Mold Studio Companion (iPhone and iPad)

Mold Studio Companion is the native SwiftUI app for mold on iPhone and iPad, and the little sibling of Mold Studio for Mac. It is remote-only: the phone never runs a model. It drives the mold serve machines you own, and everything it makes stays in their libraries.

It appears as Mold Studio on the Home Screen, needs iOS / iPadOS 26, and installs beside the older iPhone app rather than replacing it. Builds go out through TestFlight while it is new.

Add a machine

Open Machines ▸ Add a Machine… and pick one of three ways in:

• Scan a Pairing Code. On your Mac, choose Pair a Phone… from a machine's card menu or the Machine menu in Mold Studio (or Settings ▸ Mobile pairing in the desktop or web app), and point the camera at the code. For a machine with an API key the code is single-use, expires after two minutes, and carries no key; the key the machine issues goes straight into this device's Keychain. For a machine without a key, the code simply carries its address. The code is a link, so the iPhone's own Camera opens Mold Studio too: it names the machine and pairs only when you tap Pair. You can paste a pairing link instead. On a phone without the app, the link opens a page that says what to install; the code itself never reaches the web.
• Nearby. Machines advertising _mold._tcp on your network are listed. Allow Local Network access when iOS asks.
• Enter an Address. An IP address, host name, Tailscale MagicDNS name or HTTPS URL. The address is checked as you type and the answer is shown as a sentence. Add the machine's API key if it has one.

A machine that is offline keeps its place, dimmed, with the reason.

Generate

On iPhone, Generate is one scrolling form. Choose Still picture / Short clip / 3-D object and a machine (or leave it on Auto) above the prompt. Tap Model to search installed models and recipes; Get More Models… opens model management directly. The controls come from the model itself: a model that reads a starting picture shows Start from; one that takes references shows numbered wells (image 1, image 2) matching how the prompt names them; clips add a length; 3-D objects say when the prompt is ignored. More options holds the sampler, seed, adapters, identity photos, ControlNet and the mask editor, and only what the model can use. Shape, Steps, Batch and clip Length have separate rows that remain readable at large text sizes. At larger text sizes Kind and Machine stack. On iPhone Generate stays above the tabs as a full-width button, and the parameter chips become one Options button. Clip and 3-D drafts keep their kind when you reopen the app. A model search with no matches offers Clear Search. Model search also keeps a Close Model Search action above the keyboard at large text sizes.

Generate never turns into Stop. Pressing it again queues another render; Stop is its own small button beside the progress sentence, e.g. "Adding detail — about 12s left" over denoise 18/28.

The full-screen viewer hides the main tabs so Share, Favourite, Info and Delete remain reachable; use Back to return to the Library. Info has a Done button. Clips play when their page appears and pause when you page away. Returning to the Library keeps your place in the grid. Shared media keeps its original filename and file type.

Library, Queue and Models

• Library keeps working offline: it shows each machine's saved prints when the machine isn't answering, and the prints you have opened. Pinch to change the tile size (five sizes, from seven columns to one). Settings ▸ Library sets how much space it may use and can save every thumbnail ahead of time. It reports image storage against its limit and lists saved listing storage separately; Clear Library Cache explains that prints on offline machines will disappear from this phone until they reconnect.
• Library shows every machine's prints as one grid, a print found on two machines once. Favourites, tags, collections and Recently Deleted work the way they do on the Mac, across every machine that holds a copy. On iPhone, tap the navigation title to change shelves; it stays readable as you scroll. Status notices reserve space above the grid so dates and prints stay visible. Media Type offers All Media, Photos, Videos and 3D within any shelf. Tap Select, then tap tiles or sweep sideways across them. Starting on a selected tile deselects the range; reverse to shorten it, or hold near an edge to scroll. Vertical swipes still scroll in Select mode. Search understands is:video, is:mesh, tag: and on:.
• Queue lists what each machine is rendering and waiting on. A held job says why in words, with Pull and Retry when a model is missing, Retry when the machine says it would help, and Move to… another machine.
• Models uses the Show models menu to switch Installed and Discover. An unreachable machine's unread inventory is shown as unavailable, not empty.
• Models (Machines ▸ Models on iPhone, the sidebar on iPad) lists what a machine has installed and lets you discover, download, load and remove models. A gated model shows its licence first.

On the Lock Screen

While a render runs, a Live Activity shows its preview, the progress sentence, the time left and a Stop button, on the Lock Screen and in the Dynamic Island. The translucent card keeps the prompt compact, gives progress its own row, and places the machine and waiting count together in the footer. Large text uses a simpler layout to keep the status and Stop control readable. mold servers cannot push to a phone, so once the app is in the background the activity is refreshed only when iOS lets Mold Studio run; it says "Open Mold Studio to refresh" when it may be out of date.

When a render finishes, fails or is held while the app is away, a notification says so; tap it to open the print. Each kind can be switched off in Settings.

Widgets

• Recent Prints (small, medium, large): your newest prints, from every machine or one, all of them or favourites only.
• Queue (Lock Screen): "2 rendering · 1 held", a progress ring, or one inline line.

Widgets show what the app last saw; they never contact a machine themselves.

Share a photo to Mold Studio

In Photos (or any app), Share ▸ Mold Studio and choose Start From, Reference Image or Add to Library. The share sheet only saves the photo for the app, downscaled to 2048 px; open Mold Studio and the From Share card in Generate finishes the job.

Text size and accessibility

Every screen is audited from the smallest text size to the largest accessibility size, in light and dark, on iPhone and iPad. Rows that put a label beside a value stack at accessibility sizes instead of truncating, and empty screens keep their one action above the tab bar.

Privacy

The app talks only to the machines you add. Keys live in this device's Keychain. See the privacy policy for the camera, local network, Photos and notification permissions and what each is used for.

Native development

nix develop -c companion-dev watches Swift sources and rebuilds/relaunches the native app in Simulator. Use companion-run to launch once and companion-build to build only. Pass SIM=<UDID> and BUILD=<directory> through any helper. These commands are separate from Tauri's ios-dev.

The prompt panel scrolls at large text sizes and stays above the keyboard. Video playback uses the media audio session, so clips with audio can be heard even when the phone's silent switch is on. Clips without an audio track remain silent.

When machines are offline, Generate and Queue explain that their data is unavailable instead of claiming no models or jobs exist. A saved draft keeps its model while that machine reconnects; choosing a different kind or model explicitly replaces the pending selection.

Render completion notifications use the native iOS banner and Mold Studio app icon, with a short readiness message instead of the full prompt or an image attachment. Tap to open the finished print, including after the app has been closed; cancelled Library refreshes keep existing prints without an error banner.

Generate Options shows aspect-ratio icons in their actual proportions. With a source picture attached, Fit offers centered Crop to fill by default, Fit with borders, Stretch to fill, and Fit + repaint borders when masks are supported. Crop positioning offers horizontal and vertical alignment. Source pixels and painted masks are fitted together before submission. Seed defaults to Random; choose Fixed to reuse a seed. Reset returns fitting to centered Crop to fill and the seed to Random. Explicit saved settings and draft choices remain restorable.

Hold a Library tile to preview it and open its actions. Source-image selection also remains usable after a long press. The notification icon uses the same Mold logo in light and dark appearances; the system controls the notification card background.

When a Library print is saved on several machines, the source-image picker uses a currently reachable copy, including when the first listed machine is offline.

Live Activity cards use ActivityKit’s default material so the background and text follow the Lock Screen appearance together, including the stale “Open Mold Studio to refresh” state.

Find curated models and reuse their inputs

In Models ▸ Discover, Mold Models lists the curated checkpoints your machine can fetch, including uninstalled variants. Search their readable name, family, or Hugging Face repository. Hugging Face and Civitai marks identify the source. Get installs one exact variant using the machine's configured credentials; licence acceptance still applies. The same readable model names appear across Mold's apps and CLI, with the stable model ID available separately.

Use These Settings restores a print's retained source image and repaint mask into the composer before fitting. Other retained conditioning files are named beside the composer and remain available across prompt edits and repeated renders. Remove retained sources clears those attachments; replacing an image keeps your choice. Unavailable retained files are explained inline.

The Queue shows the prompt and actual Source image separately from the live Rendering preview, including when the source belongs to a durable job that survived a machine restart. On iPad, jobs stay within a readable centered column.

Server model memory

In Machines → Models → Installed, use Unload beside a resident model or Unload All Models for the selected server. Downloads remain installed. Offline and pending-operation controls are disabled, and server refusals remain visible.