Bridge is the desktop app that turns First Crack from a web-based logger into a real-time live-roasting platform. Install it on your Mac or Windows machine, plug in (or pair Bluetooth, or join the WiFi of) a supported roaster, sign in, and the web app's Live Roast page lights up: BT, ET, rate of rise, heater power, fan speed, drum speed — all streaming at one-second resolution, all backed up to the cloud as you roast.
This is the article for roasters researching the desktop side of First Crack. It covers what Bridge is, what it supports today, how a Live Roast actually feels next to a Guided Roast in the browser, how Bridge compares to Artisan running against the same hardware, and how to get on the beta list.
If you're newer to First Crack and want to know what the platform is in general, About First Crack is a better entry point. If you don't have hardware yet and want to roast in the browser today, read about Guided Roast — it's the same chart and the same analytics with typed probe readings instead of sensor streams.
What Bridge Is
Bridge is a native, signed, notarized desktop app. macOS build is universal (Apple Silicon + Intel). Windows build is x64. Both run a small local WebSocket server (ws://localhost:8765) that the First Crack web app's /live-roast route connects to as soon as you open it.
It does three things:
- —Talks to your roaster. Over USB-serial, Bluetooth RFCOMM, or WiFi, depending on the model. Translates protocol messages into a clean wire format the webapp understands.
- —Buffers an in-flight roast. If you reload the tab or your laptop goes to sleep mid-roast, Bridge keeps the live session alive on its end. When the tab comes back, it replays the session and the chart picks up where you left off.
- —Pushes data to the cloud. Every sample lands in your account in real time, so a roast captured on Bridge is immediately visible on your phone, on the web app on another laptop, or to anyone you've shared the live link with.
Bridge is not a logger that runs without First Crack. It's the connector — your roaster on one side, the cloud-backed First Crack platform on the other. The web app is where the chart, analytics, recipe playback, inventory, cupping, and sharing live.
Supported Roasters Today
Bridge supports the Kaleido M-series and Croaster on day one. More are landing as the beta-signup voting roadmap fills out.
Kaleido M-series
Both the M1 (200 g, home scale) and M10 (1.2 kg, small-batch production) are confirmed working — and the rest of the M-series shares enough of the protocol that we're framing support model-wise rather than per-machine.
Two connection paths:
- —USB-serial — plug the included cable, Bridge picks it up automatically. Most stable, fastest reaction time.
- —Bluetooth RFCOMM — pair once, Bridge remembers the device. Useful when the Mac/PC isn't physically adjacent to the roaster.
Bridge reads BT, ET, rate of rise, heater power (HP), fan control (FC), and drum/rotor control (RC) from the Kaleido firmware. It also drives the roaster: HP, FC, RC, and Target Setpoint (TS) can be commanded from the live UI or from a recipe.
Croaster
Bridge connects to Croaster over your local WiFi network. The Croaster protocol is monitor-only — Bridge reads BT, ET, and event marks but does not have a control surface (the Croaster firmware doesn't expose one).
You still get the full live chart and analytics, you just operate the roaster's controls by hand the same way you do today.
What's next
The beta signup form lets you select your hardware model — if it's already supported, you get a magic-link invite. If it isn't, the request is logged as a roadmap vote. We bring up the roasters with the most signups first. Today the top of that list (besides Kaleido and Croaster) is largely shop-built and small-batch drum roasters; the more votes a model accumulates, the sooner it ships.
What the Live Roast Page Looks Like
Open /live-roast after installing Bridge and signing in, and the page is split into a few information regions:
Big readouts at the top
- —Bean Temperature (BT) — the primary value the chart plots.
- —Environmental Temperature (ET) — drum or air temp depending on probe placement.
- —Rate of Rise (RoR) — derived from BT, in °F/min.
- —Heater Power, Fan Control, Rotor Control — for Kaleido, the current commanded values.
The chart
- —BT line in the brand's bean-temp orange.
- —ET line in env-temp blue.
- —RoR line in RoR green on a secondary axis.
- —Phase color bands (drying / Maillard / development) once enough events have fired.
- —Event markers — CHARGE, TP, Dry End, First Crack Start/End, Second Crack Start/End, Drop.
- —Optional reference-roast overlay: pick a previous roast and its curve is rendered semi-transparently underneath so you can coach the current roast against a target shape.
The event keyboard
- —Eight event buttons. Keyboard cycles through them — press Enter to fire the highlighted event at the current BT and elapsed time.
- —Same shape as Guided Roast's event grid because they're the same UI.
Controls (Kaleido)
- —Heater, fan, drum steppers — adjust from the web UI and Bridge ships the command to the roaster. Setpoint changes echo back through the same channel so the popup stepper and the web UI never disagree.
- —"Awake" pill: holds a wake lock on your laptop while the roaster is connected so the screen doesn't sleep mid-roast.
Onboarding cards
If something isn't right, the page shows a contextual card explaining what's missing — Bridge not running, no paired roaster, bridge running but the roaster's offline. Each card has one tap to fix.
How It Differs From Artisan
Artisan is the standard for connected coffee roasting on a single machine. If you've been running Artisan against a probe-equipped Kaleido for years, you have a working setup. The honest comparison:
- —Multiple platforms. Artisan supports macOS, Windows, and Linux. Bridge supports macOS 26+ and Windows 10 build 19041+ / Windows 11. If you're on Linux, Artisan still wins for the live session.
- —Hardware breadth. Artisan supports a much larger catalog of probe interfaces, configured by years of community contributions. Bridge supports the specific hardware First Crack has tested and shipped a driver for. Bridge will close that gap over time but is starting with depth-on-a-few rather than breadth-across-everything.
- —What happens after the roast. This is the biggest difference. Artisan ends when the roast ends — your .alog file is on your machine. Bridge feeds the full First Crack platform: cloud sync, bean inventory deduction, cupping workflow, recipe management, public sharing, side-by-side comparisons, community browse, analytics dashboards across your whole library. None of that exists in Artisan.
- —Sync between session and library. Bridge syncs every sample to the cloud in real time. The minute the roast ends, the profile is everywhere you've signed in. Artisan is single-machine by design.
- —Cost. Artisan is free and open source. First Crack's web platform is free; Bridge is currently free during private beta. Long-term Bridge pricing has not been announced.
Many roasters in the beta run both: Artisan for the live session on hardware they've tuned for years, First Crack for everything after — analytics, cupping, sharing — with the .alog import bringing the history along. That's a totally legitimate stack. Bridge becomes the upgrade path when you're ready to consolidate.
For the side-by-side rundown with all the rows, see First Crack vs. Artisan.
How to Get Bridge
Bridge is in private beta. Approvals happen by hand at firstcrack.app/beta — small numbers, high care. The flow:
- —Sign up at
/beta. Pick your roaster model and connection method (USB / Bluetooth / WiFi / Other). - —We read every signup. If your roaster is supported, you get a magic-link invite + a Bridge download link, usually within a few days.
- —If your roaster isn't supported yet, your request is recorded as a roadmap vote. You can still use Guided Roast in the browser today.
- —Once approved, install Bridge, sign in, open
/live-roast, and pair your roaster. The pairing flow guides you through device discovery and adoption.
System requirements:
- —macOS 26 (Tahoe) or later, Apple Silicon or Intel.
- —Windows 10 build 19041 (May 2020 update) or later, or Windows 11. x64 only.
- —Roaster connected by USB, paired over Bluetooth, or sharing a local WiFi network — depending on the model.
The Bridge build is signed and notarized on both platforms — Windows users may see a SmartScreen warning the first time you launch (we're working on that); on macOS, Gatekeeper should accept it without an override.
What's Coming
A few near-term roadmap items worth knowing about:
- —More roasters. The beta-signup vote tallies drive the order. Every signup helps move your model up the queue.
- —Heater/fan/drum control from recipes. Already wired for Kaleido — the UI for editing the recipe step DSL is incrementally getting better.
- —Reference overlay across the catalogue. Pick any previous roast — yours or a public one — as a target curve while you live-roast.
- —Operator-set defaults. Charge HP/FC/RC, target charge temp, target drop temp — all configurable per-user and per-recipe.
- —More analytics. Bean-level performance trends, cupping integration, RoR shape fingerprinting.
Bridge is the forward direction at First Crack. The standalone macOS app you may have seen earlier is being absorbed into this same architecture; Bridge is where new live-roasting capability ships first.
Ready?
If you're roasting on a Kaleido M-series or Croaster — or you want your roaster on the roadmap — request Bridge beta access. If you're not sure whether your setup qualifies, the beta form lets you describe your hardware and we'll read it.
If you want to start collecting roast data tonight without waiting on hardware, Guided Roast is ready in any browser. The data lands in the same library, so when Bridge does come online for you, your history is already there.