apio

Use cases · Online Card Payment APIs

Best Interchange++ Payment Processors

Acquirers offering transparent interchange-plus pricing instead of blended flat rates, for merchants optimizing cost at scale.

Required capability: Interchange++ pricing.

Our pick: PayPal Payments

PayPal Payments is a REST API for accepting payments across 200+ markets, 130+ currencies, and 30+ payment methods, covering ecommerce checkout, subscriptions, invoicing, marketplace payouts, and in-person payments. Pricing is per-transaction: standard card rates start at 2.89% + $0.29 for advanced card processing, with an interchange-plus option for eligible merchants and an additional 1.50% fee on cross-border transactions. The API supports OAuth2, webhooks, idempotency, a sandbox, and SDKs for six languages, and holds SOC 2 Type 2, ISO 27001, and PCI DSS Level 1 certifications.

Best for: Regulated or enterprise workloads - compliance attestations and an enterprise plan; AI agents and automation - an agent-ready surface (MCP / llms.txt); Teams needing broad API coverage out of the box.

Avoid if: You want to try it free before paying

PayPal Payments profile →

Best for…

Best overall
PayPal Payments - our default pick: strongest across pricing, trust and breadth
Best for enterprise
PayPal Payments - for regulated or large teams: SOC 2 Type II, enterprise plan
Cheapest to start
Helcim - from $0.08 transaction + percent to start; compare on your real usage, not the entry price
Best for agents
PayPal Payments - easiest to wire up programmatically: MCP server + llms.txt
Broadest surface
PayPal Payments - 36 documented actions; breadth isn't quality, but it's the most to build on

Ranked (5)

  • #1 PayPal Payments

    68 / 100
    • Best overall
    • Best for enterprise
    • Best for agents
    • Broadest surface

    PayPal Payments is a REST API for accepting payments across 200+ markets, 130+ currencies, and 30+ payment methods, covering ecommerce checkout, subscriptions, invoicing, marketplace payouts, and in-person payments. Pricing is per-transaction: standard card rates start at 2.89% + $0.29 for advanced card processing, with an interchange-plus option for eligible merchants and an additional 1.50% fee on cross-border transactions. The API supports OAuth2, webhooks, idempotency, a sandbox, and SDKs for six languages, and holds SOC 2 Type 2, ISO 27001, and PCI DSS Level 1 certifications.

    PricingHybrid · from $0.29 transaction + percent · free tier ✗
    TrustSOC 2 Type II · GDPR · ISO 27001 · PCI DSS
    Does
    • Hosted checkout
    • In-person / POS
    • Interchange++ pricing
    • Local payment methods
    • Recurring payments
    • Marketplace payouts
    • Built-in fraud tools
    Used byTicketmaster, Grubhub, Southwest Airlines, HelloFresh
    Avoid ifYou want to try it free before paying

    PayPal Payments profile →

  • #2 Authorize.net

    53 / 100

    Authorize.net is a payment gateway, operated by Visa subsidiary CyberSource, that handles ecommerce checkout, recurring billing, in-person card payments, virtual terminal orders, and mobile POS for merchants in the United States, Canada, Australia, and New Zealand. Pricing is hybrid: a per-transaction fee starting at $0.10 with a $25 monthly minimum, and an All-in-One plan that bundles a merchant account for businesses without one. The REST API supports six major languages, webhooks, tokenization, and Apple Pay and Google Pay, with a sandbox available for testing. PCI DSS compliance is confirmed; SOC 2 is not available, and a SOC 1 report can be requested by account owners only.

    PricingHybrid · from $0.10 transaction · free tier ✗
    TrustGDPR · PCI DSS
    Does
    • Hosted checkout
    • In-person / POS
    • Interchange++ pricing
    • Recurring payments
    • Built-in fraud tools
    Avoid ifYou want to try it free before paying

    Authorize.net profile →

  • #3 Mollie

    54 / 100

    Mollie is a European payments platform offering online and in-person payment processing for businesses of all sizes across 30+ EEA markets, covering ecommerce checkout, subscriptions, marketplaces, payouts, and payment links. Pricing is transaction-based (flat fee plus percentage) with published rates and self-serve signup; volume IC++ pricing is available for merchants processing over 100,000 euros per month via sales. The REST API supports OAuth2, idempotency, webhooks, and SDKs for seven languages, and Mollie is PCI DSS Level 1 certified and GDPR compliant.

    PricingUsage · free tier ✗
    TrustGDPR · PCI DSS
    Does
    • Hosted checkout
    • In-person / POS
    • Interchange++ pricing
    • Local payment methods
    • Recurring payments
    • Marketplace payouts
    • Built-in fraud tools
    Used byRosefield, Lounge Underwear, Maisons du Monde, Veloretti
    Avoid ifYou want to try it free before paying

    Mollie profile →

  • #4 Helcim

    50 / 100
    • Cheapest to start

    Helcim is a payment processing platform serving US and Canadian businesses with interchange-plus pricing, no monthly fees, and support for in-person, online, recurring, ACH, and virtual terminal transactions. Pricing is usage-based starting at $0.08 per transaction, with self-serve signup and no sales call required, though merchants processing over $5 million per month move to custom pricing. The REST API supports tokenization, hosted checkout, webhooks, and idempotency, with a sandbox available for testing. Helcim is PCI DSS Level 1 certified and has been operating since 2006.

    PricingUsage · from $0.08 transaction + percent · free tier ✗
    TrustPCI DSS
    Does
    • Hosted checkout
    • In-person / POS
    • Interchange++ pricing
    • Recurring payments
    Used byPatientSERV, Swim Spas and Spas.com Inc., Denver Dads Inc., PCI Communications Inc.
    Avoid ifYou want to try it free before paying

    Helcim profile →

  • #5 Rapyd

    41 / 100

    Rapyd is a fintech platform that lets businesses accept payments, send payouts, and issue cards across 190+ countries through a single REST API, serving use cases from ecommerce checkout and subscription billing to marketplace disbursements and iGaming. Pricing is transaction-based with a percentage component, but rates are not published and require a sales conversation. The API supports HMAC and API key authentication, webhooks, idempotency, and a sandbox environment, with SDKs for Python and TypeScript. Rapyd holds SOC 2 Type II, PCI DSS Level 1, and GDPR certifications, and direct Visa/Mastercard acquiring licenses in the UK, EU, LATAM, Hong Kong, Israel, and Singapore.

    PricingSales-led · free tier ✗
    TrustSOC 2 Type II · GDPR · PCI DSS
    Does
    • Hosted checkout
    • Interchange++ pricing
    • Local payment methods
    • Recurring payments
    • Marketplace payouts
    • Built-in fraud tools
    Used byLittlepay, Spreedly, Paybyrd, Segpay
    Avoid ifYou need transparent pricing up front

    Rapyd profile →

Scope: only APIs with the required capability, picked from published, cited data. The score is one input, not the verdict, and we lead with each one’s trade-off. No reviews yet, no paid placement. See the full Online Card Payment APIs directory.