Bridgeless Apple Home Integration for Mitsubishi, Daikin, Fujitsu, and Other Japanese Split-AC Brands
Mitsubishi Electric, Daikin, Fujitsu, and Hitachi own the heat-pump market in much of the world, ship their own MELCloud/D-Mobile/etc cloud apps, and each refuses to sign on to Apple Home, leaving owners to either pay $199 per Sensibo IR-bridge per unit or rely on dealer-installed Kumo modules with limited shortcut support. The opportunity is a software-only iOS app that sits on top of MELCloud's existing API plus equivalents and exposes them as native HomeKit accessories without dedicated hardware.
Mitsubishi will not respond to your support emails. Don't ask. Build against MELCloud and the equivalent Daikin/Fujitsu cloud APIs the way the Home Assistant community already does. Charge $30 one-time per household, or $20/year for cloud relay if Apple kicks you off the local-only path. Beware: any one of these vendors could ship native HomeKit tomorrow and instantly kill the wedge for that brand. Multi-vendor coverage is the moat.
landscape (4 existing solutions)
The native cloud APIs are all already publicly accessible (the open-source Home Assistant integrations prove this). The gap is a polished consumer iOS app that does the bridging without making the user learn Home Assistant or buy hardware they don't need.