Afex
The AFEX API is designed for businesses that want to connect their existing software or ERP infrastructure to AFEX's extensive range of international payment, risk management and FX services. By accessing AFEX's Payment Engine via our API, it allows our partners to automate their end-to-end payment processes and rapidly deliver direct tailor-made solutions for their business requirements. Payments are sent through AFEX’s intermediary banks, payment channels and are bound by applicable laws, regulations, clearing house rules or payment processing procedures. Our API is built by developers for developers making it straightforward to integrate with our systems. Rest assured that all new clients who wish to partner with AFEX and integrate with our API will also be designated their own IT Programme Manager to assist throughout the whole integration life-cycle. We’ve designed our documentation to be easy to use as well as providing a clear insight into AFEX's suite of API services. All of our individual API methods are grouped into feature sets which you can see in the navigation menu here on our API documentation.
Paypal Commerce API
We're designing PayPal Developer to better help you implement end-to-end payment solutions. Instead of a series of products, we're introducing a platform experience with PayPal Commerce Platform. For over 20 years, PayPal has focused on creating powerful tools to drive global commerce. We serve over 300 million consumers and 20 million sellers around the world.

Viafintech
The name viafintech refers to the company viafintech GmbH. The names Barzahlen and viacash refer to the same product. Viafintech API v2 allows you to create payment, partial payment, payout, and refund slips customers can use in stores like supermarkets to pay or receive money. Slips are sent to users as an email with a PDF attachment or as a text message. When a store's point of sale system confirms the transaction, viafintech usually immediately calls a Webhook to notify your system about the payment. You can then use this confirmation e.g. to mark an invoice as paid or trigger shipping goods to the customer. The name viafintech refers to the company viafintech GmbH. The names Barzahlen and viacash refer to the same product.

mastercard
It is official api of Mastercard. It lets you create custom payment solutions for your website needs. For example, you can :— - provide consumer friendly merchant details for every transaction. - deliver an entirely digital end-to-end payment experience - parents can use their conversational device to send funds and set spending limits - find contactless merchants on-the-go - build a cashless solution for any parent whose child goes to school using public transport - instantly and securely make payments to your workers and - get updated card information in real-time

Square
Build customized solutions that accept payments (online, in-person, or in-app), manage products and customers, and handle the day-to-day operations that keep business running. Square APIs are powerful, secure, reliable, and free to use. Square APIs enable you to accept payments securely and integrate your app with Square’s first party product ecosystem. Build full-featured business apps for yourself or millions of Square sellers. Our API Reference is organized around core business workflows: taking payments, managing orders, syncing items and inventory with Square Point of Sale, creating customer records, managing business locations, and enabling Square sellers to use your app. Connect your app to our secure and PCI-compliant platform to accept payments in person, in an app, or online. Take orders via web and mobile applications and send them directly to Square Point of Sale or your own custom application. Enable fast and flexible catalog management, including individual and batch support for retrieval, updates, and deletion. Leverage customer data to create applications that help sellers grow their sales and build customer loyalty. Make better supply chain decisions by creating tools to improve inventory management. Integrate timekeeping or collaboration tools that support sellers and help maintain their high performing teams.

Braintree
Accept and process cards, wallets, and Local Payment Methods in a single, modern integration. Store customer and payment information to reduce friction at checkout. Build a payment form with the right level of customization for your needs. Add payment methods your customers want to your checkout. Securely store customer information – including payment method information.

PayRequest API
API to create payment links
Finnhub Stock API
Access real-time stock API, institutional-grade fundamental and alternative data to supercharge your investment for FREE.

Stripe API
Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes.

World Trading Data
Get access to the best worldwide market data provider with API.
Baremetrics
Baremetrics offers simple integration with popular payment providers such as Stripe, Recurly and Braintree.

bunq API
Open bank RESTful API with a cross-EU licence. Work with cards, accounts, payments and more
Tradier
US equity/option market data (delayed, intraday, historical)
Financial Modeling Prep
Free stock, historical data, financial statements API
Alpha Vantage
Realtime and historical stock data
IG Labs
Automate trades, build integrations and create trading apps using our market-leading CFD and spread betting technology.
Plaid
Enables applications to connect with users’ bank accounts and access transaction data

CoinMarketCap
Cryptocurrencies Prices simple API

CryptoCompare
Cryptocurrencies Comparison API
IEX
Stocks and Market Data on IEX Cloud

Razorpay IFSC
Indian Financial Systems Code (Bank Branch Codes)
CoinDesk
CoinDesk provides a simple API to make its Bitcoin Price Index (BPI) data programmatically available to others.