Chronos
χρόνος
Time you can measure: one hour after another, each with a rate attached. It’s what the timer counts and the ledger records, and tracking it well is honest work.
καιρός · the opportune moment
One ledger for your hours
and your agents’.
Kairos is a calm timer for client work. Track your hours by client and project, then build invoices from whatever you haven’t billed yet. Your AI assistant can use it too: Claude runs the timer, logs its own hours next to yours, and can tell you what’s unbilled and what’s been paid.
No credit card needed. Sign in with Google and you’ll be tracking time within a minute. Plans from $0.99 a month.Works with ChatGPT too: add the Kairos Timer plugin, or connect Claude, Cursor or any other MCP client.
Why the name
The Greeks had two words for time
Kairos
καιρός
The right moment. The sculptor Lysippos portrayed Kairos with a long forelock and a bald head behind: you can grab him as he approaches, but not once he has passed. Sending the invoice is that moment, and this app makes sure you catch it.
Timer
A timer that stays out of the way
In the cloth towns of the 1300s, a bell rang to open and close the working day. It was the first clock that answered to merchants rather than the church. Yours is a button. Pick a project, type what you’re working on and press start, then press stop when you’re done. You can always add a note later. You can also start and stop it from any browser tab with the Chrome extension.
The second pair of hands
Agents keep their own time
A journeyman was paid by the day (the journée), and the workshop’s ledger recorded his days alongside the master’s. The book didn’t care whose hands did the work, only that the hours were accurate. Connect Claude, ChatGPT, Cursor or any other MCP client and say “start on Northwind”, and the agent logs its own session against that client, in the same ledger as your hours and marked as its own. Setup takes about a minute: see the assistant guide.
It can read the ledger too. Ask how many hours the agent spent on the redesign, what’s still unbilled for a client, or whether last month’s invoice was paid, and it answers from your records instead of guessing.
You › “Start on Northwind, PR review.”
You › “Did Northwind pay the September invoice?”
Yes. Invoice #12 for Northwind — paid, $2,960.00.
“I use Kairos every day. Part of it is laziness: Claude starts the timer, so I don’t have to remember. But the bigger win is for my clients. The time is tracked to the minute instead of rounded up from memory, which saves them money, and every entry says what was actually done. They pay knowing what the hours bought.”
Your hours. Their hours. One ledger, and an invoice you can stand behind.
Invoices
Invoices built from unbilled time
For seven centuries, a debt was recorded on a notched stick split lengthwise. The lender kept one half (the stock), the borrower kept the other (the foil), and the debt was settled only when the two were matched. An invoice makes the same promise. Select the entries you want to bill, build the invoice, then print it or send it through Stripe. You can also ask your assistant whether it’s been paid.
Google Calendar
Meetings you forgot to track
Connect Google Calendar and today’s meetings show up as suggestions. One click turns a meeting into a time entry, so the time you forgot to track still makes it onto the invoice.
Teams
Weekly planning for a small team
Invite your team, see who’s working on what, and plan each project’s hours week by week. Everyone tracks their own time against shared clients, and it all rolls up into the same reports.
iPhone app
An iPhone app, coming soon
Coming soon to the App Store. Start and stop the timer from your phone when you’re away from your desk, even without a connection. Entries sync once you’re back online. Included with Pro.
Pricing
Just two plans
Basic is $0.99 a month for one person on the web. Pro is $1.99 a month and adds the iPhone app (coming soon) and room for up to 5 team members. These are founding prices, and the first 500 workspaces keep them for life.
Agents don’t count as seats.
Compare plansHow it works
From first hour to invoice in three steps
Every hour is priced at its project’s rate the moment you track it, so the totals are ready when it’s time to invoice.
I
Set up a client
Add a client, then a project with an hourly rate. Or import your existing customers from Stripe.
II
Track as you go
Ring the bell: start the timer when you begin work, or let your assistant ring it for you. Stop it when you’re done, and add a line about what you did.
III
Invoice what’s unbilled
Choose the entries and build the invoice. Print it, or send it through Stripe in one click. Catch the moment.
An old sundial motto: “I count only the sunny hours.” Kairos helps you count all of them.
Free for 14 days. Then from $0.99 a month.
Every workspace starts with a free 14-day trial of Pro. No credit card required, and you won’t be charged unless you pick a plan.
Get startedTry it without an account in a guest workspace. It’s deleted after 24 hours unless you sign in to keep it.