homey-app-dev

Homey App Development (SDK v3)

Authoritative documentation — fetch it, don't guess

Homey publishes the full Apps SDK documentation in machine-readable form:

• Index of every page: https://apps.developer.homey.app/llms.txt
• Any docs page is available as markdown by appending .md to its URL, e.g. https://apps.developer.homey.app/the-basics/devices/capabilities.md
• SDK API reference (Device, Driver, Homey, FlowCard classes): https://apps-sdk-v3.developer.homey.app

When unsure about a manifest field, capability, or SDK API, fetch the relevant page instead of relying on memory. Key pages: the-basics/app/manifest.md, the-basics/devices/capabilities.md, the-basics/flow.md, the-basics/devices/energy.md, advanced/homey-compose.md, app-store/guidelines.md.

Runtime and compatibility model

• Apps declare "sdk": 3 and a "compatibility" semver range of supported Homey firmware versions (not hardware models). Minimum allowed is ">=5.0.0".
• All Homey hardware still receiving firmware updates — including Homey Pro (Early 2016/2018/2019) — runs the latest firmware. Supporting older hardware means supporting the firmware range, and thereby its Node.js version:

Platform	Firmware	Node.js
Homey Pro (2016–2019)	< 7.4.0	12
Homey Pro (2016–2019)	7.4.0 – 12.8.x	16
All platforms	>= 12.9.0	22

• Consequence: pick the TypeScript target and @types/node major to match the lowest Node version implied by the app's compatibility. This app declares ">=12.2.0", so the floor is Node 16 (older 2016–2019 hubs on firmware 12.2–12.8): keep @types/node at ^16 and the compile target at ES2021, even though tooling runs on newer Node.
• Apps are plain Node.js (CommonJS by default; ESM possible), entry point app.js/app.ts, running sandboxed on the hub itself.

Project structure (Homey Compose)

app.json is generated — never edit it by hand. Sources live in:

• .homeycompose/app.json — id, version, compatibility, sdk, brandColor, category, name/description (i18n objects), permissions, author, contributors.
• .homeycompose/capabilities/<name>.json — custom (non-system) capabilities: type (boolean/number/string/enum), title, getable/setable, uiComponent, enum values with translated titles.
• drivers/<driver>/driver.compose.json — driver class, capabilities list, energy object, pair views, images.
• drivers/<driver>/driver.flow.compose.json — flow cards scoped to the driver: triggers, conditions, actions, each with translated title/hint, optional args and tokens.
• drivers/<driver>/driver.settings.compose.json — device settings shown in the mobile app.
• .homeycompose/flow/ — app-level (non-device) flow cards, if any.
• locales/<lang>.json — app-wide translations referenced as { "en": ..., "no": ... } objects.

Regenerate app.json with npx homey app build (or any run/validate command, which composes first). After changing any compose file, rebuild and commit the regenerated app.json alongside the sources.

Translations: this app maintains en, no, nl, sv, de. Every new user-visible string (capability titles, enum values, flow card titles/hints, tokens) needs all five.

Devices, capabilities, flows — core patterns

• Driver.onInit registers flow cards: this.homey.flow.getDeviceTriggerCard(id), getConditionCard(id).registerRunListener(...), getActionCard(id).registerRunListener(...). A trigger card declared in compose but never fetched+triggered from code silently does nothing.
• Device.onInit registers capability listeners (registerCapabilityListener('onoff', ...)) for setable capabilities and starts polling/subscriptions.
• Update state with setCapabilityValue(cap, value) (returns a promise — attach .catch(this.error)).
• Adding/removing capabilities on existing devices requires addCapability/removeCapability migration in onInit — capabilities in the manifest only apply to newly paired devices.
• Enum capability values are string IDs; adding new enum values to an existing capability is backward compatible, removing/renaming breaks users' flows.
• energy objects (per driver or device class evcharger, cumulative, etc.) power the Homey Energy tab — see the-basics/devices/energy.md.
• Device class changes (e.g. to evcharger) need a setClass migration in onInit.
• Multiple picker capabilities (undocumented, verified empirically July 2026 on the iOS app): the device view shows ONE picker widget with a dropdown menu to switch between picker capabilities. The menu lists them in capability order, but the DEFAULT selection is the LAST picker capability in the device's capability order — so put the picker you want as default last among the pickers. Not sticky: the app recomputes the default every time the device view opens. Order changes on existing devices require a capability rebuild (remove+re-add all in the new order) in onInit, since set-based change detection won't fire.

CLI (npx homey ...)

• homey app validate — manifest validation; --level=publish for the App Store bar (this repo's target).
• homey app build — compose + TypeScript compile. The CLI requires tsconfig.json outDir to be ./.homeybuild.
• homey app run — run on a hub in dev mode with live console; homey app install — install without console.
• homey app publish — push to the App Store (asks to bump version; pre-release versions not allowed).
• homey app version patch|minor|major — bump version in .homeycompose/app.json + app.json.
• homey app driver create, homey app flow create, homey app driver flow create — scaffolding.
• First use: homey login.

Publishing checklist

1. npm run build (tsc) and npm run lint pass.
2. npx homey app validate --level=publish passes.
3. Version bumped (compose + app.json in sync; package.json version kept matching by convention).
4. Changelog: .homeychangelog.json if present; App Store “What’s new” text on publish.
5. Review App Store guidelines (app-store/guidelines.md) for naming, images, and description rules.

This repository's specifics

• myenergi cloud API client lives in the myenergi-api npm package (same author); device data models (Zappi, Eddi, Harvi) come from there. Zappi status combines pilot state (pst) with device state (sta) — see drivers/zappi/device.ts getChargerStatusText.
• Data flows: app.ts polls the myenergi cloud per hub credential → drivers relay via registered callbacks → devices update capabilities in dataUpdated.
• Energy values from the myenergi API history endpoints are in joules (watt-seconds); instantaneous values are watts.