5 Best iOS External Payment SDKs for App Developers in 2025
Summary
- The Epic v. Apple ruling allows US-based iOS apps to bypass Apple's 30% commission, but choosing the right payment tool is critical to avoid high engineering costs and low conversion rates.
- Tools like RevenueCat and Adapty only analyze existing App Store subscriptions; they do not process direct payments or help you migrate users off Apple's billing system.
- Stripe provides payment processing but requires you to build all tax compliance, subscription logic, and migration infrastructure yourself, while web-first platforms like Paddle often rely on web redirects that hurt mobile conversion.
- For developers looking to reclaim margin without months of engineering, Allocents offers a purpose-built SDK that handles native UI, tax compliance (as a Merchant of Record), and subscriber migration campaigns in a 15-minute integration.
The April 2025 Epic v. Apple ruling changed everything. For the first time, US developers can legally offer external payment options in their iOS apps without being forced through Apple's In-App Purchase (IAP) system — unlocking access to a $150B+ annual market that Apple had effectively locked behind a 30% commission.
But freedom isn't the same as simplicity. If you've been lurking in developer communities, you've already seen the anxiety play out in real time:
"Managing payments outside of Apple's ecosystem introduces significant complexity and potential issues."
"Switching to external payment systems typically leads to lower conversion rates for purchases."
"The additional cost and distraction from your app doesn't make sense unless you're very large."
These are legitimate concerns. The problem is that developers are often comparing tools that aren't actually solving the same problem. Allocents, RevenueCat, Stripe, Paddle, and Adapty get mentioned in the same breath — but they do fundamentally different things, and picking the wrong one means you either end up back at square one or you spend months building infrastructure that should have come out of the box.
This guide gives you an honest, technical breakdown of each tool: what it actually does for iOS external payments, what it doesn't handle, pricing, and who it's really built for.
1. Allocents — The Purpose-Built iOS Migration SDK
Allocents is the only tool in this list built specifically for the post-Epic challenge: migrating iOS subscribers from StoreKit to direct billing without destroying your conversion rates or drowning your team in compliance work.
Allocents was built from the ground up to solve this new challenge, understanding that bolting web payment tools onto a native mobile experience was a recipe for failure.
What it actually does for external iOS payments
Allocents provides a single SDK (Swift/SwiftUI, Kotlin, Flutter, React Native) that drops into your existing app in approximately 15 minutes. It handles every layer of the migration stack:
- Sign Up & Save paywalls — New users see a choice between standard App Store pricing and a discounted direct billing option. Native UI, no webview redirects.
- Switch & Save campaigns — Intelligent offers targeted at your existing StoreKit subscribers to migrate them to direct billing at a lower price point.
- Native web checkout — An embedded payment sheet with Apple Pay support that feels like a first-party experience.
- Automatic StoreKit product sync from App Store Connect, so you're not manually re-entering your entire product catalog.
- Gradual rollout — Start showing the direct billing option to 10% of users, measure conversion and revenue impact, then dial it up. Instant rollback if needed.
- Jurisdiction-aware routing — Only surfaces direct billing in regions where it's legally permitted (US-first, expanding globally).
- Analytics dashboard — Tracks migration rates, cohort adoption, and revenue impact in real time.
Allocents offers two billing modes:
- Allocents Billing (Merchant of Record): Allocents acts as the full MoR — handling payments, global tax remittance across 190+ countries, chargebacks, fraud protection, and customer support. This is the plug-and-play option for teams that don't want to touch tax compliance.
- Bring Your Own Stripe (BYOS): Connect your existing Stripe account. You remain the MoR and handle chargebacks and compliance; Allocents provides the SDK, native UI flows, and migration campaigns.
What it does NOT handle
Allocents is laser-focused on iOS direct billing migration. It's not an all-in-one platform for web subscription billing or B2B SaaS invoicing.
Pricing
- Allocents Billing (MoR): 5% + 50¢ per transaction
- BYOS: 0.5% of direct billing revenue migrated via Allocents' flows
Target developer profile
Mobile-first app developers with $500K–$20M+ ARR who are serious about reclaiming margin. Ideal for mobile gaming (consumables: coins, gems) and subscription apps (fitness, media, productivity, dating) on Swift/SwiftUI, Kotlin, Flutter, or React Native.
2. RevenueCat — The Subscription Management Backend
RevenueCat is not a payment processor, and it's not a StoreKit alternative. It's a powerful backend service that sits on top of payment systems like StoreKit or Google Play Billing, simplifying subscription management across platforms.
What it actually does for external iOS payments
RevenueCat automates receipt validation, manages subscription states (active, expired, in trial), and gives you a unified view of subscriber data across iOS, Android, and web. It's used by over 30,000 apps and has tracked over $5 billion in revenue. Its paywall templates and A/B testing tools can meaningfully improve your IAP conversion rates.
What it does NOT handle
RevenueCat does not process payments and does not offer a direct billing checkout experience. You cannot use RevenueCat alone to bypass Apple's IAP — it is a management and analytics layer, not a gateway. If you want to offer an external payment option for your iOS app, you'll need to pair it with something else.
Pricing
Usage-based. Free up to $2,500 in monthly tracked revenue. Paid plans start at $42/month and scale with revenue.
Target developer profile
Subscription app developers who need a reliable cross-platform backend to manage entitlements and analyze subscriber performance — and who are sticking with StoreKit as their primary payment method.
3. Paddle — The Merchant of Record for Web & SaaS
Paddle is a well-established Merchant of Record platform that handles the full payment lifecycle for software and SaaS companies: payment processing, global VAT and sales tax compliance, invoicing, and subscription management.
What it actually does for external iOS payments
Paddle acts as your MoR, meaning it takes on the legal responsibility for collecting and remitting taxes across jurisdictions. For a web-based SaaS business, this is genuinely valuable. Developers who need to bill customers globally without hiring a tax team often land on Paddle for good reason.
What it does NOT handle
Paddle is web-first. It does not offer a native iOS SDK with purpose-built migration flows for moving users off StoreKit. Integrating Paddle into an iOS app typically means redirecting users to a web-based checkout — which is exactly the pattern that causes conversion rate drops developers fear. There's no Switch & Save campaign tooling, no StoreKit sync, and no gradual rollout mechanism designed for mobile. If your primary distribution channel is the App Store, Paddle isn't solving the iOS migration problem.
Pricing
5% + 50¢ per transaction.
Target developer profile
Primarily software and SaaS companies with a web-first sales strategy who need an all-in-one MoR to handle global tax complexity. Not the right fit for a mobile-native app team trying to move subscribers off StoreKit.
4. Stripe — The Powerful Payment Processing API
Stripe is the gold standard for payment infrastructure flexibility. Its APIs power payment flows for some of the largest platforms in the world, and its iOS SDK provides native UI elements like PaymentSheet and CardElement for collecting payment details directly within an app, including Apple Pay support.
What it actually does for external iOS payments
Stripe gives you the raw primitives to build a direct billing experience. The Stripe iOS SDK on GitHub is mature, well-documented, and actively maintained. If you want to collect a credit card and charge it, Stripe does that better than almost anyone.
What it does NOT handle
Stripe is a payment processor, not a Merchant of Record. This is a critical distinction. With Stripe, you are responsible for calculating, collecting, and remitting sales tax — across every jurisdiction your users are in. You handle chargebacks. You handle fraud. You build subscription logic, entitlement checking, dunning flows, and retention campaigns from scratch. As one developer put it: "Assuming Stripe will manage all aspects of payment processing can overlook additional risks and responsibilities."
Most critically for this use case: Stripe provides zero dedicated iOS migration tooling. There's no concept of Switch & Save campaigns, no StoreKit product sync, no gradual rollout by user percentage. You're looking at a significant engineering investment before you've moved a single subscriber off Apple's billing.
Pricing
Standard pricing is 2.9% + 30¢ per successful card charge, with additional fees for other services.
Target developer profile
Developers and larger engineering teams who require maximum flexibility and are comfortable building and maintaining their own payment infrastructure end-to-end, including tax compliance, subscription logic, and customer support operations.
5. Adapty — The IAP Analytics & Optimization Tool
Adapty is built around optimizing in-app purchase revenue through analytics, A/B testing for paywalls, and user segmentation for targeted promotional campaigns.
What it actually does for external iOS payments
Adapty's strength is data: it helps you understand where your IAP conversion funnel is leaking and run experiments to fix it. Its paywall builder and A/B testing capabilities are genuinely useful for teams that want to squeeze more revenue from their existing StoreKit setup.
What it does NOT handle
Like RevenueCat, Adapty is not a payment processor or a full external billing solution. It provides analytics and optimization tools for your existing IAP strategy and has only partial support for external payment flows — it's not the primary use case the product was designed for. It won't replace StoreKit, manage your tax obligations, or run subscription migration campaigns.
Pricing
Tiered subscription pricing based on features and monthly tracked revenue, with a free tier available.
Target developer profile
Data-driven app developers who want to maximize IAP conversion rates through rigorous experimentation and deep subscriber analytics — and who aren't yet looking to move off StoreKit entirely.
Comparison Table: iOS External Payment SDKs at a Glance
| SDK | Direct Billing | Merchant of Record | Purpose-Built iOS Migration Layer | Pricing | Best For |
|---|---|---|---|---|---|
| Allocents | ✅ Yes | ✅ Yes (or BYOS) | ✅ Yes | 5% + 50¢ (MoR) / 0.5% (BYOS) | $500K–$20M+ ARR iOS developers |
| RevenueCat | ❌ No | ❌ No | ❌ No | Free → $42/mo+ | Subscription management on StoreKit |
| Paddle | ✅ Yes | ✅ Yes | ❌ No | 5% + 50¢ | Web-first software & SaaS |
| Stripe | ✅ Yes | ❌ No | ❌ No | 2.9% + 30¢ | Teams building custom payment infra |
| Adapty | ❌ No | ❌ No | ❌ No | Tiered subscription | IAP analytics & A/B testing |
Choose the Right Tool for the iOS Job
The Epic v. Apple ruling has cracked open a real opportunity, but the risk is picking a tool designed for a different problem entirely and spending months learning that lesson the hard way.
Here's the honest summary:
RevenueCat and Adapty are excellent for managing and analyzing your existing In-App Purchases — not replacing them. If you want to offer an external payment option in your iOS app, neither of these gets you there alone.
Paddle handles MoR complexity beautifully for web and SaaS teams, but its web-first architecture means iOS developers face the same clunky redirect problem that kills conversion rates.
Stripe gives you the most flexibility but front-loads the most engineering work. Tax compliance across 190+ countries, chargeback management, subscription logic, and migration flows — every piece of that is yours to build.
Allocents is the only option reviewed here that was designed from day one for this specific problem: getting iOS subscribers off the 30% Apple tax and onto direct billing, with native UI flows that protect conversion, compliance infrastructure that removes the tax headache, and migration tooling (Switch & Save campaigns, StoreKit sync, gradual rollout) that no competitor has matched.
It’s a comprehensive solution, not just a component, meaning one SDK replaces what would otherwise require stitching together 2-3 different services.
If you're a mobile developer with meaningful ARR and you're serious about reclaiming margin in the post-Epic landscape, explore Allocents and see how Switch & Save campaigns can move your existing subscribers without disrupting their experience.
Frequently Asked Questions
What is the main difference between a Merchant of Record (MoR) and a payment processor?
A Merchant of Record (MoR) is the entity that takes on the financial liability for transactions, including handling global sales tax collection and remittance, managing chargebacks, and ensuring fraud protection. A payment processor, like Stripe, simply facilitates the movement of money. In this article, Allocents and Paddle offer MoR services, removing the tax compliance burden from developers, whereas using Stripe directly means you are the MoR.
Why can't I just use Stripe for external iOS payments?
While Stripe provides powerful and flexible payment processing APIs, it is not an out-of-the-box solution for iOS external billing. Using Stripe directly means you are responsible for building all the surrounding infrastructure from scratch. This includes tax compliance systems for every jurisdiction, subscription management logic, dunning flows for failed payments, and the dedicated tools needed to migrate users from StoreKit without causing churn.
How does Allocents help migrate existing subscribers from Apple's StoreKit?
Allocents is purpose-built to migrate existing iOS subscribers with its "Switch & Save" campaigns. These are intelligent, in-app offers that target your current StoreKit subscribers, encouraging them to switch to direct billing with a discount. The entire process happens within a native UI, avoiding jarring web redirects and preserving the user experience to maximize conversion.
Can I offer direct billing to my iOS users outside of the US?
As of the April 2025 Epic v. Apple ruling, the legal allowance for external payment links is primarily a US-centric development. The regulatory landscape is evolving globally, but for now, offering direct billing is safest and most clearly permitted for US-based users. Solutions like Allocents are jurisdiction-aware and will only surface direct billing options in regions where it is legally compliant.
What is the risk of using a web-based checkout for iOS external payments?
The primary risk of redirecting users to a web-based checkout is a significant drop in conversion rates. This approach breaks the seamless, native app experience that users expect. The added friction of opening a browser, the potential for slow load times, and a less-trusted payment environment often lead users to abandon their purchase. Native payment sheets, like those provided by Allocents, keep the user in the app and feel like a first-party experience.
If I already use RevenueCat or Adapty, how do they work with an external payment solution?
RevenueCat and Adapty are excellent for managing subscription states and analyzing in-app purchase data; they are not payment processors. You can continue to use them alongside an external payment solution. They can help you manage entitlements and track subscriber data across both Apple's IAP and your new direct billing channel, giving you a unified view of your revenue.
What does "Bring Your Own Stripe" (BYOS) with Allocents mean?
"Bring Your Own Stripe" (BYOS) is an Allocents feature that allows you to connect your existing Stripe account for payment processing. With this model, Allocents provides its entire purpose-built iOS migration layer — including native paywalls, Switch & Save campaigns, and StoreKit sync — while you remain the Merchant of Record. This is ideal for larger teams that already have tax and compliance systems in place but want to avoid building the complex iOS-specific migration infrastructure themselves.