Here are secure payment-gateway options for e‑commerce, grouped by typical merchant needs, with the gateway’s main security features, pros/cons, and quick guidance on when to choose each.

Summary (quick picks)

• Developer / custom checkout: Stripe or Checkout.com. (stripe.com, checkout.com)
• Small business / simple setup: PayPal (or Braintree) or Square. (braintreepayments.com, squareup.com)
• Global enterprise / high-volume: Adyen or Checkout.com (or Worldpay/FIS). (docs.adyen.com, checkout.com)
• High fraud-risk or complex rule needs: Authorize.Net (AFDS) or a gateway with advanced risk tools. (authorize.net)

Recommended gateways (details)

1. Stripe — developer-first, strong security & PCI support

• Security highlights: PCI Level 1 service provider, tokenization, TLS encryption, optional hosted Checkout/Elements to reduce PCI scope, fraud tools (Radar) and 3D Secure support.
• Why choose: Flexible APIs for custom flows, strong docs and built-in compliance help for merchants. (stripe.com)

2. PayPal / Braintree — broad reach, tokenization, proven compliance

• Security highlights: Level 1 PCI DSS, large token vault (network tokens), hosted checkout options to minimize merchant PCI scope, 3D Secure support via Braintree.
• Why choose: Easy buyer trust (PayPal brand), good for international wallets and one-click flows; Braintree gives more dev control. (newsroom.paypal-corp.com, developer.paypal.com)

3. Adyen — enterprise-grade, global authentication & risk

• Security highlights: 3D Secure 2 support, strong risk/AI fraud tools, tokenization and global payment method coverage, built-in SCA/PSD2 support where required.
• Why choose: Best for large merchants that need global coverage, fine-grained risk controls, and a single platform for online + in‑store. (docs.adyen.com)

4. Checkout.com — performance + modern authentication

• Security highlights: 3D Secure 2.x, network-token support, token vault, centralized authentication options and strong uptime/resiliency focus.
• Why choose: Good for merchants needing fast authentication, custom flows, and multi-acquirer setups. (checkout.com)

5. Authorize.Net — strong fraud-filtering & merchant-account flexibility

• Security highlights: PCI Level 1, tokenization, Advanced Fraud Detection Suite (many customizable filters: velocity, AVS/CCV handling, IP velocity, etc.).
• Why choose: Good if you want powerful, rules-based fraud filters and the ability to use your own merchant account. (authorize.net, developer.authorize.net)

6. Square — simple, end‑to‑end encryption for SMBs and omnichannel

• Security highlights: End-to-end encryption in readers, tokenization in Square’s vault, PCI compliance handled for merchants, SOC/ISO attestations.
• Why choose: Best for U.S. small/brick-and-mortar merchants who want easy online + in‑person integration and lower PCI burden. (squareup.com)

7. Regional / specialty gateways (pick by market)

• Examples: Mollie (EU), Razorpay (India), Worldpay/FIS (global/enterprise). These specialize in local payment methods, regulatory compliance (SCA/PSD2 in EU, UPI/IMPS in India), and local acquiring. Choose by target markets. (thefinrate.com, ecommerceblogss.com)

Key security features to look for (and why they matter)

• PCI DSS Level 1 (or provider reduces your PCI scope): reduces risk and audit burden. Enable hosted checkout or tokenization to minimize your SAQ obligations. (stripe.com)
• Tokenization / network tokens: replaces PANs with tokens so card data breaches are less damaging and stored credentials remain current. (checkout.com, newsroom.paypal-corp.com)
• 3D Secure 2 / SCA support: required or strongly recommended in many regions (EEA) for liability shift and regulatory compliance; reduces fraud liability. (docs.adyen.com, checkout.com)
• Strong fraud tools (ML risk scoring, velocity rules, device fingerprinting): lets you balance approval rates vs. fraud. (authorize.net, checkout.com)
• End-to-end encryption (TLS + on-device encryption for POS): protects data in transit and at the point of capture. (squareup.com)

Practical security/hardening steps to implement (short checklist)

• Use a hosted checkout or client-side tokenization so raw PANs never touch your servers (reduces PCI scope). (stripe.com)
• Enable 3D Secure 2 (challenge or frictionless flows) where applicable to shift liability and comply with SCA. (docs.adyen.com, checkout.com)
• Store only tokens, not card details; rotate keys and use network tokens where supported. (checkout.com, newsroom.paypal-corp.com)
• Deploy gateway fraud tools and add your own business rules (velocity, geo-blocking, AVS/CCV). Monitor and tune them regularly. (authorize.net, support.authorize.net)
• Use strong TLS, keep software up to date, and enforce MFA for dashboard access; run regular vulnerability scans/pen tests. (squareup.com, braintreepayments.com)

Fees & integration notes (high-level)

• Fees vary by provider, country, volume and payment method (interchange + mark-up or flat % + fixed charge). Some gateways (Stripe, Adyen, Checkout.com) are developer-centric; others (PayPal, Square) are faster to set up with less engineering. Check current rates for your region before deciding. (techradar.com)

Quick decision guide (which to pick)

• You want full custom checkout + global payments: Stripe or Checkout.com. (stripe.com, checkout.com)
• You need fast setup, high buyer trust, and wallet options: PayPal / Braintree or Square. (braintreepayments.com, squareup.com)
• You’re enterprise, global, or need advanced routing and risk controls: Adyen or Checkout.com (or Worldpay). (docs.adyen.com, checkout.com)
• You have unusually high fraud exposure or need complex rule-based blocking: Authorize.Net with AFDS or additional fraud platforms. (authorize.net)

Sources / further reading (selected official docs & up‑to‑date reviews)

• Stripe — PCI compliance & integration guidance. (stripe.com)
• Adyen — 3D Secure 2 docs and Authentication Engine. (docs.adyen.com)
• Checkout.com — 3DS, network tokens, authentication. (checkout.com)
• Braintree / PayPal — tokenization, PCI, 3DS support. (braintreepayments.com, developer.paypal.com)
• Authorize.Net — Advanced Fraud Detection Suite (AFDS). (authorize.net, support.authorize.net)
• Square — encryption, PCI handling for merchants. (squareup.com)
• Recent industry roundups (comparisons and fee notes). (techradar.com, techrepublic.com)

If you want, I can:

• map these choices to your platform (Shopify/WooCommerce/Magento/custom) and transaction volume and produce a 1–2 page recommended setup (gateway + security settings + estimated fees), or
• provide code snippets for a specific gateway (e.g., Stripe Checkout vs Elements, Braintree Hosted Fields).

(If you want either, tell me platform and monthly volume and I’ll tailor the recommendation.)