λ

// haskell.day 2026 :: Annual Celebration

A day of
pure functions.

main :: IO Celebration

June 14, 2026  ·  Reykjavík + worldwide stream  ·  24 talks · 12 hours · 1 lambda

schedule :: [Talk]

The Day

speakers :: { name :: Text, talk :: Text }

Voices

AL

Astrid Lindberg

type theorist, kindred of HoTT

MO

Mosi Okonkwo

algebraic effects, free monads

YT

Yuki Tanaka

category-theoretic compilers

SM

Sigrid Marlow

GHC core team

JC

Jules Cardelli

streaming abstractions

RP

Renzo Park

dependent types in practice

venue :: Maybe Place

Where

Harpa Concert Hall, Reykjavík

A glass honeycomb on the North Atlantic. Doors at 08:30. Lightning track in foyer C.

Live mirror :: stream.haskell.day   ·   chat :: #haskell-day

64.1500° N  ·  21.9333° W

community :: m (m (m Person))

Nested

A celebration is monadic: each layer wraps the last, propagating context. Sponsors hold organizers, organizers hold speakers, speakers hold attendees, attendees hold the room.

Sponsors
Organizers
Speakers
Attendees
return ()

register :: Email -> IO Ticket

IO ()

No ticketing forms here. Send a curl-shaped greeting, get a confirmation by return.

-- in your shell
curl -X POST haskell.day/api/register \
  -d '{"email":"you@domain"}'

IO awaits.

tracks :: Sum Track

Tracks

program :: Attendee -> IO Memory

Composition Pipeline

01 register :: IO Ticket

Sign up with one curl. We send you a typed ticket.

|>
02 attend :: Ticket -> IO Seat

Arrive in Reykjavík or join the stream. Coffee, seat, breath.

|>
03 learn :: Seat -> IO Insight

Twelve hours of talks, demos, hallway proofs.

|>
04 contribute :: Insight -> IO ()

PR the community. Lightning talks, mentoring, sponsorships.

manifesto :: Text

Why we gather

Because purity is generous: it lets us reason about what we built without re-running the world.

Because types are notes from the future, telling the present what is possible.

Because composition is the simplest political act: smaller things forming larger ones, without asking permission.

Because once a year, the lambda needs a holiday.