiences possible from the same .chron data — each a different answer to the same question.
Horizon
The classic. A horizontal axis with significance-scaled dots and alternating above/below labels. Ideal for historical spans.
Codex
Vertical narrative. Events unfold like pages in a book — a natural fit for biography, story arcs, and sequential history.
Ledger
Tabular and data-forward. Sortable, filterable, dense. Built for researchers who need the full record at a glance.
Gantt
Duration-first. Eras as bars, events as milestones. Built for project timelines, overlapping epochs, and anything with a start and an end.
All four viewers are live and free to use. Drag in any .chron files and explore. Visit the Timeline Viewer Gallery to open them, or find community-built implementations at openchronology.org/libraries. The standard is open; the ecosystem belongs to everyone.
Chronology Studio is one reference implementation of the OpenChronology specification. Every .chron file you create is portable, independently citable, and readable by any conforming tool — today, and for as long as JSON endures.
The 1000 Year Project — anchoring OpenChronology at 1000yearproject.org — serves as the featured demonstration dataset for Chronology Studio. History from 1000 to 2000 CE, structured in open .chron format, with significance levels from local milestones to civilizational events.
Chronology Studio is under active development. Leave your email and we'll notify you when the first tools are ready to use.
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