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What We Look For in the Best Credit Card Processing APIs1. Leaders Merchant Services: Low Rates With Multiple API Options2. PAYARC: Robust Free API and International Support3. ProMerchant: Integration With Trusted API for All Kinds of Transactions4. Flagship Merchant Services: Cheap API and High-Risk Merchant Accounts5. Stax: Secure, Well-Documented API for High-Volume Businesses6. Helcim: A Free API for Budget-Conscious BusinessesOther Notable Credit Card Processing APIsWhich Is the Best Credit Card Processing API?FAQ
Short on Time? These Are the Best Credit Card Processing APIs in 2023
- Leaders Merchant Services – Multiple APIs, including Authoize.net and the free Google Pay API, paired with some of the lowest rates in the industry.
- PAYARC – Comprehensive APIs and SDKs and support for international processing.
- ProMerchant – Integration with the trusted Authorize.net API plus a free virtual terminal for processing MOTO payments.
What We Look For in the Best Credit Card Processing APIs
Not every developer kit and API library is built equal. That’s why I made sure every payment API on my list offers these features.- Comprehensive documentation. Having well-written and detailed documentation means you don’t have to spend hours trying to decipher API code, error responses, and access tokens.
- Wide range of supported languages. A well-built API should support multiple programming languages, regardless of the software that will connect to the API. The more languages that a payment processor’s developer kit supports, the better.
- Sandbox. A sandbox lets you test your API in a sandbox environment so you can make sure it works before you deploy it to your working environment. This means you’re not risking harming your customers’ e-commerce experience by testing your API on your live website.
- Security. Because the API will be handling sensitive financial data, the payment processor needs to ensure it is built with a security-first approach. This includes enforcing the use of hashing, SSL certificates, and developer authentication via API access tokens.
- PCI compliance support. Every API offered by a payment processor needs to be PCI-compliant. However, if you’re using the API to build checkouts that are hosted on your website, you’ll have to fill out a different questionnaire to ensure that you’ve met testing and security requirements. Your payment processor should offer support with this.
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Best Credit Card Processor in 2023
Best Credit Card Processor in 2023
Negotiable Low Credit Card Processing Rates
Monthly Fee:
$9
Transaction Fee:
From 2% + 0¢
Pricing Model:
Multiple options
Multiple options
This payment processor allows you to choose from two or more different pricing models for paying credit card processing fees. Each model will come with its own advantages and disadvantages, so make sure to consider your options carefully before deciding which is right for your business.
Features and Benefits
- Pre-built Google Pay buttons. Though you’ll have to adhere to Google Pay’s branding standards to use its API, you can customize the Google Pay button that appears on your site. You can change text, language, color, and sizing before copying and pasting the code directly into your website.
- Only pay for what you need. Because Authorize.net is available at an additional cost, you don’t have to pay for it if it doesn’t suit your business.
- Built-in QuickBooks integration. While you won’t be able to build custom integrations with LMS directly, it does offer a QuickBooks integration that allows you to sync your accounting data.
- Payment card recognition. Google Pay’s API allows customers to use their device’s camera to capture their card details. This makes paying for your products or services quick and convenient and can lead to fewer abandoned carts, particularly because customers don’t need to have the Google Pay digital wallet for this to work.
API availability | On request |
Developer support |
|
API security features |
|
Transaction fees on cheapest plan with API | ~2% + 0¢ |
Monthly subscription on cheapest plan with API | $9.00 |




Custom Payment Processing Plans With No Hidden Costs
Monthly Fee:
From $69
Transaction Fee:
From 0% + 15¢
Pricing Model:
Multiple options
Multiple options
This payment processor allows you to choose from two or more different pricing models for paying credit card processing fees. Each model will come with its own advantages and disadvantages, so make sure to consider your options carefully before deciding which is right for your business.
Features and Benefits
- Diverse pricing structure. PAYARC’s flat rate pricing is a great fit for smaller businesses that process a lower volume of card payments. You’ll only have to pay a per-transaction rate of 2.49% + 30¢ (in-person) and 2.9% + 30¢ (online). If you process more, you can save with PAYARC’s membership-based plans starting at $69.00/month with fees as low as 0% + 15¢ (in-person & online).
- Well-written documentation. PAYARC provides thorough documentation for its API, and includes detailed implementation for a variety of uses, including subscriptions, disputes, webhook triggers, and payment pages.
- Coupons. PAYARC’s API lets you create custom coupons to offer special sales, run promotions, and attract new customers with first-order discounts.
- 24/7 support. PAYARC has a team of professionals available 24/7 on the phone to answer your questions and solve your issues. Alternatively, you can reach its support via email.
API Availability | On all plans |
Developer Support |
|
API Security Features |
|
Transaction fees on cheapest plan | 2.49% + 30¢ (in-person) |
Monthly fee on cheapest plan | N/A |




Interchange-Plus & Zero Cost Processing Plans Ideal for Restaurants and Retail
Monthly Fee:
$7.95
Transaction Fee:
From 3% + 10¢
Pricing Model:
Multiple options
Multiple options
This payment processor allows you to choose from two or more different pricing models for paying credit card processing fees. Each model will come with its own advantages and disadvantages, so make sure to consider your options carefully before deciding which is right for your business.
Features and Benefits
- Customer profiles. With Authorize.net’s API, you can store customer billing, payment, and shipping details. For about 25¢ per update, you can refresh credit card data, reducing payment interruptions.
- Easy invoicing. Authorize.net allows you to send email invoices using a “click to pay” link, along with reminders for unpaid invoices.
- Automatic recurring billing. Using Authorize.net’s API, you can set up monthly or custom automatic billing monthly. This removes the need to re-enter customer information and ensures you always get paid on time, boosting your cash flow.
- Simple checkout. With Authorize.net’s API, you can add a “Buy Now” button to your website for a frictionless payment experience.
API Availability | On request |
Developer Support |
|
API Security Features |
|
Transaction fees on cheapest plan with API | 3% + 10¢ (credit) |
Monthly fee on cheapest plan with API | $7.95 |




Fast Onboarding & Quick Payouts With Same-Day Funding
Monthly Fee:
From $15
Transaction Fee:
From 1.58% + 19¢
Pricing Model:
Multiple options
Multiple options
This payment processor allows you to choose from two or more different pricing models for paying credit card processing fees. Each model will come with its own advantages and disadvantages, so make sure to consider your options carefully before deciding which is right for your business.
Features and Benefits
- Quick setup. Applying for a Flagship merchant account only takes a few minutes, and you can begin processing in as little as a few hours. Once accepted, you can take your first payments with Authorize.net on the next business day.
- Great security features. In addition to Authorize.net’s built-in security features, Flagship uses tokenization to secure all customer and payment data on its servers. It’s also fully PCI, GDPR, and CCPA compliant.
- Fast funding. Flagship offers same-day funding as an optional add-on, a handy feature for new businesses that need steady cash flow.
- PCI compliance support. Flagship will regularly scan your merchant account to ensure you’re fully PCI compliant.
API availability | On request |
Developer support |
|
API security features |
|
Transaction fees on cheapest plan with API | 1.58% + 19¢ (in person) |
Monthly subscription on cheapest plan with API | $7.95 |




Save Up to 40% on Credit Card Processing Fees
Monthly Fee:
From $99
Transaction Fee:
From 0% + 10¢
Pricing Model:
Subscription
Subscription
With subscription-style pricing, you’ll pay a fixed monthly fee instead of a percentage-based markup on each credit and debit card transaction. While this will considerably reduce your per-transaction fees, you’ll typically still pay a small flat fee on each transaction. This amount is unaffected by the variable interchange fees charged by the different card networks (e.g. Visa, Mastercard), helping to keep your payment processing fees more predictable.
Features and Benefits
- Embeddable payment forms. Some customers will abandon their cart if they’re redirected to the webpage of a third-party gateway when it’s time to pay. Stax.js allows you to embed a payment form into your website to reduce cart abandonment and improve trust with your customers.
- Language agnostic. Stax’s API is designed to work with any language that can interact with REST API, enabling you to use this API with a wide variety of software suites.
- Quick-start guide. Stax has a quick-start API guide that shows you how to set up sandbox and production accounts, how to use Stax.js, and how to generate API keys. While this document is relatively short, it has quick links to other documentation pages so you can quickly find what you need.
- PCI compliance support. Merchants using self-hosted payment APIs usually have to undergo a lengthy assessment. With Stax, you’ll get access to a third-party PCI compliance dashboard that will alert you when your security assessment is due and guide you through the questionnaire.
API availability | Pro and Ultimate plans |
Developer support |
|
API security features |
|
Transaction fees on cheapest plan with API | 0% + 10¢ (in-person) |
Monthly subscription on cheapest plan with API | $99.00 |
6. Helcim: A Free API for Budget-Conscious Businesses




Budget-Friendly Credit Card Processing Ideal for New or Low-Volume Businesses
Monthly Fee:
None
Transaction Fee:
From 0.30% + 8¢
Pricing Model:
Interchange plus
Interchange plus
Interchange-plus pricing involves two fees for each credit or debit card transaction. The first is the interchange fee, a variable amount set by the card network (e.g. Visa, Mastercard). The second is a markup fee charged by the payment processor, typically a percentage of the transaction amount plus a small flat transaction fee. This allows you to see exactly how much of what you pay goes to the card networks and how much to the payment processor.
Features and Benefits
- Built-in security. Helcim’s API uses secure ports, SSL certificates, and encryption keys, and the handful of ciphers it allows all provide a high level of data security. If the API can’t connect to Helcim’s server using a secure pathway, the server will refuse the request.
- Helcim Card Vault. Customers can opt to store cards in their profile, which are tokenized and saved on Helcim’s servers. Helcim’s API can access this data, allowing you to build custom applications that make it as convenient as possible for customers to pay you.
- Helcim Fraud Defender. You can use Helcim’s API to connect to Fraud Defender, which checks specific card transactions for fraudulent activity. Fraud Defender will then give you an analysis of that customer’s history, AVS, and more.
- Hosted payment pages. Helcim’s API allows you to build checkout pages where captured payment data is sent through Helcim’s servers rather than yours. This reduces the risk of a data breach and means you don’t have to worry about making your own server PCI-compliant.
API Availability | On all plans |
Developer support |
|
API security features |
|
Transaction fees on cheapest plan with API | 0.30% + 8¢ (in-person) |
Monthly subscription on cheapest plan with API | N/A |
Other Notable Credit Card Processing APIs
7. Chase Payment Solutions
Chase Payment Solutions provides a variety of proprietary and third-party APIs that cater to small and medium-sized businesses (SMBs) and Software as a Service (SaaS) companies. For SMBs, it provides APIs for the Orbital gateway and virtual terminal, digital wallets, e-commerce solutions, and more. It also has a few WePay developer kits for SaaS companies. With the WePay APIs, you can brand Chase’s payment solutions as your own. While Chase has an extensive suite of APIs, it might not fit every business. It doesn’t cater to high-risk merchants. Some of its APIs also require developer support, which could be expensive for small and growing businesses. However, Chase might be a good choice if you have the necessary resources and deal with complex payment needs.8. CreditCardProcessing.com
CreditCardProcessing.com doesn’t have its own API but offers limited access to the Authorize.net API at a quarter of its regular price. This could be a great option if you can handle everything on your own and have a fair knowledge of how to integrate APIs. This processor offers affordable subscriptions with lower-than-usual transaction fees for high-volume businesses. It’s worth mentioning that CreditCardProcessing.com’s interchange-plus pricing isn’t the best, though. There are also additional fees to access customer service, which is typically free elsewhere. You can likely negotiate a better deal at LMS if you run a small business.Which Is the Best Credit Card Processing API?
If you want to build custom e-commerce features, you’re going to need a well-documented and comprehensive credit card processing API that you can easily integrate with your current e-commerce solutions. Leaders Merchant Services (LMS) is the best choice for most small businesses, including those processing a lower volume of card sales. It offers some of the industry’s lowest interchange-plus pricing and you can negotiate your rates and tailor your plan. While LMS charges a fee for using Authorize.net’s API, you can use Google Pay’s API for free, which is a great way to keep your costs down. If your business is growing and you’re expanding into international markets, I recommend PAYARC. You’ll get free access to PAYARC’s extensive APIs and SDKs, plus API onboarding. For a low fee of $5 per month, you can integrate PAYARC’s proprietary gateway. You can also integrate some of its third-party international gateways. ProMerchant is another great option for businesses that operate both in-person and online. It offers integration with the trusted Authorize.net API, which provides access to additional security features. It also provides a virtual terminal through Authorize.net and Payments Hub at no extra cost. Additionally, you’ll receive free POS hardware to support your in-person operations.Keep scrolling for a quick comparison of the best payment APIs.
Best Feature | Best For | Monthly fee on cheapest plan with API | Transaction fees on cheapest plan with API | ||
Leaders Merchant Services | API solutions through Authorize.net or Google Pay | Budget-conscious businesses that only want to pay for the features they need | $9.00 | ~2% + 0¢ | |
PAYARC | Free API and integrations with third-party payment gateways that support processing in 150+ currencies | Businesses that sell internationally | N/A | 2.49% + 30¢ (in-person) | |
ProMerchant | Integration with the trusted Authorize.net API and a free virtual terminal | Businesses that process all kinds of transactions (in-person, online, MOTO) | $7.95 | 3% + 10¢ (credit) | |
Flagship Merchant Services | Negotiable rates with affordable access to Authorize.net | Businesses that are happy to negotiate for a custom payment solution | $7.95 | 1.58% + 19¢ (in person) | |
Stax | Fully-documented API with built-in security features | Businesses that need secure custom payment solutions for websites and mobile apps | $99.00 | 0% + 10¢ (in-person) | |
Helcim | A proprietary API with over 80 available API actions | Businesses that don’t want to pay an additional monthly fee for a third-party gateway | N/A | 0.30% + 8¢ (in-person) |