Dev tests GPT-6.1 Sol ultrafast: 8x faster SwiftUI editing

iOS developer Dimillian posted a series of threads on his experience with OpenAI's GPT-6.1 Sol ultrafast mode: for quick edits on native SwiftUI apps, it is up to 8x faster than standard mode, and paired with the right agentic workflow it can unlock new ways of developing.

Confirmed

In quick SwiftUI editing scenarios, ultrafast runs up to 8x the speed of standard mode (per Dimillian's testing).
Combined with merowing's Inject and InjectionIII libraries, iOS apps can hot reload without recompiling—you can speak to the app in natural language and see UI changes instantly, building features and components "at the speed of thought."
Dimillian says that after using it for a while, his workflow changed noticeably: it's fast enough to stay in flow with the model and iterate immediately, letting him focus on a single task without constant context switching.
Pricing: $12 per million input tokens and $60 per million output tokens, slightly above GPT-6 Astra; available in the EU too; accessible via the $500 Pro subscription tier.

Why it matters

Hot reload plus a high-speed model pushes iOS development toward "conversational, instant UI editing." If the experience really sustains flow as Dimillian describes, agentic coding workflows could become a routine option for native iOS development.
At $12 per million input tokens—slightly above GPT-6 Astra—this extreme speed carries a clear cost premium, so developers need to weigh speed against expense before adopting it.

2026-10-09 ~ 2026-10-09 · 5 related posts

Primary sources

GPT-6.1 Sol ultrafast demo: 8x faster SwiftUI edits with hot reload — Dimillian · 2026-10-09 02:30 (UTC+08:00)
GPT-6.1 Sol Ultrafast priced at $12/$60 per million tokens, available on $500 Pro plan — Dimillian · 2026-10-09 02:30 (UTC+08:00)
Hot reload plus GPT-6.1 ultrafast: edit SwiftUI apps by talking — Dimillian · 2026-10-09 02:30 (UTC+08:00)

[source] GPT-6.1 Sol ultrafast demo: 8x faster SwiftUI edits with hot reload — Dimillian · 2026-10-09
[source] Hot reload plus GPT-6.1 ultrafast: edit SwiftUI apps by talking — Dimillian · 2026-10-09
SwiftUI hot reload without recompiling: tweak UI at thought speed — Dimillian · 2026-10-09
Developer says ultrafast changed his flow: focus and iterate instantly — Dimillian · 2026-10-09
[source] GPT-6.1 Sol Ultrafast priced at $12/$60 per million tokens, available on $500 Pro plan — Dimillian · 2026-10-09