Payment and Billing Integration

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.

Real-time mid-market exchange rates for 150+ currencies with official JavaScript, Python, and PHP SDKs. Free tier includes 300 requests/month over HTTPS.

Real-time crypto and prediction market data API for pricing, charts, transactions, wallet balances, and trending data. The free tier offers 10,000 requests for free per month, with credit card or crypto authentication required.

Cancel flows (open-sourced), churn metrics, and revenue analytics for subscription businesses. Free forever.

Provides cryptocurrency market data including the latest crypto and fiat currency exchange rates. The free tier offers 10K call credits/month.

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

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

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

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

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

Real-time currency rates for 160+ currencies with 60-second updates and official SDKs. Free tier includes 300 requests/month.

Help merchants to prevent payment fraud and chargebacks. Free Micro Plan available with 500 queries/month.

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

Generate revenue from APIs via usage-based billing. Connect to Stripe, Chargebee, etc. The free tier offers 30,000 events/month.

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.

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.

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

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