Card networks
Integrations with Visa, Mastercard, American Express and other card scheme networks provide the routing rails that let a payment platform accept and process card transactions globally. Each network carries its own certification, mandate and compliance requirements that a platform must satisfy before it can route live transactions, which is where Pay Engineers' Authorizations & Compliance service typically gets involved.
Advantages
Global reach across virtually every consumer market and currency; well-established, standardized protocols such as ISO 8583 and increasingly ISO 20022 that most acquiring infrastructure already supports; strong fraud liability shift frameworks like 3-D Secure that reduce merchant risk when used correctly.
Limitations
Significant scheme compliance and certification overhead, including recurring mandate changes that require engineering work to stay compliant; interchange and scheme fees add cost that must be modeled into pricing; certification timelines are controlled by the network, not the integrating platform.
Use cases
Card acquiring and issuing platforms; e-commerce and in-person checkout integrations; cross-border card-present and card-not-present payment flows.
KYC / KYB providers
Know Your Customer and Know Your Business verification providers automate identity and corporate due diligence during onboarding, checking submitted documents and data against government registries, sanctions lists and fraud databases. Outsourcing this to a specialized provider is almost always faster and more defensible to regulators than building verification logic in-house.
Advantages
Speeds up regulatory onboarding significantly compared to manual review processes; access to authoritative government and registry data that would be impractical to source independently; built-in audit trails that satisfy regulator expectations for due diligence evidence; regularly updated as regulatory requirements change.
Limitations
Per-check costs add up at high onboarding volume and need to be modeled into unit economics; verification quality and coverage varies by provider and by country or region, so multi-market platforms may need more than one provider; false negatives and positives still require a human review fallback path.
Use cases
Merchant and business onboarding for KYB; consumer wallet and account onboarding for KYC; periodic re-verification for ongoing compliance.
AML services
Anti-money laundering services screen transactions and customer profiles against sanctions lists, politically exposed person databases and suspicious activity patterns, generating alerts that compliance teams must investigate and, where required, report to regulators. This is a regulatory requirement in virtually every jurisdiction a payment platform can operate in, not an optional risk-management nicety.
Advantages
Automates compliance work that would be practically impossible to do manually at scale, covering sanctions and PEP screening across large transaction volumes; provides an auditable trail of screening decisions for regulators; continuously updated watchlists reduce the risk of missing newly sanctioned entities.
Limitations
Alert volume and false-positive rates require a properly staffed compliance team to investigate, or the tooling's value is undermined; tuning detection rules to your specific risk profile takes ongoing effort; underlying data quality such as name matching and transliteration varies across regions and providers.
Use cases
Transaction monitoring for suspicious activity; sanctions and PEP screening during onboarding and ongoing relationships; regulatory reporting evidence generation.
Anti-fraud engines
Real-time fraud scoring engines evaluate transactions against behavioral, device and network signals to flag or block likely fraudulent activity before it completes, typically within the time budget of a single checkout request. Getting the balance right between blocking fraud and not frustrating legitimate customers is an ongoing tuning exercise, not a one-time integration.
Advantages
Meaningfully reduces fraud losses and chargebacks when properly tuned, directly protecting margin; real-time scoring fits within typical checkout latency budgets; machine-learning-based engines improve over time as they see more transaction data; often bundled with liability shift guarantees from the provider.
Limitations
Requires ongoing tuning to balance fraud capture against false declines of legitimate customers, which directly affects conversion; scoring models need a meaningful volume of historical transaction data to perform well, which is a challenge for new platforms; adds a dependency and latency budget to the checkout critical path.
Use cases
Card-not-present e-commerce checkout flows; account takeover detection on login and payment; marketplace and platform payment flows with elevated fraud exposure.
Identity verification
Identity verification providers combine document authentication with biometric checks such as selfie matching and liveness detection to confirm that the person completing onboarding is who they claim to be and is physically present during the check. This is typically required for higher-risk onboarding flows where KYC document checks alone are not considered sufficient assurance.
Advantages
Provides strong assurance against synthetic identity and impersonation fraud when combined with liveness detection; automates a process that would otherwise require in-person or manual video verification; scales well for consumer onboarding at volume; integrates well alongside standard KYC document checks.
Limitations
Adds friction to the onboarding flow that can measurably affect conversion if over-applied to low-risk segments; accuracy varies across document types, countries and, in some cases, demographic groups, requiring careful provider evaluation; requires clear privacy disclosures and data handling agreements given the biometric data involved.
Use cases
High-risk consumer onboarding flows; step-up verification triggered by risk scoring; regulatory-mandated identity assurance for specific licence types.
SMS gateways
SMS gateways deliver one-time passcodes for two-factor authentication and transactional alerts for payment events, reaching customers on virtually any mobile phone without requiring an app installation. Global coverage and delivery reliability vary significantly by route and provider, which matters a great deal for time-sensitive codes used in authentication flows.
Advantages
Reaches essentially any mobile phone globally without requiring a smartphone app; well understood by end users as a channel for security codes and alerts; multiple provider options allow failover and cost optimization; fast delivery for most routes when properly configured.
Limitations
Delivery reliability and latency vary meaningfully by country and carrier route, which matters for time-sensitive OTP flows; SMS is vulnerable to SIM-swap style social engineering attacks, so it should not be a platform's only authentication factor for high-value actions; costs scale directly with message volume and international routes can be significantly more expensive.
Use cases
One-time passcodes for two-factor authentication; real-time payment alerts and confirmations; account security notifications.
Email services
Transactional email services deliver receipts, statements, security alerts and account notifications reliably, with the deliverability infrastructure, such as SPF, DKIM, DMARC and dedicated IP reputation management, that a payment platform needs to avoid ending up in spam folders for messages customers actually need to see.
Advantages
Reliable, well-understood channel for receipts, statements and non-urgent notifications; dedicated transactional email providers offer strong deliverability tooling and analytics; supports rich formatting for statements and detailed transaction summaries that SMS cannot; generally lower cost per message than SMS.
Limitations
Deliverability requires ongoing domain and sender reputation management including SPF, DKIM and DMARC configuration; not suitable as the sole channel for time-sensitive security codes given typical delivery latency and spam-filtering variability; template and rendering differences across email clients require testing.
Use cases
Transaction receipts and monthly statements; account security and password-reset notifications; marketing-adjacent lifecycle communications with appropriate consent.
Geolocation
Geolocation services derive a customer's approximate physical location from IP address, device signals or carrier data, providing an important input to fraud scoring and regulatory geo-restriction enforcement. It is rarely used as a standalone decision; location signals combined with other fraud indicators are far more reliable than location alone.
Advantages
Provides a useful, low-friction signal for fraud scoring without requiring any explicit customer action; helps enforce regulatory geo-restrictions such as sanctioned countries or licensing jurisdiction limits automatically; can be combined with device fingerprinting for stronger fraud signals.
Limitations
IP-based location can be inaccurate for VPN, proxy or mobile carrier NAT users, producing false signals; privacy regulations in some jurisdictions constrain how location data can be collected, stored and used; should never be the sole basis for a fraud or compliance decision given its inherent imprecision.
Use cases
Fraud risk scoring input alongside other signals; regulatory geo-restriction enforcement; localization of currency and payment method options.
OCR
Optical character recognition providers extract structured data such as names, document numbers, dates and addresses from photographed or scanned identity and business documents during onboarding, removing the need for customers to manually retype information the document already contains and reducing data-entry errors downstream.
Advantages
Meaningfully speeds up onboarding by auto-filling forms from document photos rather than requiring manual entry; reduces data-entry errors compared to manual transcription; integrates well with downstream KYC and KYB verification checks that need the extracted data fields.
Limitations
Extraction accuracy depends heavily on document image quality, lighting and the specific document format or country, requiring a fallback manual-entry path; some document types and non-Latin scripts are harder to extract reliably than standard passports or driving licences; still requires validation against source-of-truth registries rather than being trusted blindly.
Use cases
Automated document intake during KYC and KYB onboarding; invoice and receipt data extraction for expense or reconciliation tooling.
E-signature
E-signature services let merchants and partners execute legally binding agreements, such as merchant service agreements, processing terms and data processing addenda, entirely online, with an audit trail of who signed what and when. This removes a significant amount of friction and turnaround time from onboarding compared to physical or PDF-and-email signature workflows.
Advantages
Significantly speeds up legal workflow turnaround compared to print-sign-scan or courier-based processes; produces a tamper-evident audit trail including IP, timestamp and identity that supports legal enforceability; integrates well into automated onboarding flows, triggering next steps once a contract is signed.
Limitations
Legal enforceability rules for e-signatures vary by jurisdiction and document type, requiring legal review for cross-border use; some counterparties, particularly certain banks or regulators, may still require or prefer wet-ink signatures for specific document types; provider selection affects which jurisdictions and compliance standards such as eIDAS or the ESIGN Act are actually covered.
Use cases
Merchant services agreements and onboarding contracts; data processing addenda and partner agreements; internal HR and vendor contracts.
Cloud providers
AWS, Azure and Google Cloud provide the elastic compute, storage, networking and managed-service infrastructure that essentially every modern payment platform runs on, offering the ability to scale capacity up and down with demand rather than provisioning for peak load year-round. Each also offers its own compliance certifications such as PCI, ISO 27001 and SOC 2 that can materially simplify a platform's own compliance evidence gathering.
Advantages
Elastic scale means capacity can grow with demand rather than requiring large upfront hardware investment; provider-level compliance certifications such as PCI DSS, ISO 27001 and SOC 2 reduce the platform's own audit burden; managed services such as databases, queues and secrets management reduce operational overhead; global infrastructure footprint simplifies serving multiple regions.
Limitations
Cost governance requires active management, since cloud spend can grow unexpectedly without proper monitoring and budgeting discipline; multi-cloud or hybrid strategies add real operational complexity if pursued without a clear reason; some degree of vendor dependency is unavoidable once deeply integrated with provider-specific managed services.
Use cases
Hosting for essentially all modern PSP stacks; managed databases, queues and secrets management; multi-region disaster recovery and failover.
CDN
Content delivery networks cache and serve static assets, such as checkout page assets, merchant portal front-ends and documentation, from edge locations close to end users, reducing latency and absorbing traffic spikes before they reach origin servers. For checkout pages specifically, a fast, reliable CDN measurably affects conversion rates.
Advantages
Meaningfully improves global page load performance for checkout and portal front-ends; absorbs traffic spikes and some classes of DDoS attacks before they reach origin infrastructure; reduces origin server load and bandwidth costs for static assets; most providers include TLS termination and WAF capabilities.
Limitations
Cache invalidation for frequently updated assets or configuration requires careful cache-control strategy to avoid serving stale content; adds an additional layer to debug when investigating performance or content issues; misconfigured caching of dynamic or sensitive content is a genuine security risk that must be actively guarded against.
Use cases
Checkout page and merchant portal static asset delivery; documentation and marketing site hosting; DDoS mitigation for public-facing endpoints.
Secure storage
Encrypted object and key storage services hold sensitive documents, backups and cryptographic material with strong access controls, audit logging and, in many cases, compliance certifications that a payment platform can lean on directly rather than building equivalent controls from scratch. This is typically where KYC documents, signed contracts and encryption keys ultimately live at rest.
Advantages
Compliance-friendly by design, with audit logging and access control features that map directly to regulatory evidence requirements; encryption at rest is handled by the provider with well-tested implementations rather than custom code; versioning and lifecycle policies simplify retention and secure deletion requirements.
Limitations
Introduces a dependency on the provider's availability and access-control configuration being set correctly, since misconfigured storage buckets are a common real-world breach vector; retrieval latency for archival storage tiers can be significant if not accounted for in workflow design; cross-region replication for resilience adds cost and configuration complexity.
Use cases
KYC and KYB document storage; encrypted backups and disaster recovery archives; cryptographic key and certificate storage.
