Frothly Time

Exact time

Synchronizing

From Frothly’s stratum-1 clocks, each steered to UTC by GPS and held by a rubidium oscillator when the sky goes quiet, and corrected for the time it takes to reach you.

Coordinated Universal Time

Your device says

Measuring…

The world, right now

Daylight, twilight and night, redrawn every minute · nautical time zones

  • Day
  • Civil twilight
  • Nautical twilight
  • Night
  • The sun overhead
  • Frothly time server

  • San Francisco

    Headquarters

  • Chiba

    Glossia office

  • Reykjavík

    Time server

  • UTC

    Universal

Time scales

The same instant, counted six ways

UTC
Civil time worldwide
TAI
Atomic time · UTC + 37 s
GPS
Satellite time · UTC + 18 s
Unix
Seconds since 1970
Modified Julian Date
Days since 17 Nov 1858
Day of year
ISO week, in UTC

Our servers

Offsets are the worst seen in the past 24 hours

ServerLocationReferenceOffsetStatus
sfo.time.frothly.org San Francisco GPS, rubidium holdover ±0.000 017 s Serving
chb.time.frothly.org Chiba GPS and QZSS, rubidium holdover ±0.000 014 s Serving
rkv.time.frothly.org Reykjavík Galileo and GPS, rubidium holdover ±0.000 021 s Serving

Why a research institute keeps time

Almost every promise we make is a promise about time: that a message is fresh, that a certificate is still valid, that a record existed on the day we say it did. Ordinary network time is unauthenticated, so anyone between you and your clock can lie about it. We run authenticated time for our own networks, and for anyone else who wants it.

  • Glossia

    Relays that can’t be rewound

    Relays only trust a directory inside its validity window. Wind a relay’s clock back and it will accept an expired list of relays chosen by whoever moved its clock.

  • LoTek

    Nodes with no clock of their own

    Our mesh routers have no battery-backed clock. Each one wakes up believing it is 1970, and can’t check a single certificate until the network tells it the date.

  • Lazarus and the Registry

    Dates that hold up in court

    Every archive capture and Registry entry carries a signed timestamp from our time authority, so the date on it can still be checked when the people who made it are long gone.

Use our time

Free for anyone, no account needed. Network Time Security (RFC 8915) proves each answer came from us and wasn’t altered on the way. Never trust a single clock, ours included: give your computer a second, independent source as well.

# /etc/chrony/chrony.conf
server time.frothly.org iburst nts
# a second, independent source
server time.cloudflare.com iburst nts

# Roughtime
roughtime.frothly.org:2002
# public key (Ed25519)
6v4fpi/TugWHOuyOcuHS4tw/z3xXcy2jxyXTcNiqMS8=

A web page can only show the time to within a few hundredths of a second, because the answer has to cross the internet to reach you. We measure that trip and correct for it, and the figure next to “Synchronized” is how sure we are. For anything more precise, point your computer at our servers directly.