# API Autodiscovery and API proxies

*MuleSoft Developer Study Guide · Deploying and Managing APIs and Integrations · Last updated October 28, 2026 · https://www.certifyforce.com/study-guide/mulesoft-developer/deploying-and-managing-apis-and-integrations/api-autodiscovery-and-api-proxies*

Pair a Mule app with an API Manager instance through API Autodiscovery (apiId, an HTTP Listener flowRef, environment credentials), predict Gatekeeper's 503 after a redeploy, and choose a basic endpoint or a generated API proxy and its type.

- Certification: Salesforce MuleSoft Developer
- Exam section: Deploying and Managing APIs and Integrations
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-developer

**Official exam objective:**

> Manage APIs using separate proxies and auto-discovery.

## What the exam expects

- Write the `api-gateway:autodiscovery` element: `apiId` is the API ID API Manager generated for the instance, `flowRef` names a flow whose source is an HTTP Listener.
- Configure the runtime's Anypoint Platform credentials and explain why environment credentials only pair with APIs in that environment.
- Explain the `503` clients receive right after a redeploy of a paired app.
- Choose a basic endpoint (the Mule app is its own proxy) or a deployed proxy application (non-Mule or closed-code backends).
- Name what a RAML/OAS proxy adds over an HTTP proxy.

Key terms:
- **API instance**: a managed API in API Manager, identified by its generated API ID.
- **Autodiscovery**: the element that pairs ("tracks") a deployed Mule app with one API instance so it downloads policies and sends analytics.
- **Basic endpoint**: the Connect to existing application option; your own Mule app acts as the proxy.
- **API proxy**: a Mule app that API Manager generates and deploys in front of a backend.
- **Gatekeeper**: the runtime mechanism that blocks a tracked resource until its policies are applied.

Everything here is Mule Gateway, the runtime API Manager uses for APIs on Mule; Omni Gateway is a separate gateway instance type and not what these questions test ([Add API Instances](https://docs.mulesoft.com/api-manager/latest/add-api-instances)).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| `apiId` value | API ID generated by API Manager for the instance | [Configuring Autodiscovery in Mule 4](https://docs.mulesoft.com/mule-gateway/mule-gateway-config-autodiscovery-mule4) |
| `flowRef` flow | Must use an HTTP Listener | [Configuring Autodiscovery in Mule 4](https://docs.mulesoft.com/mule-gateway/mule-gateway-config-autodiscovery-mule4) |
| One API, one autodiscovery | Only one at a time | [API Autodiscovery](https://docs.mulesoft.com/mule-gateway/mule-gateway-autodiscovery-overview) |
| Recommended credentials | Environment client ID and secret | [Organization Credentials in Mule 4](https://docs.mulesoft.com/mule-gateway/mule-gateway-org-credentials-mule4) |
| CloudHub credential properties | `anypoint.platform.client_id`, `anypoint.platform.client_secret` | [Organization Credentials in Mule 4](https://docs.mulesoft.com/mule-gateway/mule-gateway-org-credentials-mule4) |
| Gatekeeper status code | `503 - Service Unavailable` | [Enhancing Security with Gatekeeper](https://docs.mulesoft.com/mule-gateway/mule-gateway-gatekeeper) |
| Gatekeeper default | `flexible` for Mule 4.1.0 and later | [Enhancing Security with Gatekeeper](https://docs.mulesoft.com/mule-gateway/mule-gateway-gatekeeper) |
| CloudHub proxy default size | 0.1 vCores, 500 MB | [Deploy Your API Proxy](https://docs.mulesoft.com/api-manager/latest/proxy-latest-concept) |
| Proxy Upstream URL | Required for Deploy a proxy application | [Adding a Mule Gateway API Instance](https://docs.mulesoft.com/api-manager/latest/create-instance-task-mule) |

## Check yourself

- Why does a malformed policy leave a paired app answering `503`?
- When must you also set `anypoint.platform.base_uri` and `anypoint.platform.analytics_base_uri`?
- What does Gatekeeper do with a resource that is not linked to an API instance?
- Why can one API be paired with only one autodiscovery instance at a time?
- What are the default vCores and memory of a CloudHub proxy?

## Sources

- [API Autodiscovery](https://docs.mulesoft.com/mule-gateway/mule-gateway-autodiscovery-overview)
- [Configuring Mule Gateway API Autodiscovery in a Mule 4 Application](https://docs.mulesoft.com/mule-gateway/mule-gateway-config-autodiscovery-mule4)
- [Configuring Organization Credentials in Mule Runtime 4](https://docs.mulesoft.com/mule-gateway/mule-gateway-org-credentials-mule4)
- [Enhancing Security with Gatekeeper](https://docs.mulesoft.com/mule-gateway/mule-gateway-gatekeeper)
- [Adding a Mule Gateway API Instance](https://docs.mulesoft.com/api-manager/latest/create-instance-task-mule)
- [Configure Proxies for Your APIs](https://docs.mulesoft.com/api-manager/latest/api-proxy-landing-page)
- [Reviewing API Proxy Benefits and Impacts](https://docs.mulesoft.com/api-manager/latest/proxy-advantages)
- [Deploy Your API Proxy](https://docs.mulesoft.com/api-manager/latest/proxy-latest-concept)
- [Add API Instances](https://docs.mulesoft.com/api-manager/latest/add-api-instances)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 7 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Developer pack (USD $19): https://www.certifyforce.com/practice-exams