Salesforce Certified MuleSoft Developer II – Complete Winter '26 Guide

Advanced DataWeave: Functions and Modules

DataWeave II advanced features: pattern matching (match/case for type-based branching), named functions (fun myFunc(arg) = ...), lambda functions (vars), and custom modules (import from external .dwl files). Complex scenarios: transforming nested arrays, handling nulls with default and orElse, type coercion. The exam presents complex transformation requirements and tests whether the developer can write efficient, readable DataWeave code — understanding when to use map vs reduce vs mapObject is critical.

Batch Processing in Mule

Batch Job scope processes large datasets in records. Phases: On Complete (runs after all records processed), On Input (optional pre-processing), Batch Steps (process each record). Batch Aggregator accumulates records before processing — commit size defines how many records are committed together. Failed records can be routed separately. Database.Stateful equivalent: use Batch Job Record Variables to carry state. The exam tests Batch Job configuration for high-volume data processing scenarios.

API Security: Policies and OAuth

Anypoint API Manager applies security policies to deployed APIs. Common policies: Client ID Enforcement (all clients must register and send client ID), OAuth 2.0 Token Enforcement (validate Bearer tokens), IP Allowlist, Rate Limiting (throttle by client or overall). Policies are applied through API Manager and injected into the runtime automatically — no code changes needed. The exam tests which policy combination to use for a given security requirement (authentication + authorisation + throttling).

Performance: Scatter-Gather and Cache Scope

Scatter-Gather executes multiple routes in parallel and aggregates responses — ideal for fan-out calls where all responses are needed. Each route runs concurrently; Scatter-Gather waits for all routes to complete before aggregating. Cache Scope stores responses for a configurable TTL — reduces redundant external calls. Reconnection strategies handle transient connectivity failures. Async processing (VM connector, queues) decouples processing speed from response time. The exam tests when each performance pattern is appropriate.

CI/CD with Anypoint: Maven and CloudHub Deployment

Anypoint Maven Plugin enables automated deployment in CI/CD pipelines. pom.xml configuration includes CloudHub credentials, region, and worker configuration. Anypoint CLI provides command-line deployment and management. API Autodiscovery links a deployed Mule app to an API definition in API Manager — enables policy enforcement. The deployment pipeline: unit tests (MUnit) → build JAR → deploy to CloudHub → run integration tests → promote to production. The exam tests CI/CD pipeline design and Maven plugin configuration.

Advanced DataWeave

Go beyond basic mappings: know how to use modules (Arrays, Strings, Math), pattern matching, recursive functions, and how to write reusable DataWeave modules. Know how to handle complex nested JSON and XML transformations.

Async & Batch Processing

Know Batch Jobs in Mule 4: Batch Job scope, Batch Step, Batch Aggregator, and On Complete phases. Understand when to use batch processing vs. scatter-gather for parallel processing of large data sets.

API Security Policies

Know how to apply policies in API Manager: Rate Limiting, JWT Validation, OAuth 2.0 (client credentials, authorization code), CORS, and IP whitelist. Understand policy ordering and how custom policies are built.

Advanced Deployment Strategies

Know the difference between CloudHub 1.0, CloudHub 2.0, and Runtime Fabric deployment models. Understand zero-downtime deployments, persistent queues, and how to configure multiple workers for HA.

Performance Tuning

Know how to tune thread pools (Grizzly, CPU intensive, CPU lite, I/O), configure watermark-based polling, and use caching (Object Store) to reduce redundant API calls in Mule applications.