The Short Answer
The Salesforce Certified MuleSoft Developer exam has 60 multiple-choice questions plus up to 5 unscored, a 120-minute time limit, a 70% passing score, a US$200 registration fee (US$100 to retake) and no prerequisite. Its questions align to the Spring '24 release (checked in October 2026 against the official exam guide).
It's a code-reading exam. Most objectives end in "and predict outcomes", so expect a Mule XML flow or a DataWeave script and a question about what the payload, a variable or the error looks like afterward. The credential used to be called MuleSoft Developer I, and it's the required prerequisite for MuleSoft Developer II.
Exam Details at a Glance
| Detail | MuleSoft Developer |
|---|---|
| Questions | 60 multiple-choice, plus up to 5 unscored |
| Time limit | 120 minutes |
| Passing score | 70% |
| Registration fee | US$200 (JPY 30,000), plus applicable taxes |
| Retake fee | US$100 (JPY 15,000), plus applicable taxes |
| Prerequisite | None |
| Release alignment | Spring '24 |
| Delivery | Proctored, online or at a testing center |
| References allowed | None |
| Maintenance | The certification's maintenance badge on Trailhead, once a year |
Source: the exam guide for every row, checked in October 2026.
70% of 60 is 42, so you can miss 18 questions and still pass. You get about 1.8 minutes for each of up to 65 questions, which is more than most Salesforce exams allow, and you'll need it: reading a 15-line flow carefully takes longer than reading a two-sentence scenario. For fees and retake rules across every Salesforce exam, see Salesforce certification cost and retake fees.
On the name: the exam guide now says "Salesforce Certified MuleSoft Developer", while the Trailhead credential page still carries the old "Developer I" in its URL. Older prep material also calls it MuleSoft Certified Developer - Level 1 (Mule 4). It's the same exam.
Who the Exam Is For
The exam guide describes someone with experience on basic Mule 4 projects, working with guidance and supervision. That person can take an API through its lifecycle on Anypoint Platform (design, build, deploy, manage, govern), build and debug integrations in Anypoint Studio, connect to databases, files, web services, SaaS apps and JMS queues, write basic DataWeave 2.0 transformations, control event flow, handle errors and process batch records. Typical roles are developer, architect and administrator.
The exclusions matter as much. You aren't expected to build production-ready integrations in a DevOps environment, write modular Maven builds, make apps monitorable, tune for performance and reliability, or secure data at rest and in transit. Those topics belong to MuleSoft Developer II, so a question here won't hinge on them.
The 12 Exam Sections and What They Test
All weights and objectives come from the official outline. No section is above 10%, so you can't pass on two strong topics.
| Section | Weight | About this many questions (of 60) |
|---|---|---|
| Creating Application Networks | 7% | 4 |
| Designing APIs | 8% | 5 |
| Accessing and Modifying Mule Events | 10% | 6 |
| Structuring Mule Applications | 10% | 6 |
| Building API Implementation Interfaces | 7% | 4 |
| Using Connectors | 10% | 6 |
| Processing Records | 10% | 6 |
| Transforming Data | 10% | 6 |
| Routing Events | 8% | 5 |
| Handling Errors | 8% | 5 |
| Debugging and Troubleshooting Mule Applications | 5% | 3 |
| Deploying and Managing APIs and Integrations | 7% | 4 |
The sections fall into four groups.
API-led design (Creating Application Networks, Designing APIs, Building API Implementation Interfaces: 22%)
The concepts: application networks, the system, process and experience API layers, and the Center for Enablement (C4E) operating model. Then RAML: methods, resources, responses, and when a value belongs in a URI parameter (it identifies the resource, as in /orders/{orderId}) versus a query parameter (it filters or pages the result). Then APIkit, which scaffolds flows from a RAML spec. The APIkit error handling reference maps its error types to status codes: APIKIT:BAD_REQUEST to 400, APIKIT:NOT_FOUND to 404, APIKIT:METHOD_NOT_ALLOWED to 405, APIKIT:NOT_ACCEPTABLE to 406 and APIKIT:UNSUPPORTED_MEDIA_TYPE to 415. A "which status does the client get" question usually comes down to this table.
The Mule event (Accessing and Modifying Mule Events, Structuring Mule Applications: 20%)
Know the Mule 4 event exactly: a message with a payload and attributes, plus variables that sit beside the message. Two documented behaviors produce most of the trick questions:
- Target variables leave the payload alone. The target variables page says that when an operation sets a target, it passes the next component the same message it received, and stores its result in the variable instead. The page adds that target variables aren't set when the operation errors.
- Subflows aren't flows. Per Flows and Subflows, a subflow has no event source and no error handling scope of its own, and at build time each Flow Reference to it is replaced by its contents. A question that asks which error handler catches an error raised in a subflow is testing that.
Connectors, records and DataWeave (Using Connectors, Processing Records, Transforming Data: 30%)
The biggest block. Database and File/FTP operations, combining data mid-flow, For Each, batch jobs, the DB listener, persisting data between runs with Object Store, and DataWeave from coercion to modules.
Watch for: the For Each output. The For Each scope page says it "does not modify the current payload. The output payload is the same as the input", while variable changes made inside the loop stay visible after it. So in this flow, the logger after the loop prints the original array, not the last item:
<set-payload value='#[["a", "b", "c"]]' />
<foreach>
<set-payload value="#[upper(payload)]" />
</foreach>
<logger message="#[payload]" />
Batch jobs have their own vocabulary: the Load and Dispatch, Process and On Complete phases, batch steps, and the Batch Aggregator, which per the batch components page sends records in fixed-size groups (size="200") or streams them all (streaming="true").
For DataWeave, keep every snippet you practice on valid DataWeave 2.0: a %dw 2.0 header, an output directive, the --- separator, and as for coercion. Mule 3 syntax such as MEL or #[message.payload] is a wrong answer by definition.
Routing, errors, debugging and deployment (Routing Events, Handling Errors, Debugging, Deploying and Managing: 28%)
Watch for: On Error Continue versus On Error Propagate. The On-Error components page says On Error Propagate runs and then re-throws the error to the containing scope or calling flow, rolling back any transaction its owner handles, while On Error Continue runs and returns its result as if the owner had succeeded, committing the transaction. On-Error components match in order, so the first matching type wins. Pair that with Try scopes, global error handlers and custom error mapping, and you've covered most of the 8%.
The Scatter-Gather page gives two more: routes run in parallel and the output is an object keyed by route index (0, 1, and so on), and if any route fails the router throws MULE:COMPOSITE_ROUTING.
For deployment, the guide says CloudHub, and the management objectives are API proxies and autodiscovery. The autodiscovery overview says it pairs a deployed Mule app with API Manager so the app can download and apply policies, and that the flow must start with an HTTP Listener. Then know which policies do what, starting with client ID enforcement and rate limiting.
What's Changed Since Spring '24
The exam is two and a half years behind the product, so docs and exam don't always use the same words:
- Runtime and tools. The docs now cover Mule runtime 4.13 (October 2026), and Anypoint Code Builder, built on Visual Studio Code, is an alternative IDE. The exam guide still names Anypoint Studio, so practice in Studio.
- Gateway naming. The docs now call Flex Gateway Omni Gateway ("formerly Flex Gateway"). The exam's proxy and autodiscovery objectives are about Mule gateway features in API Manager, so don't let the new name pull you off a question.
- CloudHub versus CloudHub 2.0. Both exist. The exam guide's objective says "Deploy applications to CloudHub", so read deployment questions with that in mind.
A Six-to-Eight-Week Study Plan
- Read the exam guide and score yourself. Rate each of the 40 objectives from 1 to 3. Our guide to using the exam outline to plan your study shows how to turn weights into study hours.
- Take a baseline. Try the 18 free MuleSoft Developer practice questions to see how flow-reading questions are framed and find your weakest section.
- Work the recommended training. The exam guide recommends the Getting Started with Anypoint Platform (MAX150) and Anypoint Platform Development: Fundamentals (DEX401) trailmixes, plus the instructor-led DEX401 course from Trailhead Academy.
- Build one API end to end in Anypoint Studio. Write a small RAML spec with a URI parameter and a query parameter, scaffold it with APIkit, read from a database, transform with DataWeave, loop with For Each, and add a Try scope. Deploy it to CloudHub and pair it with API Manager through autodiscovery.
- Predict, then run. Before each run, write down what you expect the payload, attributes and variables to be. Change one thing (a target variable, an On Error Continue that should be Propagate) and predict again. This is the exam's question type.
- Practice under time. Book the exam when you're steadily above 70% and can say why each wrong option is wrong. Our guide to answering Salesforce scenario questions covers multi-select tactics.
MuleSoft Developer Practice Exam on Certifyforce
Certifyforce has a practice bank written to this exam's 12-section outline and checked against the MuleSoft documentation and Trailhead. It isn't affiliated with Salesforce, and it contains no recalled exam questions or brain dumps.
- 18 free practice questions, spread across all 12 sections by weight, each with the answer, why the other options are wrong, and the page it was checked against. No account needed.
- The MuleSoft Developer study guide: the outline of 40 lessons, one per exam-guide topic, about five hours of reading, with each lesson linked to the practice questions that test it.
- The MuleSoft Developer practice exam: 300 reviewed questions with timed 60-question, 120-minute exams weighted like the real one. The full practice exam and study guide pack is now on sale; see pricing for the options.
Frequently Asked Questions
How many questions are on the MuleSoft Developer exam?
60 multiple-choice questions plus up to 5 unscored ones, in 120 minutes, with a 70% passing score, per the exam guide.
How much does the MuleSoft Developer exam cost?
US$200 (JPY 30,000) plus applicable taxes, and a retake costs US$100 (JPY 15,000), per the exam guide.
Is MuleSoft Developer the same as MuleSoft Developer I?
Yes. Salesforce dropped the "I" from the name; the exam guide now says Salesforce Certified MuleSoft Developer, and it's the required prerequisite for MuleSoft Developer II.
Do I need to know Java or Salesforce to pass?
No prerequisite certification is required, and the outline doesn't test Java or Salesforce administration. It tests Mule 4 flows, DataWeave 2.0, RAML and Anypoint Platform. Hands-on time in Anypoint Studio matters more than any other background.
Should I study in Anypoint Studio or Anypoint Code Builder?
Anypoint Studio. The exam guide names Studio for building, testing and debugging, and the debugging objectives assume its tools. Code Builder is fine for day-to-day work after you pass.
How do I keep the certification?
Complete the MuleSoft Developer maintenance badge on Trailhead once a year. If you miss the due date, the certification expires.