go-icalendar

Getting Started

Install

go get github.com/floatpane/go-icalendar

Requires Go 1.26+.

Parse an invite and render it

package main

import (
    "fmt"
    "log"
    "os"

    icalendar "github.com/floatpane/go-icalendar"
)

func main() {
    data, err := os.ReadFile("invite.ics")
    if err != nil {
        log.Fatal(err)
    }

    ev, err := icalendar.ParseICS(data)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("%s\n", ev.Summary)
    fmt.Printf("%s – %s\n", ev.Start.Local().Format("Mon Jan 2 3:04 PM"),
        ev.End.Local().Format("3:04 PM"))
    fmt.Printf("Organizer: %s\n", ev.Organizer)
    for _, a := range ev.Attendees {
        fmt.Printf("  %s (%s)\n", a.Email, a.PartStat)
    }
}

Reply to it

reply, err := icalendar.GenerateRSVP(data, "me@example.com", "ACCEPTED")
if err != nil {
    log.Fatal(err)
}
// Attach reply as text/calendar; method=REPLY and send it back to the organizer.

Send your own invite

start := time.Date(2026, 5, 1, 9, 0, 0, 0, time.UTC)
ev := &icalendar.Event{
    UID:       "kickoff-2026-05@example.com",
    Summary:   "Project kickoff",
    Location:  "Room 1",
    Start:     start,
    End:       start.Add(time.Hour),
    Organizer: "me@example.com",
    Attendees: []icalendar.Attendee{
        {Email: "you@example.com", PartStat: icalendar.PartStatNeedsAction, RSVP: true},
    },
}
ics, err := icalendar.NewRequest(ev).Serialize()

Where next