Moving from WSO2 API Manager: what regulated teams need from their next gateway

WSO2 API Manager has had a long run in regulated enterprises, and for many teams it remains the first name that comes up when evaluating a WSO2 API Manager alternative. It offers an on-premises deployment model, a developer portal, a configurable policy engine, and a component-level separation between the gateway runtime and the key management surface. When most alternatives were cloud-first or required expensive system integrator work to assemble, WSO2 was often the only credible choice for banking, healthcare, and government teams that needed API management running entirely inside their own boundary.

That period is closing. The problems showing up in WSO2-based programs today are not version gaps or missing configuration options. They are architectural decisions that compound into operational overhead at a pace that is hard to justify as teams modernize their platforms. Add the requirement to support AI agents accessing APIs through the Model Context Protocol, and WSO2's component model creates problems that have no clean fix within the product.

A genuine WSO2 API Manager alternative in a regulated environment does not just mean a faster binary. It needs to satisfy the same compliance, audit, and access control requirements that led teams to choose WSO2 in the first place, and it needs to handle non-human API traffic without a separate deployment or a second credential system.

Why WSO2's architecture creates compounding overhead

WSO2 API Manager is built from multiple loosely coupled components: the API Manager core, a Traffic Manager for throttling, a Key Manager for OAuth2 token issuance, an optional Microgateway for edge deployments, and a separate Analytics layer if you want usage dashboards. In practice, keeping these in sync across environments involves patching JVM versions, running WSO2 Update Manager (WUM) passes, aligning API product state between the gateway and the key manager, and coordinating rolling updates without downtime. That coordination occupies a meaningful share of platform engineering time, and incidents involving component desynchronization are common enough that most production WSO2 deployments have runbooks specifically for recovering from it.

The JVM dependency also sets a resource floor that matters operationally. A production WSO2 deployment typically requires multiple gigabytes of heap across its components, takes tens of seconds to reach steady-state throughput after a restart, and needs careful GC tuning to avoid latency spikes during traffic bursts. For teams running on-premises with constrained hardware, or trying to deploy into a Kubernetes namespace with per-pod resource limits, the overhead is difficult to fit neatly.

Neither of these is a bug. They are expected costs of a product designed for an era when those constraints were reasonable. The more significant gap has emerged recently: WSO2 API Manager predates the Model Context Protocol by nearly a decade. Teams now running AI agents that need structured, authenticated access to internal APIs face an unattractive set of options: expose raw endpoints through a sidecar, build a custom MCP adapter on top of the existing gateway, or deploy a second gateway purpose-built for agent traffic. Each path adds exactly the coordination overhead the platform was supposed to eliminate.

What a genuine WSO2 API Manager alternative looks like

Zerq's architecture starts from different constraints. The gateway runtime, management API, MCP endpoints, and audit logging all run inside a single Go binary. There is no Traffic Manager to synchronize, no separate Key Manager, no JVM to tune. The binary starts in under a second and runs comfortably in containers with low memory allocation. All configuration and audit data is stored in a MongoDB instance you own: MONGODB_URI points to your cluster, and nothing is sent to Zerq's systems during normal operation.

One binary, two consumer types

The same Zerq process serves traditional REST clients and AI agents. Both use the same credential model: an X-Client-ID header, an X-Profile-ID header, and the authentication material for the profile's configured auth type. Both are subject to the same rate limits, IP restrictions, and method constraints configured in the management UI. Both generate structured request log entries with the same field schema.

An AI agent connecting via MCP initializes a session against the gateway's MCP endpoint (default: /mcp), receives a tool catalog constrained to the collections the client is authorized to access, and calls execute_endpoint to invoke a real API. The call travels through the same middleware stack as a direct HTTP request, with rate limiting, auth validation, and request logging all included, and no separate deployment or credential path required. This is how Zerq delivers one gateway for REST and AI agents without a second control plane.

Access control that maps to compliance requirements

WSO2's access control model is powerful but expressed in a policy language that requires specialist knowledge: mediation flows, XACML entitlements, custom throttling tier YAML. Zerq's model is flatter and more auditable.

Every API consumer is a Client. Each client authenticates through one or more Profiles. Each client's traffic is governed by an attached Policy. A profile defines the auth method (token, JWT, OIDC, or mTLS), optional IP restrictions in CIDR notation, and optional HTTP method limits. A policy sets rate limit intervals (1m, 5m, 1h) and long-window quotas (1d, 7d, 30d).

Here is how a banking team onboards a Third-Party Provider (TPP) with mTLS authentication (the standard for PSD2 compliance) using this model:

Step 1: Create the client

Go to Clients in the management sidebar. Click New Client.

Name: tpp-finco-ltd
Collection access: select accounts and payments (and nothing else)
Policy: attach TPP Standard (for example: 500 req/min, 100,000 req/month)
Click Create

Step 2: Add the mTLS profile

Inside the client, click Add Profile.

Name: production
Auth Type: mTLS
Allowed Methods: GET, POST (no DELETE, no PUT)
IP Restrictions: 203.0.113.0/24 (the TPP's registered egress range)
Active: yes
Click Save

Copy the X-Client-ID and X-Profile-ID values immediately. Every request from this partner carries these identifiers, making it unambiguous in the audit trail who called what and when.

Step 3: Give the TPP access to the developer portal

In the client settings, add the TPP's technical contact email to the portal access list. They receive a magic-link sign-in and see only the accounts and payments products. Nothing else in the catalog is visible to them.

Step 4: Validate before go-live

# Allowed path: should return 200
curl -i https://api.yourbank.com/accounts/v1/me \
  -H "X-Client-ID: tpp-finco-ltd" \
  -H "X-Profile-ID: production" \
  --cert finco.crt --key finco.key

# Method not in profile: should return 405
curl -i -X DELETE https://api.yourbank.com/accounts/v1/me \
  -H "X-Client-ID: tpp-finco-ltd" \
  -H "X-Profile-ID: production" \
  --cert finco.crt --key finco.key

# Request from outside the CIDR range: should return 403
curl -i https://api.yourbank.com/accounts/v1/me \
  -H "X-Client-ID: tpp-finco-ltd" \
  -H "X-Profile-ID: production" \
  --cert finco.crt --key finco.key \
  --interface 198.51.100.5

Each of these outcomes is logged. The 405 and 403 responses appear in the request log with X-Client-ID: tpp-finco-ltd and the reason code, giving your security and compliance teams a complete picture of both allowed and denied access patterns.

Management RBAC with separation of duties

WSO2 provides a role model tied to its own user store or an external LDAP/OIDC connection, but the separation between platform admin and audit-only access is often custom configuration work. Zerq uses OIDC for the management surface directly, with four role tiers enforced by the backend: viewer, modifier, auditor, and admin.

The auditor role exists specifically to give compliance and security teams read access to audit and request log views without the ability to modify any configuration. The backend enforces this on every API call. The frontend hides UI actions that a role cannot take, but the authorization is always resolved server-side.

Configuration example:

# Management OIDC (backend/.env)
OIDC_ENABLED=true
OIDC_ISSUER_URL=https://auth.yourorg.com/realms/platform
OIDC_AUDIENCE=zerq-management
OIDC_ROLE_CLAIM_PATH=resource_access.zerq-management.roles

# Role name mappings: match the role names in your IdP
OIDC_VIEWER_ROLES=zerq-viewer
OIDC_MODIFIER_ROLES=zerq-modifier
OIDC_AUDITOR_ROLES=zerq-auditor
OIDC_ADMIN_ROLES=zerq-admin

Assign zerq-auditor to the compliance team's IdP group. They can query request logs filtered by partner, product, and time range directly from the management UI. They cannot create or delete clients, profiles, workflows, or credentials.

Audit data in your boundary

All request logs and management audit events are written to your MongoDB instance. There is no separate analytics component to deploy, no data export pipeline to build, and no dependency on Zerq's infrastructure to query historical data. This means one data residency answer for regulators, not two or three depending on which WSO2 component stored what, and no third-party control plane touching production traffic logs.

The observability dashboard in the management UI reads from the same MongoDB collections, giving real-time request volume, error rates, and partner-level breakdowns without additional infrastructure.

What this looks like in practice

A regional bank running WSO2 API Manager 4.x for its open banking partner ecosystem initiated a migration after failing two consecutive internal compliance reviews. The audit team needed per-TPP request logs showing authenticated access per endpoint, and WSO2's analytics data required a two-step extraction process: pull from the analytics database, then join with Key Manager records to map OAuth2 client IDs to registered business identities. The process took two to three days per audit cycle and produced outputs that required manual reformatting to match the regulator's template.

After completing the migration to Zerq, which ran in parallel with the existing WSO2 deployment for four weeks before cutover, each TPP's business identity mapped directly to a client. The request log for every call carried X-Client-ID as the partner identifier, the endpoint path, the HTTP method, the HTTP status returned, and a timestamp. The compliance team queried request logs directly from the management UI using their auditor role accounts. No data extraction, no joins, no reformatting.

The platform engineering time invested was roughly five days: recreate the client/profile structure for each active TPP, validate one allow path and one deny path per TPP, test the mTLS certificate chain end to end, then cut DNS to the new gateway. WSO2 remained available for rollback during the first two weeks after cutover.

Closing

WSO2 API Manager is a competent product for the era it was designed for. The gaps that affect regulated teams today are structural: the component model is the architecture, the JVM resource requirement is the runtime, and MCP support is not in the product roadmap in a way that resolves the second-gateway problem. Zerq gives you a single Go binary that handles REST clients and AI agents through the same credential model and audit trail, a flat access control model that maps directly to compliance reporting, management RBAC with an audit-only role for your compliance team, and request logs stored in your own MongoDB with no analytics component, no data export pipeline, and no third-party data residency complications.

Zerq is an enterprise API gateway built for regulated industries — one platform for API management, AI agent access, compliance audit, and developer portal, running entirely in your own infrastructure. See how it works or request a demo to walk through your specific requirements.