MuleSoft Certified Developer - Level 1 (Mule 4) DELTA


MuleSoft Certified Developer - Level 1 (Mule 4)A MuleSoft Certified Developer – Level 1 (Mule 4) should be able to successfully work on basic Mule 4 projects with guidance and supervision. The MCD – Level 1 (Mule 4) DELTA exam validates that a certified MuleSoft Certified Developer – Integration and API Associate (Mule 3.8+) has the required knowledge and skills to design, build, test and debug, deploy, and manage basic Mule 4 APIs and integrations. S/he should be able to:

  • Use MuleSoft-hosted Anypoint Platform to take a basic API through all the steps of its lifecycle: design, build, deploy, manage, and govern.
  • Use Anypoint Studio to build, test, and debug basic Mule 4 integrations and API implementations.
  • Use Mule 4 connectors to connect to a range of resources including databases, files, web services, SaaS applications, and JMS queues.
  • Perform basic data transformations using DataWeave 2.
  • Use Mule 4 event processors to control event flow, handle errors, and process batch records.

A downloadable datasheet for the exam can be found here.


  • Format: Multiple-choice, closed book, proctored online or in a testing center
  • Length: 35 questions
  • Duration: 75 minutes
  • Pass score: 70%
  • Language: English

The exam can be taken a maximum of 2 times, with a 24 hour wait between attempts. After an unsuccessful second attempt, the candidate can only take the full MCD – Level 1 exam.


The exam can be purchased with one of the following. Each includes a coupon for one free retake.

Additional retakes (attempts 3 to 5) are $125 or 0.5 FTC and do not come with a free retake.

Note: This exam requires a previous MCD - Integration and API Associate (Mule 3.8+) certification.


The certification expires two years from the date of passing.


The following resources are available to assist in a candidate’s preparation:

  • Instructor-led training: Anypoint Platform Development: Mule 4 for Mule 3 Users
    • Recommended as the most effective and efficient method of preparation
    • 3-day class
    • Private and public classes available
    • Onsite and online classes available
    • Includes a certification voucher for this exam
  • Self-study training: MuleSoft.U Mule 4 for Mule 3 Users
    • 30+ step-by-step exercises to teach you the basics
    • All content available instantly to be completed at any time and pace
    • Supported by the peer-to-peer MuleSoft training forum
    • Does NOT include a voucher for this exam
  • Self-assessment quiz
    • 5+ multiple-choice questions for each knowledge section of the exam
    • Identifies strengths and weaknesses
    • Comparable difficulty to the proctored exam
  • Do-it-yourself exercises
    • 10+ DIY exercises to get experience with and apply the knowledge required for the certification
    • Starting code and solutions provided
    • Can be completed in any order


The exam validates that the candidate can perform the following tasks.

Note: DEV:443 is the acronym for the instructor-led or self-study version of the Anypoint Platform Development: Mule 4 for Mule 3 Users course. DEV:DIY4 is the acronym for the MCD - Level 1 / Development Fundamentals (Mule 4) Self-Assessment Quiz & DIY Exercises materials.

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  • Describe the Mule event data structure
  • Use transformers to set event payloads, attributes, and variables
  • Write DataWeave expressions to access and modify event payloads, attributes, and variables
  • Enrich Mule events using target parameters
  • Parameterize an application using property placeholders
  • Define and reuse global configurations in an application
  • Break an application into multiple flows using private flows, subflows, and the Flow Reference component
  • Specify what data (payload, attributes, variables) is persisted between flows when a Flow Reference is used
  • Specify what data (payload, attributes, variables) is persisted between flows when a Mule event crosses a connection boundary
  • Specify what data (payload, attributes, variables) exists in a flow before and after a call in the middle of a flow to an external resource
  • Manually create a RESTful interface for a Mule application
  • Generate a REST Connector from a RAML specification
  • Describe the features and benefits of APIkit
  • Use APIkit to create implementation flows from a RAML file
  • Describe how requests are routed through flows generated by APIkit
  • Use the Choice router to route events based on conditional logic
  • Use the Scatter-Gather router to multicast events
  • Validate data using the Validation module
  • Describe the default error handling in a Mule application
  • Define a custom global default error handler for an application and identify in what situations it will be used
  • Compare and contrast how the On Error Continue and On Error Propagate scopes work
  • Create one or more error handlers for a flow
  • Use the Try scope to specify error handlers for one or more event processors
  • Describe the data structure of the Mule Error object
  • Map errors to custom application errors
  • Write DataWeave scripts to convert JSON, XML, and Java data structures to different data structures and data types
  • Use DataWeave functions
  • Define and use DataWeave variables, functions, and modules
  • Define and use custom data types
  • Apply correct DataWeave syntax to coerce data types
  • Apply correct DataWeave syntax to format strings, numbers, and dates
  • Call Mule flows from a DataWeave script
  • Retrieve data from a Database using the Database connector
  • Create parameterized SQL queries for the Database connector
  • Retrieve data from a REST service using HTTP Request or a REST Connector
  • Use a Web Service Consumer connector to consume SOAP web services
  • Use the Transform Message component to pass arguments to a SOAP web service
  • List, read, and write local files using the File connector
  • List, read, and write remote files using the FTP connector
  • Use the JMS connector to publish and listen for JMS messages
  • List and compare and contrast the methods for processing individual records in a collection
  • Explain how Mule events are processed by the For Each scope
  • Use the For Each scope to process records
  • Explain how Mule events are processed by the Batch Job scope
  • Use a Batch Job with Batch Steps and a Batch Aggregator to process records
  • Use the Scheduler component to trigger a flow
  • Use connector listeners to trigger flows
  • Describe the features, benefits, and process to use watermarking
  • Describe the features, benefits, and process to use automatic watermarking vs. manual watermarking
  • Use connectors with automatic watermarking capabilities
  • Persist data between flow executions using the Object Store
  • Use breakpoints to inspect a Mule event during runtime
  • Install missing Maven dependencies
  • Read and decipher Mule log error messages
  • DEV:DIY4 Exercise 6-1 and Walkthrough
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  • DEV:DIY4 all exercises
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  • Package Mule applications for deployment
  • Deploy applications to CloudHub
  • Use CloudHub properties to ensure deployment success
  • Create and deploy API proxies
  • Connect an API implementation to API Manager using autodiscovery
  • Use policies, including client ID enforcement, to secure an API
  • Create SLA tiers and apply SLA based policies

Delivery methods

The exam is administered via the Kryterion Webassessor testing platform. The exam can be taken in-person at a testing center or online using a web camera.

In-person at a Kryterion Testing Center:

Online using the Kryterion Webassessor testing platform:

  • Requires a webcam - a laptop webcam can be used, an external camera is not required
  • Requires internet connectivity with 1 Mbps upload, 1 Mbps download, jitter <50ms, ping <200ms
  • Check your internet speed and reliability
    • Note: Some candidates are expelled from the exam for an unstable connection even after checking reliability with the tool. If you think your connection could potentially be unreliable, we strongly recommend scheduling your exam at a test center.
  • Online instructions
  • Test-taker guide


To register for the exam:

  • Go to Webassessor.
  • Log in. If you do not have an existing profile, please create one. Do not create multiple accounts.
  • Click Exam Catalog.
  • Select the MuleSoft Certified Developer – Level 1 (Mule 4) DELTA exam. Click the "+" to expand your test modality options.
  • Select either the Online Proctoring Option or the Kryterion Test Center option.
  • On the payment screen, select to pay by credit card or enter a voucher/coupon code.

Note: A fee applies if an exam is cancelled or rescheduled within 72 hours of its scheduled time, even if the exam was purchased with a voucher.

More information

For more information, visit the Certification Help Center.

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