Mobile app

Native Expo (SDK 57, React Native 0.86) client in app/. It uses the same protocol, the same contracts and the same business logic as the web app:

config/networks.json + packages/core (ABIs, policy check, accounting, verification, key derivation)
        |                                   |
     web/ (Next.js)                       app/ (Expo)

Metro resolves @imprest/core straight from the monorepo (app/metro.config.js); nothing is copied. One passkey derives the same Imprest account on both clients (deriveEvmKey in core; app/test/shared.test.ts).

Screens

Screen	Shows	Actions
Home	account, AUSD and MON balances, desk equity, stake, restricted credit, unrealized PnL, HWM, risk floor, daily loss remaining	create/sign in with passkey, testnet faucet, approve and open desk
Trade	BTC/ETH mark (Perpl API), long/short, size, leverage, "your capital + restricted credit = maximum position", shared policy check	sign and send the order to the desk; status requested -> submitted -> verifying -> verified
Positions	size, entry, mark (stale flag), exposure, margin, unrealized PnL	none
Risk	leverage, drawdown, daily loss, exposure and fee utilization; contract limits	none
Claims	realized profit above HWM, fees netted, trader/pool/protocol shares, eligibility reason	claim when eligible
History	desk events from a bounded RPC scan	none

Vocabulary matches the web app: "restricted credit", "risk floor", "high-water mark".

See it on your phone (5 minutes, free)

Install Expo Go from the App Store or Google Play. Use the version that supports SDK 57.
Put the phone on the same Wi-Fi as this computer.
In the repository root, run:

npm run mobile

A QR code appears in the terminal. It only appears in a real terminal window, not when the output is piped to a file.

Scan it. On Android, use the scanner inside Expo Go. On iPhone, use the Camera app.
If the phone cannot connect (guest Wi-Fi, a corporate network, or a firewall), stop and

run cd app && npx expo start --tunnel instead.

What works in Expo Go and what does not

Works	Does not work in Expo Go
Every screen and navigation	Passkey sign-in. Passkeys need a native module and a domain linked to the app. Expo Go has neither, so the app shows `RP_ID_NOT_CONFIGURED`. It never pretends to sign you in.
Live BTC/ETH marks from Perpl testnet	Sending trades, opening a desk, claiming (all need the signed-in account)
	Risk limits, positions, claims and history (all read from your own desk, so they need the signed-in account)

In short: Expo Go shows the real app reading real testnet data. Trading from the phone needs the development build described below.

Verified so far

Check	Result
`npm run typecheck`	clean
`npm test` (shared logic)	3/3 pass
`npm run bundle:check` (Android JS bundle via `expo export`)	exports
`npm run mobile` starts Metro; manifest served (SDK 57, "Imprest"); Android dev bundle served (16 MB, HTTP 200)	LOCAL, 2026-10-07
Opened on a physical phone (owner's iPhone, Expo Go, 2026-10-08)	Home rendered with the network badge, the six-tab bar and the honest `RP_ID_NOT_CONFIGURED` notice. Owner screenshot.
Trade, Positions, Risk, Claims and History tabs on the phone	PENDING owner check: tap each tab; Trade should show live BTC/ETH prices, the others ask to sign in

Passkeys on a phone: what is needed and why

Why: iOS and Android only release a passkey to an app the domain owner has vouched for. The website proves this by publishing two small files, and the app declares the same domain. Without that link the operating system refuses, which is the anti-phishing design.

What, where, how much:

Item	Where	Cost
A domain you control (e.g. `imprest.xyz`)	any registrar	about $10–15 per year
Host the web app on it over HTTPS	Vercel, Netlify or Cloudflare Pages free tier	$0
`/.well-known/apple-app-site-association` with `{"webcredentials":{"apps":["<TEAMID>.xyz.imprest.app"]}}`	`web/public/.well-known/` (I generate it once you give me the Team ID)	$0
`/.well-known/assetlinks.json` with package `xyz.imprest.app` and the signing certificate's SHA-256	`web/public/.well-known/` (I generate it from the debug or release keystore)	$0
`ios.associatedDomains: ["webcredentials:<domain>"]`	`app/app.json` (currently the placeholder `webcredentials:imprest.example`)	$0
`EXPO_PUBLIC_PASSKEY_RP_ID=<domain>`	`app/.env`	$0
`NEXT_PUBLIC_PASSKEY_RP_ID=<domain>`	web host environment variables	$0
Android development build: `cd app && npx expo run:android`	Android Studio on this PC, phone over USB	$0
iOS development build: `npx expo run:ios`, or `eas build --profile development`	needs a Mac with Xcode, or an Expo account for cloud builds	Apple Developer Program, $99 per year

Owner steps: (1) buy or choose a domain, (2) deploy web/ to it, (3) send me the domain, plus the Apple Team ID if you want iOS, (4) I fill in the files above and rebuild, (5) run the development build on your phone. Android alone costs only the domain. Nothing has been bought or signed up for on your behalf.

What a device run needs (owner)

Passkey domain. Mera passkeys on iOS/Android require the app to be associated with the

relying-party domain: host the web app on a domain you own, serve /.well-known/apple-app-site-association (webcredentials, team id + xyz.imprest.app) and /.well-known/assetlinks.json (package xyz.imprest.app + signing cert SHA-256), set that domain in app.json (ios.associatedDomains) and EXPO_PUBLIC_PASSKEY_RP_ID.

A development build, because react-native-passkey is a native module (not Expo Go):

npx expo run:android (Android Studio) or npx expo run:ios (Xcode, Apple developer account), or eas build --profile development (Expo account).

A little testnet MON on the derived address for gas.

Until then the app shows RP_ID_NOT_CONFIGURED instead of pretending to sign in.

Known limitation: pending transactions across an app restart

The native app follows the same rules as the website:

a transaction whose receipt is late is shown as "Submitted, outcome not yet known", never as failed;
no new transaction is sent while one is unresolved;
verification compares the receipt block and the signed fill on two RPCs.

The record of an unresolved transaction is kept in memory only. It survives moving between screens but not an app restart: the native build has no storage module (adding one, such as @react-native-async-storage/async-storage, needs a new native dependency and a development build). After a restart, check the transaction on the explorer before sending the same order again. The website keeps this record in browser storage and does survive a reload.