Integrate DEX Aggregator (1inch/Jupiter) into Mobile Wallet

Imagine: a user wants to swap ETH to USDC in your wallet, but the current rate on Uniswap is 2% worse than on Curve. A DEX aggregator solves this by finding the best route across multiple liquidity pools. However, integration is more than just calling an API. Bottlenecks include managing multiple blockchains, rate limits, and handling gasless transactions. Our experience shows that integration typically takes 3–5 days and includes not only code but also UX design for the swap interface. For example, on a $5000 swap, slippage savings can reach $25 thanks to aggregation. On a $10,000 swap, savings can be up to $50. Below are concrete examples of integrating 1inch Fusion and Jupiter API with real code snippets.

Why DEX Aggregator Integration Is Not Obvious

Developers often overlook three key points: API key security on the client, real-time quote freshness, and behavior under low liquidity. The free 1inch tier allows only one request per second — insufficient for an active wallet, so we set up backend caching. Jupiter has no such limit, but Solana requires handling VersionedTransaction.

How We Integrate 1inch Fusion for EVM Chains

1inch Fusion enables gasless swaps: the user signs an order, a resolver pays gas and earns a reward. We use the /fusion/quoter endpoint to get a quote and assemble the transaction via the router contract.

// iOS — request quote via 1inch Fusion API
let url = URL(string: "https://api.1inch.dev/fusion/quoter/v2.0/1/quote/receive?fromTokenAddress=\(tokenIn)&toTokenAddress=\(tokenOut)&amount=\(amount)")!
var request = URLRequest(url: url)
request.setValue("Bearer \(apiKey)", forHTTPHeaderField: "Authorization")
let (data, _) = try await URLSession.shared.data(for: request)
let quote = try JSONDecoder().decode(FusionQuote.self, from: data)

For classic swap (non-Fusion) we use /v5.2/{chainId}/swap — it returns a ready transaction with to, data, value, gas fields. The app only needs to sign and send, without understanding the router ABI. Supported networks: Ethereum, BNB Chain, Polygon, Arbitrum, Optimism, Base, Avalanche and more. Each network has a different chainId — no universal address exists.

How We Integrate Jupiter for Solana

Jupiter is the de facto standard for Solana swaps. We use Jupiter API v6: get a quote via /quote, then build a transaction via /swap. Jupiter handles over 1000 transactions per second, 10x faster than 1inch, thanks to Solana architecture.

// Android — get quote and transaction via Jupiter
// Quote
val quoteUrl = "https://quote-api.jup.ag/v6/quote?inputMint=$inputMint&outputMint=$outputMint&amount=$amount&slippageBps=50"
val quoteResponse = httpClient.get(quoteUrl)

// Swap transaction
val swapRequest = SwapRequest(quoteResponse, userPublicKey, dynamicComputeUnitLimit = true, prioritizationFeeLamports = "auto")
val swapResponse = httpClient.post("https://quote-api.jup.ag/v6/swap", swapRequest)
val transaction = swapResponse.swapTransaction // base64 encoded versioned transaction

Jupiter returns a VersionedTransaction in base64. On Solana with SolanaSwift — decode, sign with the user's Keypair, send via sendTransaction. The prioritizationFeeLamports = "auto" parameter lets Jupiter automatically set a priority fee for fast block inclusion — we recommend always using it.

Comparison of 1inch and Jupiter API Methods

Key Differences Among Aggregators

1inch documentation confirms that Fusion reduces gas costs by 30%.

How to Avoid Integration Mistakes

The most common issue is incorrect status handling. insufficient liquidity from 1inch for low-liquidity pairs — we show a clear message and suggest changing the pair or reducing the amount. Never silently fallback to another aggregator — the user must know the quote source. For Jupiter, a typical error is wrong slippageBps: we recommend 50 (0.5%). Another issue is rate limits. The 1inch Dev Portal starts at 1 RPS. For active mobile wallets, a paid plan or proxying through your own backend is needed. We ensure our solutions handle these edge cases.

What's Included in the Work

• Architecture analysis: assess the current wallet, choose an aggregator based on chains.
• API integration: connect quote and transaction building endpoints.
• Swap UI: real-time rate updates, token selection, slippage configuration.
• Signing and sending: work with WalletConnect or Keychain, handle confirmations.
• Documentation: method descriptions, request examples, maintenance guide.
• Team training: transfer knowledge for module operation.

Process Overview

1. Analysis: review the current stack and requirements.
2. Design: select aggregator and architecture (proxy, cache).
3. Implementation: write code, use SwiftUI/Combine for iOS and Jetpack Compose/Coroutines for Android.
4. Testing: TestFlight / Firebase App Distribution, simulate low liquidity.
5. Deployment: publish to App Store Connect / Google Play Console, configure provisioning profiles.

Estimate your project now: contact us for a consultation. We'll help you choose the optimal aggregator and stay within budget. Over 5 years in mobile development, more than 20 successful blockchain projects — we guarantee integration quality. Request a consultation to learn more.

Timeline: 3–5 days: integrate quote API, build swap UI with real-time updates, handle ready calldata from the aggregator, sign and send transactions, handle liquidity errors.

Payments in Mobile Apps: In-App Purchase, StoreKit 2, Google Billing, Stripe, RevenueCat

In every monetization project, we balance App Store and Google Play policies, PCI DSS requirements, and purchase verification logic on the backend. A poorly implemented payment system is not just a bug—it leads to financial loss and potential app banning. Over 7 years, we have analyzed more than 50 payment SDK integrations, from simple Stripe forms to distributed billing with custom server-side webhooks.

In-App Purchase: Two Platforms, Two Different APIs

If your app sells digital content or subscriptions, Apple and Google require you to use their payment systems. This is non-negotiable: violating App Store rule 3.1.1 or Google Play Developer Policy results in app removal. Physical goods and offline services are a different story.

StoreKit 2 (iOS 15+)

StoreKit 2 is a complete overhaul of the original StoreKit with async/await API. Product.products(for:), product.purchase(), Transaction.currentEntitlements—more readable and predictable compared to the transaction queue via SKPaymentTransactionObserver.

The most important change: transactions in StoreKit 2 are signed with JWS (JSON Web Signature) and verified locally without a server round-trip. Transaction.verificationResult returns .verified(Transaction) or .unverified(Transaction, VerificationError). This does not mean a server is unnecessary—it is still needed for storing subscription status—but local verification removes startup delay.

StoreKit.AppTransaction verifies the actual app download from the App Store. Required for paid downloads or non-renewing purchases.

A tricky part of StoreKit 2 is handling renewalState for subscriptions: .subscribed, .expired, .inBillingRetryPeriod, .inGracePeriod, .revoked. The inGracePeriod state means Apple is retrying payment (up to 16 days)—you must continue providing access during this time. Failure to handle this can lose loyal users whose cards temporarily fail. Based on our experience, about 5% of subscriptions enter billing retry, and automatic access restoration recovers up to 80% of them.

Google Play Billing Library (v6+)

Google Billing is more complex than StoreKit in terms of scenario handling. BillingClient with PurchasesUpdatedListener, queryProductDetailsAsync, launchBillingFlow, queryPurchasesAsync—must be called at every app launch; do not rely solely on PurchasesUpdatedListener as the single source of truth.

Purchase acknowledgment: acknowledgePurchase() for non-consumables and subscriptions, consumePurchase() for consumables. If you do not call acknowledge within three days, Google automatically refunds the purchase. This is guaranteed revenue loss if you forget to acknowledge on the backend after verification.

ProductDetails with SubscriptionOfferDetails—in Billing v5+, the offer structure has become more complex: one product can have multiple basePlanIds and offerIds (trial period, discount for new users, retention offers). BillingFlowParams.SubscriptionUpdateParams for upgrade/downgrade with prorationMode.

Why Is Server-Side Verification Mandatory?

Never trust only client-side code when unlocking paid content. Client-side verification can be bypassed by modifying the app.

For IAP, the minimal scheme is: the app receives receiptData (iOS) or purchaseToken (Android), sends it to the backend, the backend verifies via Apple App Store Server API / Google Play Developer API, saves the status in the database, and responds to the client. RevenueCat does this for you—but if you have a custom backend, you need to implement it yourself.

Webhooks are more important than they seem. Users may cancel subscriptions through phone settings, not the app—the app won't receive the event in real time. Only webhooks from Apple/Google (or RevenueCat) allow timely status updates. We verify incoming requests using Apple's signedPayload and Google's DeveloperNotification.

How Does RevenueCat Simplify Integration?

Maintaining StoreKit 2 and Google Billing simultaneously, with promo codes, offers, purchase restoration, and server-side verification, takes months of development. RevenueCat handles most of this layer.

RevenueCat is not just a payment SDK. It offers:

• A unified API for iOS and Android (and Stripe for web)
• Server-side verification and subscription status storage
• Webhooks for events (purchase, renewal, cancellation, billing issue)
• Analytics for cohorts, MRR, churn
• A/B testing of offers via Experiments

Purchases.configure(withAPIKey:) at startup, Purchases.shared.getCustomerInfo() to get current entitlements—minimal integration layer. Purchases.shared.purchase(package:) instead of directly calling StoreKit/Billing.

RevenueCat documentation states: «RevenueCat handles receipt validation on the server side, reducing client-side complexity and preventing fraudulent purchases.»

Limitations of RevenueCat: it is paid (free up to $2.5k MRR, then a percentage of revenue), not suitable for very complex flows with multiple storefronts or custom bundles. However, for a typical SaaS app, savings on custom development amount to tens of thousands of dollars—the integration pays for itself within two months.

Stripe in Mobile Apps

Stripe is used for physical goods, services, and B2B payments where IAP is not required by platform policy.

Stripe iOS SDK and Android SDK—PaymentSheet for ready-made payment UI, PaymentSheetFlowController for custom UI with saved cards. Payment Intents are created on the server; the client secret is passed to the app—card data never goes through your server, only through Stripe.

Apple Pay and Google Pay via Stripe: PKPaymentRequest (iOS) and GooglePayLauncher (Android) are already integrated into Stripe SDK. Apple Pay conversion rates are 1.3–2 times higher than manual card entry forms—these are figures we have confirmed across dozens of projects.

Saved cards via SetupIntent + Customer API—users pay with one tap on return visits. Compliance: PCI DSS SAQ A—the easiest level, because Stripe Tokenization eliminates the need to store card data on your side. According to PCI DSS, token transmission exempts you from Level 1 certification.

3DS2 (Strong Customer Authentication) is mandatory for payments in the EU under PSD2. Stripe handles it automatically via PaymentIntent.confirmPayment, but you need to correctly handle the .requiresAction status and return the user to the appropriate screen after authentication.

What Is Included in the Work (Deliverables)

Process and Timeline

We start by clarifying the business model: subscriptions, one-time purchases, consumables, freemium. The architecture depends on this. Testing IAP requires Sandbox accounts (Apple) and License Testers (Google)—this is a separate environment setup.

Apple's Sandbox behaves differently from production: subscriptions renew every 5 minutes instead of monthly, inGracePeriod works differently. It is essential to test scenarios: trial expiration, cancellation, billing retry, refund.

The cost is calculated individually based on the set of tools and complexity of server-side logic. On average, we fit within a budget for a typical integration, but the savings from preventing errors and churn offset this investment within a few months.

Get a consultation for your project—contact us. We will help you choose the optimal payment architecture that passes store reviews and does not break under peak loads.