Updated for Winter ’26
Last Updated: November 2025 · Exam Code: Mule-Dev-301 · Version: Winter ’26
This guide reflects the latest Salesforce MuleSoft Developer II exam outline (Mule-Dev-301), including updated emphasis on modular Maven builds, production-ready API policies, observability & logging, ObjectStore-based reliability, and TLS / OAuth2 security patterns.
⚡ What’s Different at the MuleSoft Developer II Level?
MuleSoft Developer II moves beyond basic Mule 4 projects and tests your ability to build and operate production-grade integrations in a DevOps environment. Compared to MuleSoft Developer I, expect:
More focus on API autodiscovery, policy configuration, caching and versioning of API artifacts.
Health checks, centralized logging, log levels, message correlation and monitoring in Anypoint Platform.
Maven-based pipelines, automated deployments, libraries, custom policies and SDK-based components.
Secure properties, TLS, OAuth2, ObjectStore, resilient message flows and fault-tolerant HTTP calls.
Salesforce MuleSoft Developer II Exam Guide
Exam Code: Mule-Dev-301 · Senior-Level Integration Developer
Learn the complete MuleSoft Developer II syllabus – domains, weightage, prerequisites, study strategy and scenario-based sample questions to pass the exam on your first attempt.
📊 Mule-Dev-301 Exam at a Glance
Note: Official details (duration, fees, passing score and outline) are published on the Salesforce MuleSoft Developer II credential page and exam guide. Always double-check there for the latest updates before booking.
🎯 Exam Objectives & Weightage (Mule-Dev-301)
1. Expose Production-Ready Anypoint Platform–Managed APIs
13%Design and implement APIs that are managed through Anypoint Platform and suitable for production use, including policies, caching, callbacks and autodiscovery.
- Versioning of API-related artifacts and backward compatibility.
- Configuring out-of-the-box and custom API policies (throttling, rate-limiting, header injection, etc.).
- Server-side caching of API responses using policies for performance.
- Implementing HTTP callbacks / webhooks for async integrations.
- Implementing API autodiscovery in Mule applications.
Expect scenario questions around choosing correct policies, designing for versioning and avoiding breaking changes, and when to use callbacks vs synchronous APIs.
2. Implement Maintainable & Modular Mule Applications + Maven Builds
25%Build modular, reusable Mule applications with clean Maven build configurations suitable for automated deployment pipelines and large-scale projects.
- Modularizing Mule apps using domains, libraries and shared resources.
- Optimizing Maven POMs and profiles for multiple environments.
- Automated deployments to Mule runtimes using Maven & CI/CD.
- Running MUnit tests from Maven builds and enforcing coverage.
- Building custom API policies.
- Implementing custom message processors using Mule SDK / XML SDK.
At 25% of the exam, you cannot pass without being strong in Maven builds, modularization and automated deployments.
3. Implement Monitorable Mule Applications
15%Make Mule applications observable with health checks, structured logging and meaningful monitoring signals.
- Exposing health-check endpoints from Mule applications.
- Effective logging strategies (correlation IDs, structured logs, log levels).
- Changing log levels at runtime; aggregating and analyzing logs.
- Monitoring apps and runtimes using Anypoint Platform or external tools.
- Implementing message correlation across HTTP calls.
Many questions are phrased as “operations is complaining that…” – think about log structure, correlation IDs and health checks that help SRE/DevOps teams.
4. Implement Performant & Reliable Mule Applications
27%Design integrations that scale, recover gracefully from failures and meet non-functional requirements for performance and reliability.
- ObjectStore persistence patterns for different Mule deployment options.
- Fault-tolerant, performant, traceable flows using VM and AnypointMQ connectors.
- Resilient HTTP invocations and handling HTTP status codes correctly.
- Validating data using the Validation module and XML/JSON schemas.
- Parallelizing integration logic with scatter-gather.
- Compensating transactions for partial failures in parallel flows.
- Client-side caching of API calls when appropriate.
This is the largest section of the exam. Practice many scenarios around retries, timeouts, bulk processing, scatter-gather and resilience patterns.
5. Secure Data at Rest & In Transit
20%Implement strong security practices around certificates, keys, encryption and authentication for Mule APIs and integrations.
- Secure, environment-dependent properties management (e.g., secure properties, configuration management).
- Creating, packaging and distributing keys and certificates.
- Exposing and invoking APIs over HTTPS.
- Implementing TLS mutual authentication (mTLS) on client and server.
- Configuring Basic Auth and OAuth2 with HTTP/REST connectors.
Many questions combine security + performance. Always think about least privilege, secure storage of secrets and avoiding hard-coded credentials.
📝 Sample Exam-Style Questions (Mule-Dev-301)
Try Before You Test
These questions are simplified, but reflect the scenario-based style of the real MuleSoft Developer II exam. Focus on understanding why the answer is correct.
Question 1 – Production-Ready API Policies
A team exposes an orders API managed by Anypoint Platform. During a flash sale, the backend system starts failing due to unexpected traffic spikes. As the MuleSoft Developer II, you must protect the backend while still allowing some requests to succeed for premium customers.
What is the best approach?
A) Increase worker size on the API implementation and restart.
B) Add a spike control policy combined with rate-limiting based on a client identification header.
C) Configure a client-side cache and disable the API autodiscovery to reduce platform overhead.
D) Remove authentication to reduce latency and improve throughput.
✓ Correct Answer: B) Spike control + rate limiting by client
Applying spike control and rate-limiting policies is aligned with production-ready management: the backend is protected while premium clients can still be prioritized using client identifiers.
Question 2 – Modularization & Maven Builds
Your company has 15 Mule APIs that share common error-handling flows and a custom logging strategy. Currently, each project duplicates this logic. The team wants a solution that reduces duplication and can be built and deployed through a central CI/CD pipeline.
What should you recommend?
A) Create a single giant Mule app with all APIs and deploy it as one artifact.
B) Implement a shared Mule library containing common flows and a custom policy, then reference it from each API’s Maven build.
C) Store the common error-handling XML in each project’s resources folder and let CI/CD copy it during build.
D) Move the error handling into API Manager policies only.
✓ Correct Answer: B) Shared Mule library + Maven reuse
Encapsulating common logic in a reusable Mule library and referencing it in each project’s POM is the recommended modularization pattern for large-scale, production-ready integrations.
Question 3 – Monitoring & Correlation
Operations teams report that when an order fails in a downstream system, they struggle to trace the corresponding flow through multiple Mule apps and HTTP calls. Each app logs different IDs and formats.
Which pattern best improves traceability?
A) Use random UUIDs in each app and log them separately.
B) Enable DEBUG logs globally and export all logs.
C) Implement a shared correlation ID propagated via headers and include it in all log messages.
D) Rely only on the Mule message ID automatically generated by each app.
✓ Correct Answer: C) Shared correlation ID pattern
MuleSoft best practices recommend using a correlation ID propagated across HTTP calls and consistently logged, enabling cross-application tracing in aggregated logs.
Question 4 – Reliability & ObjectStore
A Mule flow consumes messages from AnypointMQ and calls an external payment API. Occasionally, the payment API is unavailable, and messages must not be lost. They should be retried later with idempotency preserved.
What design meets these requirements?
A) Log failed requests and ask the business to re-send them manually.
B) Use ObjectStore to persist message state and configure retries with backoff; mark processed messages with an idempotency key.
C) Discard messages when the API fails and rely on AnypointMQ DLQ only.
D) Increase API timeout and assume the provider will eventually respond.
✓ Correct Answer: B) ObjectStore + retries + idempotency
Reliable design uses ObjectStore to persist state, retries with backoff and idempotency keys to avoid duplicate payments when the API comes back online.
Question 5 – TLS & OAuth2 Security
A financial institution requires that all inbound traffic to a Mule API is encrypted with TLS and that clients present both a certificate and OAuth2 access token. The API should validate the client certificate and then authorize calls using scopes.
Which configuration aligns with this requirement?
A) HTTPS listener only; validate scopes in custom code.
B) HTTPS listener with TLS + mTLS, plus OAuth2 policy in API Manager enforcing scopes.
C) Plain HTTP with OAuth2 policy only.
D) HTTPS listener with Basic Auth configured in Anypoint Studio only.
✓ Correct Answer: B) TLS + mTLS + OAuth2 policy
The combination of HTTPS with mutual TLS and API Manager’s OAuth2 policy provides both strong client authentication (certificates) and authorization (scopes).
💡 Exam Tip: The real exam questions are longer and more detailed. Pay attention to constraints around DevOps, SLAs, security and operations – they usually reveal the correct pattern.
📚 Study Plan & Resources (4–6 Weeks)
Recommended Learning Path
This plan assumes you already hold MuleSoft Developer I and have solid Mule 4 experience. Adjust pace based on your background.
- Revisit Mule 4 fundamentals (flows, error handling, DataWeave).
- Study the official exam guide and outline each domain & sub-topic.
- Start the courses:
– Anypoint Platform Development: Production-Ready Development Practices (DEX660)
– Anypoint Platform Development: Production-Ready Integrations (DEX670)
- Build at least 2–3 production-style APIs with API Manager policies.
- Implement ObjectStore patterns, retries and scatter-gather.
- Configure Maven builds, profiles, and CI-style deployments (even if locally simulated).
- Practice logging, health checks, and dashboards in Anypoint Platform.
- Take at least 2–3 full-length practice exams in timed mode.
- Track weak domains (often security, Maven builds or observability).
- Revisit DEX660/DEX670 labs and official documentation for those topics.
- Prepare a 1–2 page personal “cheat sheet” of patterns and best practices.
💡 Exam-Day Strategy
120 minutes for ~65 questions ≈ 1.8 minutes per question. Don’t spend more than 2.5 minutes on a single item; mark and come back.
Look for clues like “DevOps pipeline”, “must not lose messages”, “regulated industry” that push you toward specific patterns (ObjectStore, mTLS, retries, etc.).
Several answers may be technically valid. Pick the one that aligns with MuleSoft & Salesforce best practices around security, observability and maintainability.
Use the review screen to revisit questions from high-weight domains (performance, Maven builds). A single corrected question can move you across the 70% line.
❓ Salesforce MuleSoft Developer II – FAQ
1. Who is the MuleSoft Developer II exam for?
This certification targets senior MuleSoft developers who can independently build and operate production-ready Mule applications in a DevOps environment, focusing on performance, reliability, security and operations.
2. Is MuleSoft Developer I mandatory before MuleSoft Developer II?
Yes. The Salesforce MuleSoft Developer (Mule-Dev-201) certification is an official prerequisite for the MuleSoft Developer II exam. You must earn it before attempting Mule-Dev-301.
3. How hard is MuleSoft Developer II compared to Developer I?
Developer II is significantly harder. While Developer I focuses on building basic APIs and integrations, Developer II adds DevOps, observability, advanced reliability patterns and strong security. Most candidates report needing solid hands-on experience and multiple practice exams.
4. How many attempts can I take if I fail?
Salesforce uses standard certification retake policies (with waiting periods between attempts). Check the latest rules on the official Salesforce Credential & Webassessor pages before scheduling another attempt.
5. What score should I target to feel safe?
The official passing score is 70%. In practice, aim for at least 80%+ on multiple mock exams before the real test to create a buffer for tricky questions or exam-day nerves.
6. Which domains should I prioritize?
Based on the exam outline, the heaviest domains are:
- Implement performant & reliable Mule applications – 27%
- Implement maintainable & modular Mule apps + Maven builds – 25%
- Secure data at rest & in transit – 20%
Master these first, then refine the remaining domains (APIs and monitoring).