Staking Integration for Mobile Wallets
Token staking integration requires careful risk management. We ensure token staking is simple and secure. A user wants to earn income from their tokens without leaving the mobile app. But staking is an operation with asset locking: if you make a mistake with the validator or don't account for the unbonding period, funds can be frozen for weeks. Also, gas fees can be significant during peak hours, and a wrong validator choice risks slashing. We integrate staking so that the user sees all risks before confirmation, and the process is as automated as possible.
Why Choose Liquid Staking?
Liquid staking (Lido, Rocket Pool, Jito) solves the main problem of native staking: the minimum deposit. On Ethereum, native requires 32 ETH — for a mobile wallet this is unaffordable. Liquid staking provides a 100x lower entry threshold (0.01 ETH vs 32 ETH). The user can deposit any amount, receiving a liquid token (stETH, rETH, jitoSOL) that increases in price relative to the base asset. Liquid staking is 10 times more convenient than native staking for mobile users, as it does not require choosing a validator.
Compare the two approaches in the table:
| Parameter |
Native staking |
Liquid staking |
| Minimum amount |
32 ETH (ETH) / 0.01 SOL (Solana) |
0.01 ETH / 0.0001 SOL |
| Unbonding period |
Instant (ETH) / 2 epochs (Sol) / 21 days (Cosmos) |
Instant (exchange trading) |
| Rewards |
Manual claim every epoch |
Automatic token rebalancing |
| Protocol fee |
0% |
5-10% of rewards |
| Risks |
Validator slashing |
Smart contract vulnerability |
How We Integrate Staking
Steps for Lido (Ethereum) integration:
- Connect to the Lido smart contract via Web3.
- User enters an ETH amount.
- Call
submit(referral) method, passing the ETH value.
- Returned stETH is displayed in the balance.
Code example in Swift and Kotlin
```swift
// iOS — staking ETH via Lido
let lidoContract = EthereumContract(json: lidoABI, at: lidoAddress)
let submitFunction = lidoContract.method(
"submit",
parameters: [referralAddress as AnyObject],
transactionOptions: .init()
)
// value = ETH amount for staking
```
For Solana we use Jito SDK: stake(validatorIndex, amount) or Marinade Finance. Native Solana staking via delegation:
// Android — delegating SOL to validator via SolanaKT
val stakeAccount = Keypair.generate()
val createStakeAccountInstruction = SystemProgram.createAccount(
fromPublicKey = walletPublicKey,
newAccountPublicKey = stakeAccount.publicKey,
lamports = amountLamports + rentExemptLamports,
space = StakeProgram.STAKE_ACCOUNT_SIZE,
programId = StakeProgram.PROGRAM_ID
)
val delegateInstruction = StakeProgram.delegate(
stakePublicKey = stakeAccount.publicKey,
authorizedPublicKey = walletPublicKey,
votePublicKey = validatorVoteAccount
)
Epoch on Solana ≈ 2–3 days. Stake activates in the next epoch. Unstake — also one epoch cooldown, then withdraw.
How We Ensure Staking Security
We use only verified smart contracts from leading protocols (Lido, Jito, Rocket Pool) with open source code and audits. The code is signed, private keys are not stored on the device. Before deploying to mainnet, we conduct full unit testing and operation simulation on testnet. According to Lido documentation, the minimum staking amount is 0.01 ETH.
Scope of Work
- Requirements analysis and protocol selection (Lido, Jito, Marinade, Rocket Pool) based on your audience and network.
- Smart contract integration: connecting via RPC, loading ABI, testing stake/unstake functions.
- User interface development: screens for amount entry, validator selection, confirmation, and active stake status.
- Error handling: dealing with gas errors, insufficient balance, transaction rejections.
- Testing on testnet and mainnet, including edge cases (minimum amounts, long unbonding).
- Documentation and support team training.
Our solution reduces fees by up to 3 times compared to self-integration. Integration pricing starts from $5,000 for a single protocol (e.g., Lido). Contact us for an exact quote.
What's Included in Integration?
- Smart contract integration (Lido, Jito, Rocket Pool) with ABI verification and testnet testing.
- Validator selection UI: table with APY, commission, 30-day uptime.
- Confirmation screen showing unbonding period and final amount after staking.
- Active stake display: stETH/jitoSOL balance, accumulated rewards, progress bar to unbonding.
- Unstake button with countdown timer for networks with cooldown.
- 'Awaiting Unlock' section with amount and remaining time.
- Documentation and support team training.
Estimated Timeline
| Stage |
Duration |
| Analysis and protocol selection |
1-2 days |
| Single contract integration (RPC, ABI, functions) |
2-3 days |
| Staking UI (amount entry, validator selection) |
1 day |
| Active stake and unstake UI |
1 day |
| Testing (unit, integration, QA) |
2-3 days |
| Deployment and release (App Store/Google Play) |
1-2 days |
Integrating a single protocol (e.g., Lido or Jito) takes from 5 days turnkey: from contract to unstake UI. If you need to connect multiple networks (Ethereum + Solana + Cosmos) or add liquid staking with exchange, the timeline extends to 2-3 weeks. Pricing is calculated individually for your project. Contact us to get a precise estimate.
Our team has 5+ years of experience in mobile crypto wallet development and has implemented over 30 staking projects. We guarantee compliance with App Store Review Guidelines (Section 4.2/5.1) and no key leaks. Order staking integration — get a consultation from an engineer within a day.
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)
| Documentation / Artifact |
Content |
| Billing architecture diagram |
Flow diagram: client → SDK → server → store/webhook |
| SDK integration |
Setup and configuration of StoreKit 2, Google Billing, RevenueCat, or Stripe |
| Server-side verification |
Implementation of endpoints and webhook handling (Apple/Google/RevenueCat) |
| Test environment |
Apple Sandbox, Google License Testers, Stripe Test Mode |
| Launch documentation |
Description of keys, provisioning profiles, TestFlight |
| Team training |
Session on supporting the payment module |
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.
| Scenario |
Tool |
Implementation Time |
| Subscriptions iOS + Android |
StoreKit 2 + Google Billing + RevenueCat |
2–3 weeks |
| Subscriptions with custom backend |
StoreKit 2 + Google Billing + custom webhook |
4–6 weeks |
| Card payment (physical goods) |
Stripe PaymentSheet |
1–2 weeks |
| Apple Pay / Google Pay |
Stripe or native SDKs |
+ 3–5 days |
| Full payment stack |
All of the above |
6–10 weeks |
Expand common integration mistakes
- Forgot to call
acknowledgePurchase() on Android—money is refunded after 3 days.
- Did not handle
inGracePeriod—loyal users are blocked from access.
- Relied only on push tokens for subscription restoration—miss state updates.
- Used production keys in TestFlight—real charges occur.
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.
