The 8 Best Payment APIs For Small Business Transactions
When you're ready to dive into the world of credit card APIs, you'll want to compare and contrast the developer tools provided by payment services providers.
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WRITTEN & RESEARCHED BY
Senior Staff Writer
Last updated onUpdated
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REVIEWED BY
Lead Staff Writer
Advertiser Disclosure: Our unbiased reviews and content are supported in part by affiliate partnerships, and we adhere to strict guidelines to preserve editorial integrity.
If you’ve ever run into the limitations of your payment infrastructure, it may be time to consider using a payment API. With a payment API, developers on your team can create a custom payment processing setup more specifically tailored to your needs. Below, we’ll look at some versatile payment APIs and their use cases with the best credit card processors for small businesses.
Remember, it’s important to evaluate payment APIs not just by their features but also by how much they cost, how secure they are, and how troublesome they may be to use.
Keep on reading to find out more!
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Table of Contents [hide][show]
- What Is A Payment API?
- 8 Best Credit Card & Payment APIs For Developers
- Helcim: Best For Easy Scaling
- Stax by Fattmerchant: Best For eCommerce Businesses
- Stripe Payments: Best For Developer Resources
- Square: Best For New & Seasonal Businesses
- Host Merchant Services: Best For Customer Service
- Authorize.Net: Best Portable Payment Gateway
- Braintree Payment Solutions: Best For PayPal Integration
- GoCardless: Best For Standalone ACH processing
- What To Look For In A Payment Processor API
- Payment Processing Costs & Payment APIs
- How To Choose The Best Payment Gateway API For Your Needs
Table of Contents
- What Is A Payment API?
- 8 Best Credit Card & Payment APIs For Developers
- Best Credit Card & Payment APIs Compared
- Helcim: Best For Easy Scaling
- Helcim
- Helcim Payment API Features
- Helcim Pricing
- Stax by Fattmerchant: Best For eCommerce Businesses
- Stax by Fattmerchant
- Stax Features
- Stax Pricing
- Stripe Payments: Best For Developer Resources
- Stripe Payments
- Stripe Features
- Stripe Pricing
- Square: Best For New & Seasonal Businesses
- Square
- Square Features
- Square Pricing
- Host Merchant Services: Best For Customer Service
- Host Merchant Services
- Host Merchant Services Features
- Host Merchant Services Pricing
- Authorize.Net: Best Portable Payment Gateway
- Authorize.Net
- Authorize.Net Features
- Authorize.Net Pricing
- Braintree Payment Solutions: Best For PayPal Integration
- Braintree Payment Solutions
- Braintree Features
- Braintree Pricing
- GoCardless: Best For Standalone ACH processing
- GoCardless Features
- GoCardless Pricing
- Payment Processing Rating Methodology
- What To Look For In A Payment Processor API
- Payment Processing Costs & Payment APIs
- How To Choose The Best Payment Gateway API For Your Needs
What Is A Payment API?
A payment API, or application programming interface, allows businesses to use infrastructure and functionality belonging to payment processors to build their own custom payment interfaces.
8 Best Credit Card & Payment APIs For Developers
Payment APIs are a feature provided by a payment processing company or payment gateway, so you’ll need to subscribe to the service to access the API. Below, we’ve listed some of the best credit card processing companies and related services that come with excellent payment APIs.
- Helcim: Best For Easy Scaling
- Stax by Fattmerchant: Best For eCommerce Businesses
- Stripe Payments: Best For Developer Resources
- Square: Best For New & Seasonal Businesses
- Host Merchant Services: Best For Customer Service
- Authorize.Net: Best Portable Payment Gateway
- Braintree Payment Solutions: Best For PayPal Integration
- GoCardless: Best For Standalone ACH processing
Best Credit Card & Payment APIs Compared
| Account Type | Languages Supported | |
|---|---|---|
| Helcim | Merchant Account | Node.js, Ruby, PHP, Python |
| Stax by Fattmerchant | Merchant Account | Node.js, Ruby, PHP, Python, Java |
| Stripe Payments | Aggregated Account | Ruby, Python, PHP, Java, Node.js, Go |
| Square | Aggregated Account | PHP, Java, Python, Node.js, Ruby |
| Host Merchant Services | Merchant Account | Java, PHP |
| Authorize.Net | Payment Gateway | PHS, CS, Java Ruby, Python, Node.js |
| Braintree Payment Solutions | Merchant Account | Java, Ruby, Node.js, PHP, Python |
| GoCardless | ACH Payments | Java, Python, Ruby, PHP |
Helcim: Best For Easy Scaling
Pros
- Transparent interchange-plus pricing
- No long-term contracts
- Good developer resources
Cons
- Not suitable for high-risk industries
- May not be cost-effective for very low volume businesses
Why Helcim Is The Payment API For Growing Businesses
Helcim is one of our favorite payment processors, and it's not too hard to see why. Helcim offers transparent interchange-plus processing, no long-term contracts, and extensive fee disclosures. Not only that, but it also scales well with business growth and can handle international payments.
Compared to some of the other services on this list, Helcim's developer tools fall somewhere in the middle of the pack. They're more than serviceable, however, with a folder-like layout and ample screenshots. The Helcim API is a RESTful API and can be used with any language that can make an API call. In an interesting desktop layout choice, code samples live just offscreen and can be slid on or off the center of your screen with a click.
Ideal For...
- Business that may grow quickly
Stax by Fattmerchant: Best For eCommerce Businesses
Pros
- Good for high-volume sellers
- Impressive feature set
- Upfront pricing and fees
Cons
- Expensive for low-volume sellers
- Not available for high-risk businesses
Why Stax Is The Best Payment API For eCommerce Businesses
Stax is best suited for larger businesses with a high number of sales, and it also caters its services to businesses that do the bulk of their selling online. Stax has a wide variety of integrations with shopping carts. It also has its own website builder.
Stax is also an excellent choice for businesses that sell software or online services like subscriptions. Stax has upfront pricing that takes the guesswork out of processing fees but its rates may be a bit high for smaller volume sellers. Its strong feature set also makes Stax a very viable option for in-person sellers as well.
Ideal For...
- Businesses that primarily sell online
Get Started With Stax by Fattmerchant
Stripe Payments: Best For Developer Resources
Pros
- Predictable flat-rate pricing
- Excellent developer resources
- Excellent support for international currencies & payment methods
Cons
- Account stability issues
- Not suitable for high-risk industries
Why Stripe Is The Best Choice For Businesses That Want Access To Excellent Developer Resources
When it comes to developer support--always important where payment gateways are concerned--Stripe is pretty close to the gold standard for payment processors. The online documentation is exhaustive, easy to parse, and full of readily accessible code snippets in each of the server-side languages it supports (Ruby, Python, Java, PHP, Node.js, Go, and .NET). Stripe also has links to boilerplate projects you can clone and build upon.
Ideal For...
- Businesses with skilled developers
Get Started With Stripe Payments
Square: Best For New & Seasonal Businesses
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Pros
- Predictable flat-rate pricing
- Enables omnichannel selling
- Excellent public documentation
Cons
- Account stability issues
- Not suitable for most high-risk industries
Why Square Is The Best Payment API For New & Seasonal Businesses
Square is more or less synonymous with "quantity of features." You'll get a lot of functionality out of this processor, and all without paying a monthly fee.
As you may expect of an ecosystem as large and complex as Square's, several different Square APIs allow developers to access different parts of the processor's infrastructure. Thankfully, Square provides an API Explorer to help you find what you need. Square provides ample documentation on its developer site, custom SDKs, and a sandbox to make development easier.
Ideal For...
- Businesses just starting out
Host Merchant Services: Best For Customer Service
Pros
- Transparent interchange-plus pricing
- No long-term contracts
- No monthly minimums
Cons
- Can be expensive for low volume merchants
- Monthly fees can add up
Why Host Merchant Services Is The Best Choice For Businesses Looking For Strong Customer Service
Host Merchant Services gets high marks for its customer service, which also extends to its developer support and easy-to-use API. Popular gateways like Authorize.Net are easily added to the service. Additionally, Host Merchant Services offers interchange-plus pricing to all of its clients, with guaranteed rates for the life of the account, making it a reliable, cost-effective processor for mature businesses.
HMS does not charge any early termination fees or have long-term contracts. In fact, HMS will even pay up to $250 in early termination fees for referred clients ($500 in the client processes over $50,000/month) if they leave their current processor for HMS.
Ideal For...
- Businesses needing extensive support
Get Started With Host Merchant Services
Authorize.Net: Best Portable Payment Gateway
Pros
- Versatile standalone payment gateway
- Live console available in documentation
- Excellent developer resources
Cons
- Expensive if not included in bundle
- Requires a payment processor as well
Why Authorize.Net Is The Best Portable Payment Gateway
As a dedicated payment gateway, Authorize.Net can connect your online store to your payment processor, provide support for multiple currencies, add security features, provide recurring billing services, and enable echeck processing.
In terms of developer resources, Authorize.Net may be one of Stripe's closest rivals. There's a ton of documentation, including API references, developer guides, and a collection of PCI-compliant tools called the Accept Suite. Most of it is publicly viewable, so you can check it out before you commit to anything. Much of the documentation contains an API live console, so you can test out snippets of code without leaving the resources.
Most importantly, Authorize.Net can be paired with a huge number of merchant services.
Ideal For...
- Businesses seeking processing flexibility
Get Started With Authorize.Net
Braintree Payment Solutions: Best For PayPal Integration
Pros
- Predictable flat-rate pricing
- Excellent developer resources
- Integrates with PayPal ecosystem
- Full merchant account with payment platform perks
Cons
- Not suitable for high-risk industries
- Transactions rates are expensive relative to competitors
- Standalone gateway option is costly
Why Braintree Is The Best For PayPal Integrations
At first glance, Braintree's profile is very similar to Stripe's -- they both combine payment services and gateway functionality with an eye toward international eCommerce.
There are two important differences at this level, however. The first is that Braintree provides a merchant account rather than third-party processing, so you're getting better account stability, but you should expect to have to jump through some additional hoops and wait times to set it up. And unlike Stripe, it is possible just to use Braintree as a payment gateway if you already have a merchant account. I wouldn't recommend this, though, as using Braintree's gateway à la carte is more expensive than most other independent gateways.
For developers, Braintree provides sandbox accounts to explore the service's functionality. The online documentation is extensive if not quite as slickly presented as Stripe's -- you have to toggle between programming languages at the top of each page rather than each code snippet, for example. The payment API reference section for developers is well laid out, however, making it easy to look up the methods you'll need when you need them.
Ideal For...
- Businesses already selling with PayPal
Get Started With Braintree Payment Solutions
GoCardless: Best For Standalone ACH processing
GoCardless |
|---|
Pros
- Cost-effective ACH solution
- International bank-to-bank transfers
- Low transaction fees
Cons
- No credit/debit card processing support
- API access locked behind monthly fee
Why GoCardless Is The Best Payment API For Standalone ACH Processing
The ability to process ACH payments provides merchants with a strong alternative to credit card payments, especially where recurring and subscription payments are concerned. While some payment processing platforms include ACH out of the box, it's a bit more uncommon to find affordable standalone ACH services. Businesses looking for such a service should consider GoCardless, a simple and cost-effective way to get ACH payments with no added bloat.
As a bonus, you'll also get international payment service through Wise.
Ideal For...
- International sellers
Payment Processing Rating Methodology
Merchant Maverick has been researching the payment processing industry since 2009. Our writers have reviewed hundreds of credit card processors, merchant account services, and mobile payment apps, evaluating each provider carefully on several different metrics.
When comparing different payment processing companies and applications to one another, we consider numerous data points. Our experts start by comparing credit card processing rates, the presence of additional fees, contract length, sales practices, and the presence or absence of additional features and services, like point of sale software. Each provider is judged on its own merits and how well it stacks up to industry standards; then it is weighed against the other providers on the list.
We spend an average of 10-15 hours researching and updating each one of our lists, making sure every company or application included meets our internal standards for quality and reputation. Any list of recommended payment processors on our site might contain a mix of standard merchant accounts, third-party payment processors, mobile payment devices, and high-risk payment processors, depending on what our expert feels is the best fit for certain scenarios or business types.
For additional details about Merchant Maverick’s review and rating processes, please refer to any or all of the following methodology pages:
- Credit card processor rating criteria
- High-risk merchant account rating criteria
- Credit card reader & mobile payment device rating criteria
15
Years reviewing payment processors
100+
Providers evaluated
25
Attributes and features assessed per vendor
40+
Years combined experience
What To Look For In A Payment Processor API
What makes a good payment processor API? There are a few factors I’d keep in mind when you’re looking for a developer-friendly payment processor.
Payment Processing Costs & Payment APIs
While some APIs are free to use, that’s not the case when it comes to payment processors. If you’re using a payment API, that usually means you’re going to have to be a customer of that payment processor.
That said, costs will vary greatly depending on the payment processor. Some processors, such as Stripe, will give you access to their API as part of the basic service. Since it’s a month-to-month service with no monthly fee, you’ll only pay the transaction costs, plus any premium features you sign up for. With other payment processors, the API may only be available if you are buying a premium plan.
Costs for payment API usage may include:
- Transaction Fees: This is the amount of money that will be deducted from each of your sales. This amount will vary by payment method. While it’s usually the same regardless of whether you’re using an API or not, some APIs may allow you to use surcharging to pass on some costs to your customers.
- Monthly Fees: These are membership fees you pay to keep your account going. Not all processors charge monthly fees. Some will only charge monthly fees for premium plans.
- Gateway Fees: APIs are frequent functions of payment gateways. Some payment processors have integrated payment gateway APIs, while others use third-party gateways. Be aware of any additional monthly or transaction fees you have to pay to use a payment gateway.
How To Choose The Best Payment Gateway API For Your Needs
Now that we’ve covered some of the heavier hitters in the payment processing API department, you should be able to dig in a little further and match their capabilities to your needs. Even the best credit card processing companies may not offer the API access you’re looking for.
Take stock of your developers’ strengths and encourage them to poke around publicly available documentation; they can give you a good idea of whether the platform can be hammered into the small business credit card processing tool you need.
If you’re going to be tinkering with a payment API, it might be a good time to brush up on PCI compliance and security features, such as credit card tokenization and fraud detection. If you’re looking to customize your payment workflow, you may also want to read up on everything you need to know about alternative payment methods.
Chris Motola
Senior Staff Writer at Merchant Maverick
Chris has been writing about small business topics since 2003. In 2015, he joined Merchant Maverick, where he writes about business financing, payment processing, and demographic trends in entrepreneurship. Chris has been featured in Fox Business, ABC News, Yahoo Finance, GoBankingRates, Newsweek, BizJournals, and other publications. He has a Bachelor’s of Arts in English Writing Arts from SUNY Oswego, and a Masters of Science in Interactive Media from the University of Central Florida. He currently resides in the Hudson Valley region of New York.
View Chris Motola's professional experience on LinkedIn.
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