Even Hub Case Studies — architectural patterns from 7 production G2 apps

Case studies and architectural notes from shipping 7 production apps on the Even Realities Even Hub platform for the G2 smart glasses.

This repo is not a general SDK reference or UI library — those already exist (see below). What's here is the stuff that tends to live outside the glasses themselves: how to pair the G2 with a companion mobile app, how to offload work to a backend, how to instrument errors from a WebView, how to produce images the SDK will actually render, and how to test pure logic without a Jest setup. Plus short case studies of the 7 apps where these patterns are exercised in production.

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Canonical references

Before anything here, look at these. They are the references this repo complements rather than duplicates.

Repo	What it is
nickustinov/even-g2-notes	Community documentation bible — the go-to SDK reference, event catalog, and protocol notes.
fabioglimb/even-toolkit	UI library and design system. Pioneered the working pixel-art recipe with upng-js.
even-realities/evenhub-templates	Official starter templates from Even Realities.
even-realities/everything-evenhub	Official Claude Code plugin for G2 development.

If you're new to G2 development, start with those. Come back here when you need a companion app, a backend, telemetry, or want to see how a full app is wired end-to-end.

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What's here

Patterns beyond the glass, all learned while shipping the apps listed below:

• docs/mobile-companion.md — Expo app + expo-notifications forwarding to the G2 via Even's native notification bridge. How to build reminder-style apps without the G2 app staying open.
• docs/distributed-backend.md — Express + SSE pattern for offloading work. Used by Speech Coach for real Whisper STT.
• docs/telemetry.md — Cloudflare Worker + KV for remote error reporting from WebView apps.
• docs/testing.md — state/logic test pattern using tsx directly, no Jest setup.
• docs/pixel-art.md — sprite → 16-level greyscale → indexed PNG with upng-js, and how it hooks into updateImageRawData.
• docs/sdk-quirks.md — catalog of quirks we hit in production (sysEvent vs textEvent, eventType: 0 normalization, image size limits, etc.).
• docs/event-handling.md — drop-in parseEvent + handler skeleton.
• docs/lifecycle.md — foreground/background, device info, battery awareness, graceful shutdown.
• docs/dev-workflow.md — hot reload with evenhub qr, simulator vs hardware gotchas, debug patterns.
• docs/getting-started.md — minimum viable app scaffold.

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Case studies — 7 production apps

Each repo is open source and its own case study.

App	What it explores
hunter-g2	Place discovery with Overpass + Serper fetch, offline cache, OSRM walking routes, pixel-art category icons.
eyefit-g2	Eye exercise guidance with IMU head tracking, pixel-art character, lifecycle-aware session persistence.
speechcoach-g2	Live speech pace coaching — audio capture → backend Whisper STT over SSE, VU meter, pixel-art mascot.
glance-g2	Personal dashboard aggregator — multi-source data on a minimal display.
whatsapp-g2	WhatsApp messages from a Win11 bridge + voice reply via Whisper STT.
storywalk-g2	Contextual tourism / running companion — GPS-tracked POI storytelling.
breakmate-g2	Health reminders — animated pixel-art character, multi-frame walking animation, paired with an Expo companion.

Companion repos referenced from the patterns above:

• breakmate-mobile and eyefit-mobile — Expo companions with expo-notifications.
• speechcoach-backend — Node + Express + SSE backend for STT.
• g2-telemetry-worker — Cloudflare Worker error endpoint.

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Submission compliance

All 7 apps received the same submission-compliance fix to call shutDownPageContainer(1) on the double-tap root (replacing the earlier bridge.exit / shutDownPageContainer(0) paths that the review flagged). The fix PRs, one per repo:

• hunter-g2#1
• eyefit-g2#1
• speechcoach-g2#1
• glance-g2#1
• whatsapp-g2#1
• storywalk-g2#1
• breakmate-g2#1

If you hit the same submission rejection, those PRs show the minimal diff.

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Contributing

PRs welcome — especially corrections, counter-examples, or new patterns we haven't documented. See CONTRIBUTING.md.

For SDK reference material, please contribute to nickustinov/even-g2-notes instead. For UI components, see fabioglimb/even-toolkit. This repo stays focused on architectural patterns and case studies.

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License

MIT. See LICENSE. Use freely, share freely.

Disclaimer

Not affiliated with Even Realities. Community project documenting what actually worked in production as of SDK v0.0.9.