Exposing APIs the Right Way

An API gateway is your first line of defense and the single choke point for enforcing partner access. It handles TLS termination, token validation, routing, and logging—controls you can’t reliably bolt on later. Without it, you end up with scattered configs, fragile integrations, and no clear perimeter.

This guide walks through practical gateway patterns, the security policies you must enforce, routing approaches that scale, and the observability needed for troubleshooting and audits. The goal: give you a clear path to make your API production-ready for partner onboarding in 30 days.

Core Models for Exposing APIs

There isn’t a single “right” way to present an API. Instead, organizations typically choose from a few recurring gateway models—each with different trade-offs in security, performance, and operational control. Below are the three most common patterns and when to use them.

Direct Exposure via API Gateway

Backend services are fronted directly by a managed API gateway (AWS API Gateway, Apigee, Kong, Azure API Management). The gateway terminates TLS, applies policies, and routes requests to downstream services or serverless functions.

Direct exposure via API Gateway is best for teams that want to move quickly, minimize infrastructure operations, and leverage the built-in integrations cloud vendors provide. This model works well for greenfield APIs, internal platforms, or ecosystems where the gateway’s native IAM integration is sufficient.

Pros

• Fully managed control plane and data plane—no patching or upgrades.

• Tight native integrations (e.g., AWS → Lambda, DynamoDB; GCP → Cloud Run).

• Built-in support for quotas, throttling, and JWT validation.

Cons

• Limited control over the TLS stack and cipher configuration.

• Bound by vendor constraints (e.g., payload size, timeout limits).

• Harder to implement advanced traffic policies like custom mTLS revocation checks.

Reverse Proxy Front + Gateway

All incoming traffic first terminates at a self-managed reverse proxy such as NGINX or Envoy. The proxy enforces advanced TLS/mTLS policies, IP allowlists, custom authentication, or routing logic before forwarding the request to a managed API gateway.

Reverse Proxy and Gateway model is ideal when compliance or regulatory requirements demand full control over TLS, certificate lifecycle, OCSP/CRL validation, or non-standard routing logic that a managed gateway doesn’t natively support. It’s also a good fit if you want a consistent ingress model across hybrid or multi-cloud deployments.

Pros

• Fine-grained control of TLS, cipher suites, and certificate revocation policies.

• Can centralize certificate issuance, renewal, and logging before traffic reaches the managed gateway.

• Extensible with plugins/modules for authentication, rate limiting, or observability.

Cons

• Adds an extra network hop, which increases latency.

• Expands the operations footprint—you must patch, scale, and monitor the proxy tier.

• Debugging failures becomes more complex since errors may originate at proxy or gateway layers.

Multi-Layer: Edge CDN + Gateway + Backend

Pattern: Requests first traverse a Content Delivery Network (CDN) such as CloudFront, Akamai, or Fastly, which provides caching and global traffic distribution. From there, traffic is routed to the API gateway for policy enforcement and finally to backend services.

Such model is designed for public APIs with high request volume and globally distributed consumers. This model is especially valuable when latency and DDoS resilience are critical, or when your partners are geographically far from your gateway’s region.

Pros

• Built-in caching at global Points of Presence (POPs) reduces latency and backend load.

• DDoS protection and WAF rules applied at the edge before traffic ever reaches your gateway.

• Can offload static or semi-static responses (e.g., OpenAPI docs, metadata endpoints) at the CDN layer.

Cons

• More moving parts—traffic flows through at least three distinct layers (CDN, gateway, backend).

• Harder to trace or debug failed requests due to layered caching and error handling.

• Additional cost for CDN services, especially if egress traffic is high.

Choosing the Right Gateway

When designing your API architecture, the gateway is more than just a router—it’s the control point for security, scalability, and developer productivity. Selecting the right gateway pattern requires weighing trade-offs in transport security, authorization enforcement, observability, and long-term maintainability.

Choosing an API gateway isn’t just about price or vendor preference—it’s about matching protocol support, scalability, security, and ecosystem fit to your platform needs. Below are the critical evaluation factors every engineering team should consider.

tip

Multi-gateway strategies: Use separate gateways for internal, partner, and public APIs; or run dedicated clusters for sandbox vs. production traffic to improve reliability and compliance.

Performance and Scalability

• Measure latency overhead, throughput, and request concurrency.

  These factors become critical in microservices architectures and during peak partner traffic.

• Verify support for auto-scaling and orchestration integration (Kubernetes, ECS, Nomad).

• Open-source options like NGINX are resource-efficient, while GWs like Kong and APISIX provide built-in horizontal scaling for cloud-native workloads.

Security Features

• Ensure full support for modern security protocols: OAuth 2.0, JWT validation, mTLS, or DPoP.

• Gateways should integrate with external identity providers to enforce fine-grained RBAC/ABAC policies.

• Look for rate limiting, IP allow/deny lists, replay attack prevention, and automated certificate lifecycle management to cover enterprise-grade needs.

Protocol Support & Edge Functionality

• Confirm first-class support for REST, gRPC, GraphQL, and protocol translation for legacy backends.

• Check for edge functionality: request/response transformation, payload inspection, CORS enforcement, caching, metrics, and custom logging hooks.

• Gateways that support edge functions or Lua/JavaScript plugins let you enforce business rules closer to the request origin.

Deployment Model: Managed vs. Self-Hosted

• Cloud-managed gateways: quick launch, native cloud integration, and automatic scaling—but at the cost of vendor lock-in and limited extensibility.

• Open-source/self-hosted gateways: flexible deployment (on-prem, hybrid, multi-cloud), custom plugins, and no ecosystem lock—but require ongoing ops ownership.

Match your choice to compliance requirements, team expertise, and migration strategy.

Developer Experience and Ecosystem

• High-quality documentation, SDKs, and quickstart guides reduce onboarding friction for internal teams and external partners.

• Features like developer portals, self-service key provisioning, and CI/CD integrations directly affect time-to-market.

• A strong open-source community and plugin ecosystem ensures faster troubleshooting, broader extension options, and long-term sustainability.

How to Choose the Right Gateway

1. Define traffic and protocol requirements.

   REST-only workloads? Any gateway works. Need gRPC, Kafka, or GraphQL? Make sure it's supported.

2. Set security priorities.

   For financial, healthcare, or regulated industries, prioritize gateways with mTLS, certificate automation, and audit trails.

3. Consider deployment constraints.

   Managed gateways for speed and simplicity; open-source for hybrid/multi-cloud flexibility.

4. Plan for scalability.

   If partner growth or multi-region deployments are expected, choose K8s-native scaling gateways.

5. Evaluate developer experience.

   A strong developer portal, SDKs, and automation hooks improve partner onboarding and speed up integrations.

6. Balance cost and maintenance.

   Managed gateways simplify ops but may scale costs quickly; open-source saves at scale but adds operational overhead.

Common Pitfalls in Gateway Selection

• Vendor lock-in

  Cloud gateways often bind your API policies and IAM to their ecosystem.

• Over-reliance on built-in features

  If you need custom business logic or protocol transformation, pick an extensible open-source gateway.

• Protocol mismatches:

  Failure to handle SOAP, Kafka, or legacy APIs can stall integrations.

• Poor developer onboarding

  Weak documentation or missing SDKs delay partner integrations.

• Ignoring future scale

  Choosing gateways without multi-region or container-native support can cause migration headaches later.

Security Considerations at the Gateway

The API gateway serves as the primary enforcement point for transport security and token-level trust, making it the first and most critical line of defense for any partner-facing API. Every request crossing this perimeter should be carefully validated to ensure that only authenticated and authorized clients reach your backend services. Strong transport security begins with enforcing TLS 1.2 or higher, disabling legacy versions and weak cipher suites, and conducting regular configuration audits, such as SSL Labs scans, to maintain compliance and resilience against emerging threats.

For high-assurance B2B and regulated APIs, mutual TLS (mTLS) is essential. Client TLS sessions should be terminated either at the gateway itself or at a fronting reverse proxy, and each certificate must be validated against a trusted CA bundle, whether managed centrally via an enterprise PKI or specialized services like AWS ACM Private CA. Where possible, implement revocation checks via CRL or OCSP to immediately detect compromised certificates. These measures ensure cryptographic proof of client identity and help prevent unauthorized access even if a token is leaked.

Beyond transport security, protecting APIs from application-layer attacks is critical, especially for public partner APIs. Integrating a Web Application Firewall (WAF) or Intrusion Detection System (IDS) at or near the gateway adds an additional enforcement layer. A WAF can block common threats such as SQL injection, cross-site scripting, or automated bot traffic before it reaches your backend, while an IDS can detect suspicious traffic patterns or anomalies indicative of attempted breaches. Modern API gateways often offer native WAF support (e.g., AWS WAF with API Gateway or Cloudflare WAF at the edge), and traffic logs can be forwarded to SIEM/IDS platforms for real-time monitoring and incident response.

It is equally important to disable default or unmanaged endpoints. For instance, AWS API Gateway exposes execute-api hostnames by default, which could allow clients to bypass custom security controls. Once custom domains are in place, these defaults should be turned off, ensuring that all traffic is funneled through properly secured, observable, and policy-enforced entry points.

By combining TLS enforcement, mTLS validation, WAF/IDS protections, and the removal of unmanaged endpoints, your gateway becomes a robust control plane—safeguarding partner integrations while providing a clear audit trail of all requests. This multi-layered approach protects against both transport-level and application-layer threats, forming a strong foundation for secure, scalable, and compliant API exposure.

Design Patterns for Routing

How you structure API routes is more than a convenience for developers—it directly impacts security, auditability, and operational clarity. Using custom domains consistently ensures that partners never interact with vendor-generated hostnames, which can inadvertently bypass policy enforcement. For example, instead of exposing the default xyz.execute-api.aws.com, front your APIs with a domain like api.company.com, providing both branding consistency and a single point of control.

Environment separation is equally important. Rather than relying on path-based tricks like /v1/sandbox/ within a production domain—which can leak test traffic into production logs and confuse clients—use subdomains per environment, such as api.sandbox.company.com and api.partner.company.com. This also allows distinct WAF/IDS policies for each environment: you can apply stricter rules on public-facing endpoints while giving internal or sandbox APIs more relaxed logging and throttling.

API versioning should also be intentional. URI-based versioning (/v1/accounts) is the most common approach and keeps clients and servers aligned. In some cases, subdomain versioning (e.g., v1.api.company.com) is warranted when major versions introduce semantic changes that might affect routing, authorization, or rate-limiting logic. Regardless of your method, ensure that all traffic flows through the mTLS-enabled gateway domain. This allows WAF, IDS, and gateway policies to consistently enforce security and prevents any traffic from bypassing inspection layers.

For public partner APIs, placing WAF or IDS policies at the gateway or at the CDN/edge provides early detection and mitigation of threats. For instance, a CDN with WAF integration can stop volumetric attacks or block common injection patterns before requests reach your gateway, while an IDS can alert your security team to anomalous patterns that could indicate attempted compromise.

Observability and Diagnostics at the Gateway

A gateway is more than a traffic router—it is the source of truth for who accessed your APIs, when, and under what conditions. Without proper observability, you can’t prove compliance, resolve partner disputes, or trace security incidents. Good instrumentation turns the gateway into both a security control and an operational safety net.

The first step is tying each request to a verifiable identity. When using mutual TLS, log the client certificate’s subject DN and fingerprint to create a cryptographic audit trail. Pair these with token metadata—such as the JWT jti—so requests can be correlated across gateways, microservices, and backend layers. This makes it possible to diagnose access failures quickly and demonstrate which partner invoked which API in a regulated setting.

Error monitoring is equally important. Distinguish between authentication errors (401), authorization failures (403), and backend issues (5xx). This separation avoids wasted time on blind debugging and provides clear signals for whether the issue lies with a partner’s credentials, your policies, or downstream systems. Feeding these error streams into dashboards highlights patterns like repeated failed logins or sudden spikes in backend failures.

Distributed tracing completes the picture. Propagate W3C traceparent headers—or equivalent—so that requests can be followed across the entire path, from partner client through CDN, gateway, and backend services. In multi-layer deployments, this visibility is what turns a vague “the API is slow” complaint into a pinpointed diagnosis.

Finally, treat gateway logs and metrics as part of a holistic monitoring stack. Forward them to SIEMs, WAF dashboards, or IDS platforms to correlate security signals with operational data. This integrated view lets you catch anomalies such as abnormal traffic patterns, repeated token misuse, or suspicious certificate activity before they become outages or breaches.

Done right, observability transforms the gateway from a black box into a control tower: one that not only routes traffic, but also enforces trust, accelerates incident response, and builds confidence with partners.

Conclusion

A solid gateway setup is what makes partner APIs secure, reliable, and supportable. Start simple with a managed gateway and custom mTLS domain, then add layers—reverse proxy, CDN, WAF/IDS—only when scale or regulatory needs demand it. Always enforce TLS 1.2+, disable unmanaged endpoints, and externalize policies so they scale across APIs.

Make observability a first-class concern: log certificate and token identities, track error trends, and propagate trace headers. Automate certificate rotation and stick to open standards to avoid lock-in.

The right pattern depends on your context—speed for MVPs, control for regulated ecosystems, or global resilience for public APIs. Whichever you choose, the principle is the same: one choke point, strict security, clear routing, and full visibility. That’s the foundation of partner trust.

Want to see these patterns in action? Our 30-day playbook shows you exactly how to take an API from concept to production-ready partner onboarding — mTLS, scopes, roles, and client registration included.

Practical Guide

Onboard Your First Partner in 30 Days - No Fluff, Just Code

Get the practical developer playbook with weekly steps, real configs, and copy-ready code to build, secure, and distribute your APIs fast.

Access Now →