#payment and billing integratio

Adapty.io

One-stop solution with open-source SDK for mobile in-app subscription integration to iOS, Android, React Native, Flutter, Unity, or web app. Free up to $10k monthly revenue.

Currencyapi

Free currency conversion and exchange rate data API. Free 300 requests per month, 10 requests per minute for private use.

CurrencyApi

Live Currency Rates for Physical and Cryptocurrencies, delivered in JSON and XML. The free tier offers 1,250 API requests/month.

CurrencyFreaks

Provides current and historical currency exchange rates. Free DEVELOPER plan available with 1000 requests/month.

currencylayer

Reliable Exchange Rates and Currency Conversion for your Business, 100 API requests/month free.

exchangerate-api.com

An easy-to-use currency conversion JSON API. The free tier updates once per day with a limit of 1,500 requests/month.

FxRatesAPI

Provides real-time and historical exchange rates. The free tier requires attribution.

ParityVend

Automatically adjust pricing based on visitor location to expand your business globally and reach new markets (purchasing power parity). The free plan includes 7,500 API requests/month.

Qonversion

All-in-one cross-platform subscription management platform offering analytics, A/B testing, Apple Search Ads, remote configs, and growth tools for optimizing in-app purchases and monetization. Compatible with iOS, Android, React Native, Flutter, Unity, Cordova, Stripe, and web. Free up to $10k in monthly tracked revenue.

RevenueCat

Hosted backend for in-app purchases and subscriptions (iOS and Android). Free up to $2.5k/mo in tracked revenue.

vatlayer

Instant VAT number validation and EU VAT rates API, free 100 API requests/month