Executive summary
Wallet SDKs are the bridge between your application and users’ self-custodial wallets. They let dApps connect, request signatures, and guide users through on-chain flows without ever exposing private keys to the app. This document focuses on architecture, integration patterns, security considerations, developer ergonomics, and migration strategies—drawing from modern implementations (Phantom, Trust Wallet, and common industry patterns).
Why use a Wallet SDK?
Wallet SDKs provide three immediate benefits: (1) **security** — the user retains private key control; (2) **usability** — simplified UX like connect prompts, transaction signing, and deep linking; and (3) **consistency** — standard APIs that reduce integration surface area across browsers and mobile.
Core SDK categories (H4: quick taxonomy)
Browser / Extension SDK
Connects a web app to an existing browser extension wallet (e.g., Phantom extension). Typical features: request connection, read accounts, request signatures, and send transactions. No private keys touch the client app.
React / Frontend SDK
React-focused packages give hooks and components (connect button, modal, network switch helpers). They speed development and promote best practices, handling permission flows and reactivity for account changes.
React Native / Mobile SDK
Mobile SDKs provide deeplinks or embedded wallet experiences; they often include a lightweight runtime to create ephemeral wallets for onboarding or to connect native wallets on mobile.
Server / Custodial SDK
Server SDKs exist for backends that manage keys or implement custodial flows. These require heavy security controls and are generally used only for custodial services, exchanges, or services that perform on-chain batching.
Integration patterns & best practices
A few proven integration patterns produce reliable, secure UX:
- Client-side signing (non-custodial): request signatures using the browser/mobile SDK — ideal for dApps that never hold keys.
- Server-assisted transactions: prepare transactions server-side, send them to client for signing, and let the client submit.
- Deep linking + universal links: essential for mobile web → in-app wallet switching with a seamless UX.
- Fallback flows: implement a “no-wallet” fallback to onboard users (e.g., show instructions or create an ephemeral wallet).
Security: what you must never do
Never request private keys or seed phrases. Never log signature payloads that include sensitive nonce or personal metadata. Always verify the signing payload client-side, and ensure transaction intentions are clearly displayed to users.
Common developer pitfalls
Being reactive to account changes, handling network mismatches, and showing clear error states are often missed. Also, assuming a single wallet API is supported across chains will break multi-chain apps—use adapters and feature checks.
Developer ergonomics: helpful patterns
Feature-detection helpers
Expose a tiny utility: `isWalletAvailable()` and `supportsChain(chainId)` early in your bootstrap. This lets the UI adapt without race conditions.
Example snippet (vanilla)
// detect & connect (pseudo)
async function connectWallet() {
if (!window.phantom?.solana) throw new Error('Phantom not installed');
const resp = await window.phantom.solana.connect();
return resp.publicKey.toString();
}
UX tips for production
Show clear affordances for signing (what action the signature enables), and support cancel/timeout. Use optimistic UI for predictable UX, but always reconcile on-chain after confirmation.
Testing & observability
Add end-to-end tests that simulate disconnected wallets, rejected signatures, and slow confirmations. Instrument key SDK events (connect, disconnect, signRequest, signSuccess, signReject) and track telemetry for failures and latency.
Migration & multi-wallet strategy
If your app initially integrated a single wallet, plan an adapter layer for future expansions (Wallet Adapter pattern). This preserves app code and adds new wallets as plugins—minimizing rework.
Sample section: Implementation checklist (H4 -> steps)
- Pick SDK(s): browser/react/native/server based on your platform.
- Implement feature detection & graceful fallback.
- Implement localized signing prompts and clear transaction summaries.
- Integrate analytics for connect/sign events (PII-safe).
- Test on mainnet/testnet and multiple wallets before release.
Case studies & use-cases
Common dApp flows: NFT checkout (sign payment), staking flows (sign approvals and stake transactions), and token swaps (sign orders). Each flow should show exact token amounts and gas/fee estimates before requesting a signature.
Closing notes
Wallet SDKs are mature, but integrations still require careful handling of UX, security, and cross-device behavior. Architecting with adaptors, error-handling, feature-detection, and clear user intent display will save developer time and user trust.
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