NFT Minting in Mobile Apps: Full Cycle Development

We integrate NFT minting directly into mobile apps for iOS and Android. This involves uploading media to IPFS, generating correct ERC-721 metadata, and calling a smart contract — all while handling connectivity drops and memory constraints on the phone. We have delivered over 15 projects with NFT integration, including connections to major marketplaces, and have accumulated practical solutions to these problems.

Our experience spans Ethereum, Polygon, and Solana networks, working with IPFS via Pinata and NFT.Storage, as well as setting up push notifications for transaction statuses. Lazy minting lets you postpone gas payment until the moment of sale, saving up to 90% of costs compared to regular minting — that's 10 times more profitable for the creator. In this article we will break down the technical details of each stage so you can avoid typical mistakes and make minting convenient for the user.

How to Mint NFT from a Mobile Device?

Minting in a mobile app goes through three stages: selecting and uploading the media file, generating ERC-721 metadata, and sending the transaction to the blockchain. Each stage has its own pitfalls.

Uploading Media to IPFS

For storing media we use the decentralized storage IPFS. On iOS we use PHPickerViewController (available since iOS 14), on Android — PhotoPicker (Android 13) with a fallback to GetContent. The file is sent to the Pinata or NFT.Storage API. Here's an example upload in Swift:

// iOS — upload file to Pinata IPFS
func pinFileToIPFS(fileURL: URL, fileName: String) async throws -> String {
    var request = URLRequest(url: URL(string: "https://api.pinata.cloud/pinning/pinFileToIPFS")!)
    request.httpMethod = "POST"
    request.setValue("Bearer \(pinataJWT)", forHTTPHeaderField: "Authorization")

    let boundary = UUID().uuidString
    request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")

    var body = Data()
    body.append("--\(boundary)\r\nContent-Disposition: form-data; name=\"file\"; filename=\"\(fileName)\"\r\n")
    body.append("Content-Type: image/jpeg\r\n\r\n")
    body.append(try Data(contentsOf: fileURL))
    body.append("\r\n--\(boundary)--\r\n")
    request.httpBody = body

    let (data, _) = try await URLSession.shared.data(for: request)
    let response = try JSONDecoder().decode(PinataResponse.self, from: data)
    return "ipfs://\(response.ipfsHash)"
}

For large files (video from 100 MB) we configure background upload via URLSession with background configuration on iOS and WorkManager with setExpedited on Android. We display progress as a bar and notifications. Average gas fee for minting on Ethereum 0.05 ETH ($100 at current rates), on Polygon — less than $0.01, which makes Polygon 10,000 times cheaper.

Generating ERC-721 Metadata

After uploading the media, you need to generate JSON metadata according to the OpenSea standard. Example in Kotlin:

// Android — forming NFT metadata JSON
data class NftMetadata(
    val name: String,
    val description: String,
    val image: String,        // ipfs://QmXxx... (CID of uploaded file)
    val externalUrl: String?,
    val attributes: List<NftAttribute>
)

data class NftAttribute(
    val traitType: String,
    val value: String
)

// Example result
val metadata = NftMetadata(
    name = "My NFT #1",
    description = "Created via mobile app",
    image = "ipfs://QmImageHash...",
    attributes = listOf(
        NftAttribute("Background", "Blue"),
        NftAttribute("Rarity", "Rare")
    )
)

This JSON is uploaded to IPFS, and the resulting URI is passed to the mint function of the smart contract. We automate attribute generation — the user can add key-value pairs in the interface.

Minting UI Form

The form includes fields: name, description, media, attributes. Real-time NFT preview. The process is broken into three steps with indicators:

1. Upload media to IPFS
2. Upload metadata
3. Minting transaction

Progress is shown at each step. Errors (e.g., insufficient gas) are handled with clear messages.

Why Lazy Minting is Beneficial for Creators?

High gas fees are the main barrier for creators. Lazy minting allows postponing writing the token to the blockchain until the first sale. Instead of an immediate transaction, the creator signs an EIP-712 voucher containing the price and metadata URI. The buyer activates minting at purchase and pays the gas. Lazy minting is 10 times more cost-effective than regular minting for creators.

Comparison of the two approaches:

We recommend lazy minting for marketplaces and collections with low sales volume. Gas savings can reach 90%.

Our Work Process for Minting Integration

1. Analysis — define NFT requirements: standard (ERC-721/1155), network (Ethereum, Polygon, Solana), gas payment methods.
2. Design — develop architecture: choose IPFS provider, metadata schema, wallet integration (WalletConnect or embedded).
3. Implementation — write minting module: media selection, IPFS upload, metadata generation, contract call. For lazy minting add signing and voucher verification.
4. Testing — check on testnet (Goerli, Mumbai), simulate connection drops, test with different file sizes.
5. Deployment — publish to App Store and Google Play, integrate with backend if needed.

Stages and timelines:

What Is Included in the Deliverable

• Source code of the minting module (iOS Swift, Android Kotlin)
• Integration with IPFS (Pinata or NFT.Storage)
• Documentation for smart contract and API
• Push notification setup for transaction status
• Administration guide (provider change, contract update)
• 30-day support after delivery
• Training session for your team (up to 2 hours)

Timeline

The project takes from 5 to 10 working days depending on complexity: basic minting — 5 days, with lazy minting — up to 8 days, with multi-network support — up to 10 days. Contact us for an accurate estimate of your case.

We guarantee compatibility with App Store and Google Play rules, as well as full documentation for independent further development. Order minting development — get a ready-made module in 5-10 days.

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.