Inside LLM
See inside a language model
Free · In-App Purchases · Designed for iPad. Not verified for macOS.
Type a sentence and watch a real 82-million-parameter GPT-2 predict your next word, layer by layer, entirely on your device.
Ever wondered what your keyboard is doing when it suggests the next word? Inside LLM runs a real language model on your iPhone or iPad and draws every step of its thinking.
This is not a chatbot and not an online service. The app contains its own transformer inference engine, written from scratch in Swift on Apple's Accelerate framework, and computes the full network on your device after every keystroke so that every intermediate number can be shown.
Type anything and see:
- Suggestions: the three most probable next words, exactly as a predictive keyboard would show them, with their real probabilities.
- Signal through the network: six layers lighting up as the forward pass runs.
- Attention: a heatmap of which earlier words each token is reading from, for any of the 72 attention heads, or averaged.
- Neurons: all 3,072 MLP neurons in each layer, firing for your last word.
- Logit lens: what the model would guess if it stopped after layer 0, 1, 2, and how that guess sharpens or changes as it goes deeper.
- Weights: every one of the model's 76 weight tensors, rendered as a zoomable heatmap of the actual numbers learned in training.
- Steps: a six-step walkthrough of one forward pass (tokenize, embed, attend, MLP, stack, softmax) using your own words as the example.
Everything runs locally. No account, no analytics, no ads. Nothing you type leaves the device. An optional tip jar in About lets you support development; tips unlock nothing and every feature is free.
The model is DistilGPT2 (Hugging Face, Apache 2.0), an 82-million-parameter distilled GPT-2 trained on 2019 web text. Its suggestions are shown for learning purposes and can be wrong or dated. The engine's output is checked against an independent reference implementation in the app's test suite, and the method is described in an open technical report.
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Orch Neural Network is now Inside LLM. New: an optional tip jar in About (tips unlock nothing; everything stays free). Cleaner labels throughout.
The developer, Wonmo Seong, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Wonmo Seong
- Size
- 168.1 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Large tip USD 11.99
- Medium tip USD 5.99
- Small tip USD 1.99
- Copyright
- © 2026 Wonmo (John) Seong