The 7 Best Payment Gateway & Credit Card APIs For Developers

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.

Stripe is a pay-as-you-go service. Most of the costs of using Stripe are built into transaction fees rather than as recurring monthly fees. The one exception is:

• Premium support: $1,800/month

How does Stripe work? Well, Stripe combines the functionality of a third-party payment processor and a gateway into a single package. This will be convenient for many businesses, provided they don’t already have a merchant account that they want to hold onto, as Stripe doesn’t let you use its gateway à la carte; it’s all or nothing. Stripe’s API is deep and versatile, especially when it comes to eCommerce. Features include:

• Credit & debit cards
• ACH
• Google Pay
• Apple Pay
• Invoices
• International currency support
• International payment method support
• Account routing by currency

• Stripe Reader M2: $59
• BBPOS
  • Chipper 2xBT: $59
  • Wise POS E: $249
  • Wise 3: $79 (Canadian)
• Verifone P400: $299

• Card-present: 2.7% + $0.05
• Card-not-present: 2.9% + $0.30
• ACH: 0.8% (max. $5)

Stripe does not have long-term contracts or early termination fees.

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.

Square is a pay-as-you-go service that is funded almost entirely by transaction fees (see below). Square does offer a new of subscription-based services, however.

• Square Appointments: $0 – $69/month
• Square For Retail: $0 – $60/month
• Square For Restaurants: $0 – $60/month
• Square Invoices: $0 – $20/month

Square’s payment gateway allows users to access aspects of its “full-stack” payment service. Square has built up an enormous platform that provides a variety of tools to both eCommerce and brick-and-mortar businesses — including marketing, loans, loyalty programs, productivity, inventory, etc. — on top of processing card transactions. API features include support for:

• Credit & debit cards
• ACH
• Google Pay
• Apple Pay
• Payouts
• Invoices
• Inventory control
• Customer management
• Loyalty programs
• Booking
• Team management
• Proprietary gateway

• Basic Magstripe Card Reader: $10 (first is free)
• Square Contactless & Chip Reader: $49
• Square Stand With Contactless & Chip Reader: $169
• Square Register: $799

• Card-present: 2.6% + $0.10
• Card-not-present: 2.9% + $0.30
• Keyed-in: 3.5% + $0.15
• ACH: 1% (min. $1)

As we mentioned above, Square is a month-to-month service that can be cancelled without penalty. Just be aware that if you’re testing out a free trial of a Square subscription-based service, you’ll need to wait for your trial to conclude to cancel.

Host Merchant Services gets high marks for its customer service, which also extends to its developer support and easy-to-use API. 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.

Major recurring fees for Host Merchant Services include:

• Account fee: $14.99/month
• 1099 Reporting fee: $24/year
• Gateway fee: $5 – $10/month
• PCI compliance fee: $49/year
• Batch fee: $0.20/batch

Host Merchant Services runs a bit leaner than the big third-party processing platforms but still provides a lot of value for the price. Features include:

• Credit & debit cards
• ACH
• Google Pay
• Apple Pay
• Shopping cart integration
• Web hosting
• Featured payment gateways:
  • Transaction Express
  • Authorize.Net
  • NMI Gateway

• PAX
  • A920
  • A80
• Verifone
  • VX520
• Ingenico
  • iCT250
  • iCT220
  • iWL250
  • iWL255
• Dejavoo
  • Z8
  • Z9
• Vital
  • C3
  • C4
• SwipeSimple Mobile EMV Processing
• Rambler 3.0 Mobile Swiper

Note, prices below are for transaction volumes above $10,000 per month. Rates are higher for lower-volume businesses.

• Retail: Interchange + 0.25% + $0.10
• Restaurant: Interchange + 0.2% + $0.09
• eCommerce: Interchange + 0.35% + $0.25

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.

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.

Helcim pulls off an unusual hat trick by offering interchange-plus pricing with no monthly fees.

While it may not be as well-known a name as Square or Stripe, Helcim is an all-around excellent payment processor with an API that covers most of the bases.

• Credit & debit cards
• ACH
• Google Pay
• Apple Pay
• Invoices
• Inventory management
• Support for Canadian payment methods
• Customer management
• Card vault

• Helcim Card Reader w/countertop stand: $109
• ZJ-5809 Lightweight Thermal Printer: $79

• Note: rates posted below are for businesses processing less than $25,000/month. Rates will be lower for businesses processing more than $25,000/month
  • Card-Present: Interchange + 0.3% + $0.08
  • Card-Not-Present: Interchange + 0.5% + $0.25

Helcim does not have long-term contracts or early termination fees.

As a 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.

Note, Authorize.Net pricing varies depending on the services it’s bundled with. Below is the cost of the gateway-only option, which is in addition to any fees charged by your payment processor.

• Monthly fee: $25

Most of the other services on this list have been payment processors. Authorize.Net, however, is a standalone payment gateway offered by Visa. You’ll often see it bundled with other services (which is how we’d recommend you use it). Remember, you’ll still need a merchant account/payment processor to process credit cards with Authorize.Net.

• Credit & debit cards
• ACH
• Google Pay
• Apple Pay
• Customer information management
• Syncs with Quickbooks
• Advanced fraud detection
• International currency support

Available hardware will vary by the payment processor you choose.

Note: this transaction fee applies only to Authorize.Net’s standalone pricing. Transaction rates will vary depending on how Authorize.Net is bundled.

• Transaction fee: $0.10

Authorize.Net does not have any long-term contracts or early termination fees. However, be aware that your payment processor may have long-term contracts even if Authorize.Net does not.

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.

Braintree is funded through transaction fees, so there are no recurring fees for the basic service. If you use the gateway as a standalone, which we don’t recommend, these are the monthly fees:

• Gateway fee: $49/month
• Additional merchant accounts (beyond the first): $10/month

Braintree is part of the PayPal payment services family, along with sister services PayPal and Venmo. It does, however, function semi-autonomously from the other companies and has a slightly different focus.

• Credit and debit card processing
• ACH
• PayPal
• Venmo
• Apple Pay
• Google Pay
• Samsung Pay
• Currency conversion
• Gateway can be used standalone
• Support for international payment methods
• Excellent developer tools
• Access to PayPal ecosystem

• Credit & debit cards: 2.59% + $0.49
• ACH: 0.75% (max. $5)
• Venmo: 3.49% + $0.49
• Gateway fee (standalone option only): $0.10

Braintree’s plans do not have any long-term contracts or early termination fees.

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.

GoCardless offers several plans.

• Pay-as-you-go: No monthly fee
• Plus package: $25/month
• Pro package: $75/month

GoCardless’s features are oriented around ACH payment customization and security.

• ACH
• International transfers (Wise)
• Subscription/recurring payments
• Online customer sign-up
• Bank verification
• Reporting tools
• Branded payments(Plus and Pro)
• Payment page customization (Plus and Pro)
• API access (Pro)

• ACH transaction fee: 1% + $0.25 (max $2.50)
  • Additional fee for transactions over $1,000: 0.3%
• International transaction fee: 2% + $0.25 (includes currency conversion)

GoCardless’s plans do not have any long-term contracts or early termination fees.