Owl + Kestrel · Selected work
Owl + Kestrel

Portfolio

Selected work.

We design, build and run websites, web apps and the software behind them. Start with Circadia, our own app, then the websites and the workflows you can try.

Case study

Designed, built and run by Owl + Kestrel
Case study · our own web app

Circadia

Some days are 25 hours long.

Circadia is a free sleep tracker for Non-24, Delayed Sleep Phase and other circadian rhythm disorders. We design, build and run it, and it has been open to everyone at circadia.owlandkestrel.com since May 13, 2026.

Circadia: a hand-drawn moon above the headline Some days are 25 hours long

The problem

Sleep apps assume a 24-hour day. For people whose body runs on a longer day, a later one, or no steady one at all, a bedtime reminder at eleven is noise. Circadia's founder has Non-24: “I wanted an app that would let me type in my own sleep and tell me when the next one was coming. None of the ones I tried could do either. So I built one.”

What we built

Two taps a day, Sleep Now and Wake Now. From that log Circadia works out the drift and τ, the real length of your day, with more than one estimator and a confidence tier so a number never looks surer than it is. It draws the actogram sleep labs use, forecasts the next sleep windows with two models and grades every forecast afterward against the sleep that happened. A Doctor’s Report PDF gives a clinic a read-only, revocable 90-day view.

How it runs

A web app that installs to a phone: no download, no card. The log stays on the device until you sign in, then syncs across your devices. Twelve import sources, full export and delete. The Adaptive forecast is statistical modelling; there are no generative-AI features, no ads and no tracking in the app.

Built with the people using it

Most of what is in Circadia came from its users: they find the bugs, vote on what comes next and, if they choose, share their logs for research. Sharing is off until each person picks a level, and it can be revoked.

Open since
May 13, 2026
Made for
Non-24, delayed and advanced sleep phase, ME/CFS, shift work
Price
Free core app; optional Circadia Plus subscription
Published cohort
256 sign-ups and 118 people sharing data, as of October 27, 2026
Team
Two people
Circadia's log screen: 86 sleeps, average drift of 36 minutes, a Sleep Now button and recent nights each starting later
Log · example data
Circadia's rhythm screen: drifting 33 minutes later each day, a 24.6-hour body day and a 30-day sleep chart climbing like a staircase
Rhythm · example data
Circadia's forecast screen: the next sleep at 12:21 am, an Event Check button and predicted sleep windows for the coming nights
Forecast · example data
Open Circadia Product page How the forecasts are measured

Websites

Design and frontend

The businesses, places and data in these websites and the workflow below are made up for the work. None is a client endorsement, and no business results are claimed.

Ground website: a terraced garden photograph above the headline Good yards start with the ground Websites · interactive frontend

Ground + Canopy

Two landscape company websites with distinct art direction and interactive details. Inquiry and estimate forms are simulated; nothing is sent.

Open the website gallery
Alder Vale Piano website: editorial type beside an isometric keyboard drawing Website · interactive frontend · PDF

Alder Vale Piano

A piano care and restoration studio's site, with original vector studies. The inquiry form works locally only; nothing is sent.

Browse the site Presentation PDF
Nimbrel website: a dark product page about two independent relays Website · interactive frontend

Nimbrel

A privacy-network brand site built around one rule: neither relay sees both who you are and where you go. Signup is simulated; nothing is sent.

Browse the site
Commonlight presentation PDF: two identity directions, palette and type Identity and website design · PDF

Commonlight

An identity and homepage for a collective of community funds: two mark directions, a small colour and type system, and desktop and mobile layouts.

Open the PDF
Common Ground website: a community fund's homepage with an Edit this page control Website · interactive frontend

Common Ground

A community initiative's site with responsive navigation and a page editor. Edits are saved in this browser only; nothing is published or sent.

Browse the site

Software

Workflow and product design
Inquiry desk: a landscaping company's estimate request form beside the CRM records and team alerts it produces Workflow software · simulated data

Inquiry desk

A landscaping company's estimate requests, checked, matched against earlier requests, saved once to the CRM and announced to the team. A failed alert waits for a deliberate retry, so no lead goes missing and nobody is messaged twice. Runs in your browser; nothing is sent.

Try the demo
Grooming salon booking demo: the headline Hands in the tub, bookings still moving, the four steps from request to groomer queue and the phone request form Workflow software · simulated data

Grooming salon booking

A grooming salon's booking loop: a short request form that fits on a phone, an instant reply, a text back for every missed call and one queue the groomers clear between dogs. Placeholder brand and made-up data; nothing is sent.

Try the demo
Pet resort reservations demo: a free-text boarding message beside the complete request that replaces it, and the four steps from booking to rebooking Workflow software · simulated data

Pet resort reservations

A pet resort's reservations: requests arrive complete with dates, pets and vaccine records, guests get an instant confirmation, a rebooking reminder follows every checkout and the front desk starts from one screen. Placeholder brand and made-up data; nothing is sent.

Try the demo
Auto shop front desk demo: the headline Every call reaches the right shop, above a before and after of a two-location contact page Workflow software · simulated data

Auto shop front desk

One front desk for a two-location auto shop: each call button dials the right shop, appointment requests go to that shop, missed callers get a text back and both shops share one queue. Placeholder brand and made-up data; nothing is sent.

Try the demo
Pairwise presentation PDF: an admin review screen explaining a suggested pairing Product design · PDF

Pairwise

An admin review flow for a mentoring network: explain each suggested pairing, keep exceptions visible and leave the decision to people. Static screens with sample data.

Open the PDF

Products & R&D

Developer tools · silent demo videos

Tools we build for our own engineering work. Each has a short overview clip and a walkthrough.

Product demo · video

Strata

A workbench for AI-assisted engineering. Every change moves down one line, from intake to verification, and only checked work is promoted.

Strata in 22 seconds: build the rigor around the model, and only checked work comes out.
Walkthrough: a recorded run moves down Strata's line, and the verifier decides which changes are promoted.
Code
Product demo · video

Seedling

A self-improvement loop for coding agents. Each attempt runs sealed and is scored before anything is applied.

One recorded Seedling cycle: a sealed rewrite is scored, then applied.
Walkthrough: replay a cycle from its logs (quarantine, scoring, apply), then re-run the scorer yourself.
Code
Product demo · video

Lightning

Branching for local models. A saved cache lets one conversation fan out into several continuations without recomputing what they share.

Lightning: one query fans out to four branches from a restored cache.
Walkthrough: the measured cache run, then a branch continued from an earlier checkpoint in the inspector.
Code
Product demo · video

Conduit

A local front door for tools that want to run on your machine. Conduit shows what a tool is asking to do and asks you before something new runs.

Conduit: a clearer way to install and run a tool than piping a script into your shell.
Walkthrough: run the consent demo, then watch Conduit Control ask about a request it has not seen before.
Code

Open source

Six public repositories
  • Strata Python · Apache-2.0

    The engineering workbench in the Strata video.

  • Seedling Python · Apache-2.0

    The sealed self-improvement loop in the Seedling video.

  • Lightning TypeScript · Apache-2.0

    Cache-restored branching for local models, as in the Lightning video.

  • Conduit TypeScript · Apache-2.0

    The local consent front door in the Conduit video.

  • Alight Swift · MIT

    A native macOS menu bar gauge.

  • Cosmo Python · Apache-2.0

    Research source: a small harness for testing whether explicit process helps local models do better work.

Tell us what you need