MuleSoft Interview Questions

MuleSoft Interview Questions & Answers One Should Know

Application and data integration has become an integral part of a day to day operations of modern businesses. The demand for data integration tools has grown tremendously due to the ever-growing integrations needs of modern business operations. MuleSoft is a widely used data integration platform that connects a variety of applications and data sources. Moreover, this tool also performs additional functions like analytics and ETL processes. If you are looking to start your career in a top Integration tool like MuleSoft or searching for the MuleSoft interview questions then you are on the right track.

To make your MuleSoft interview preparation process a cakewalk we have created a list of frequently asked MuleSoft interview questions based on the opinions of MuleSoft experts and after long research. If you are a fresher and about to start your career in MuleSoft or an experienced professional willing to upgrade your Mule ESB skills, the following MuleSoft 4 interview questions will surely help you. We assure you that the following questions will definitely help you build confidence in yourself and help you clear the MuleSoft interview.

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Top MuleSoft 4 Interview Questions and Answers:

To simplify the learning path for the learners we have divided this blog into three categories which are as follows:

    1. Basic MuleSoft interview questions
    2. Advanced MuleSoft interview questions
    3. Complex MuleSoft interview questions

Basic MuleSoft interview questions

1) What is MuleSoft?

MuleSoft is a next-generation data integration platform built for solving the data integration needs of modern businesses. It acts as a medium to connect a variety of data sources and applications, and perform ETL processes and analytics. MuleSoft also connects enterprise and SaaS applications in the cloud and traditional data sources.

The MuleSoft Anypoint platform is built around the Mule ESB and Event-driven architecture. This platform developed based on a network of data, devices and applications using APIs. Expanded capabilities of MuleSoft allows easy integrations of new technologies without writing any customized code.

2) What are the various types available in MuleSoft?

In Mule 3 we have three types of variables which are as follows:

  • Flow Variable: This variable is used to assign or to remove variables associated with a message in a current flow.
  • Record Variable: These are the special variable sets and particularly used inside a Batch Job.
  • Session Variable: Session variables help in setting or removing variables tied to a message for a complete lifecycle across multiple flows.

3) State the advantages of MuleSoft?

Following are the advantages arises out of using MuleSoft:

  • Easy to develop integration between legacy systems and SaaS technologies.
  • Increases developers productivity and minimizes the time taken for development.
  • Solves all the issues instantly by managing all the resources from a single interface.
  • Provides and supports tools that enable faster development, testing and implementation of APIs.
  • Anypoint platform is highly flexible and easy to scale as the business grows.

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4) List out the various Exception handlings available in MuleSoft?

Following are the five different types of exception handling Techniques:

  • Global Exception Handling
  • Choice Exception Handling
  • Rollback Exception Handling
  • Catch Exception Handling
  • Default Exception Handling

5) Name the message types in MuleSoft?

The Message types available in MuleSoft are:

  • Bridge message
  • Echo and log message
  • Build a message

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6) What is Mule ESB?

Mule acts as a run time engine for Anypoint Platform, and it is a Java-based enterprise service bus (ESB). This provides an environment where developers can create integration between various applications and allow them to exchange data. The Mule ESB is highly flexible and integrates any existing system despite the variation of technologies used by applications which include Web Services, JMS, HTTP, JDBC, and more. The Mule ESB is a powerful integration platform that can be deployed anywhere, can orchestrate real-time events or batches, and is universally connectable.

7) Explain the features of Mule ESB?

Following are the features of Mule ESB:

  • Message Routing Service
  • Set of Service Container
  • Message Transformation Service
  • Web Service Security

8) What are the different types of primitives used in mediation?

Below mentioned are the different types of primitives used in Mediation:

  • Endpoint Lookup
  • DB lookup
  • Service Invoke
  • Type Filter
  • Data Handler
  • Custom MediationFan-out
  • Message Element Setter
  • Header Setters
  • Fan-in
  • Even Emitter
  • Message Logger
  • BO MapMessage Filter
  • XSLT
  • Sub Flow
  • Stop
  • Fail

9) What are Mule Shared Resources?

The shared resources are defined as common resources that are open to use for the applications under the same domain. The open to using resources are called shared resources. In general, all the shared resources should be defined inside the mule domain project and referred by each project who uses the elements in it.

10) Explain the different types of flow processing strategies?

Below mentioned are the seven different flow processing strategies in MuleSoft:

  • Custom Processing
  • Thread Per Processing
  • Asynchronous Flow Processing
  • Queued Asynchronous Flow Processing
  • Queued Flow Processing
  • Synchronous Flow Processing
  • Non-blocking Flow Processing

11) Define API?

API stands for Application Programming Interface (API), which acts as an intermediary and allows communication between two applications, and eliminates human interaction. APIs provide a communication process where products and services communicate with other products and services.

12) What are the different features of API?

Following are the different features of APIs:

  • Efficiency
  • Customizable
  • Wider reach
  • Data ownership
  • Personalization
  • Time effective
  • Easy integration with GUI
  • Language-independent

13) What is Payload in MuleSoft?

In MuleSoft the Payload acts as a run time variable that stores arrays or objects.

14) What is Mule Message?

Mule Message is defined as data that is processed through an application using one or multiple flows.

15) What are the main parts of Mule 3 messages?

Mule message contains mainly two parts which are as follows:

1) Header: It stores the metadata of a message and this data consists of properties that are useful in providing the essential information about the message.

2) Payload: contains the business data.

16) What are the different flow strategies used in MuleSoft?

Following are the six types of Flow strategies we use in MuleSoft:

  • Custom flow processing
  • Queued flow processing
  • Tread per processing
  • A queued asynchronous flow processing
  • Synchronous flow processing
  • Non-blocking flow processing
  • Asynchronous flow processing

17) What is the correlation ID in MuleSoft?

In MuleSoft a correlation ID is a unique value that is automatically assigned to an event at the start of a flow. The Correlation ID can be taken from a predefined variable #(correlation). This can also be called as a Mule Event or identifier.

18) Name a few widely used ESPs in today’s market?

Following are the widely deployed ESPs in the market:

  • Mule ESB
  • Talend
  • JBoss fuse ESB

19) What is a model layer in Mule?

The model layer is nothing but the first logic layer in MuleSoft. It acts as a runtime environment and hosts services. It defines and monitors the working style of Mule while processing the requests handled by these services.

20) What is the use of Outbound EndPoint in MuleSoft?

Outbound endpoints in Mule soft allows us to execute the following things:

  • Write to file streams
  • Send SOAP messages
  • Send email messages

21) What do you know about a fan-in?

Fan-in within the execution flow acts as a decision point and decides when to start and continue the execution. It receives the messages until the decision point limit is reached.

22) What is the primary use of Fan-out?

The primary use of fan-out is that we can fire the single or multiple outputs using fan-out.

23) What do you know about Mule Expression?

Mule expression is a component through which we can use Java code to perform the process of validation. Mule Expression not only improves efficiency but also increases the time of the validation process.

24) What is Mule Expression Language?

Mule Expression Language gives the developers a standard and consistent way to work with Mule message variables, payloads, and properties. We can modify the activities like filtering and routing by using MEL.

25) What are the expression components present in Mule4?

Well, there are no expression components in Mule4. A message component called “dataweave transform” is used in the place of expression.

26) List various endpoints in Mule ESB?

Different endpoints in Mule ESB are:

  1. HTTP
  2. AJAX
  3. IMAP
  4. JMS
  5. SMTP

27) What is the use of Transient context?

Transient context is used to pass the values among the different mediation primitives present in the current flow.

28) What is the use of shared context?

The shared context is used to iterate the BO in the Aggregation process. It maintains the Aggregation data among the Fan-in and Fan-out primitives.

29) What are the different parts you will find in the message composition?

The three different parts we can find in the message composition are:

  • Properties: Properties is the header part of a message.
  • Payload: Payload is the primary data/message.
  • Multiple name attachments: we can send multiple messages or payloads throughout the event process.

30) What is the use of Correlation context?

Correlation context is used to transfer the values between request flow and response flow.

31) What is a connector?

A connector is software that allows us to connect the mule flow with any external resource. An external source can be an API, database, or Protocol.

32) List various connectors in Mulesoft?

Different types of connectors used in Mulesoft are:

  • Kafka connector
  • Object store connector
  • LDAP connector
  • Netsuite connector
  • CloudHub connector
  • Workday connector
  • Microsoft Dynamics CRM connector
  • Anypoint MQ connector 

33) What is a component?

Components are the main blocks of Mule Applications. These are used to run the business logic over the messages that flow within your applications.

34) List different core components of Mulesoft?

There are five different core components of Mulesoft they are:

  1. HTTP proxy
  2. Simple service pattern
  3. WS proxy
  4. Validator
  5. Bridge 

35) What are the different parts of Mule flow?

There are two parts in a Mule flow they are:

  1. Message Header: Message Header consists of the metadata.
  2. Payload: Payload consists of the original business info/data.

36) List different modules of Mulesoft?

Different modules of Mulesoft are:

  • Amazon Redshift connector.
  • AJAX connector 3.9
  • Amazon Lambda Connector
  • Amazon EC2 Connector 2.5
  • Amazon SNS Connector 4.5
  • Amazon Kinesis Connector

37) What are the various ESB you frequently find in the market?

Even though there are many ESBs available in the market, there are three frequently found ESBs they are:

  1. Mule ESB
  2. JBoss Fuse ESB
  3. Talend

38) What is SOAP?

SOAP is abbreviated as Simple Object Access Protocol, which is used to communicate over the internet. HTTP is extended for XML messaging by SOAP which also offers data transport over web services.

39) How to create a SOAP service?

We can create SOAP service in four steps:

Step1: The first step is to build a Mule project and then arrange the HTTP Listener.

Step2: To save the URI parameter, we have to use the set variable.

Step3: In the third step, consume the SOAP web service.

Step4: Finally, test the SOAP service.

40) What are the components used to consume a SOAP service?

We can use CFX or Web Service Consumer Components to Consume/Access the SOAP service within the Mule flow.

41) Define web service?

Web service is a program through which various devices can communicate over a network. Every web service acts as a client and server. A web service can have multiple clients for one server.

42) What are the features we have to consider before selecting an ESB?

Before selecting an ESB, we have to consider these six features:

  • Maintainability
  • Flexibility
  • Community
  • Usability
  • Cost
  • Reliability

43) What is RAML?

RAML is abbreviated as RESTful API Modeling Language. RAML lets the client know what services are provided by the organization and how the operations are summoned.

RAML is the same as a WSDL; RAML also contains HTTP methods, URI parameters and queries, endpoint URL, and request/response schemas.

44) Differentiate JMS and ESB?

JMS: JMS offers the capability of messaging and communication facilities between applications and modules.

ESB: ESB offers interfaces and middleware that can connect to their applications without any code.

45) What are the full forms of SMO and SDO?

SMO: SMO is abbreviated as Service Model Object.

SDO: SDO is abbreviated as Service Data Object.

46) What is the service invoke?

Service invoke is a process of creating a service either for response or request flows. The service may be a response, request, both, or one-way implementation.

47) What is the purpose of CallOut?

The one and essential purpose of CallOut is to request any service and receive a message and operation within a flow. There is always a CallOut node that is present within the medium flow for connected destination operation.

48) What is Fileage?

Fileage is a time of waiting for an endpoint before starting a new process. For example, assure that the Fileage is 120000, then the endpoint must wait for two minutes to start a new process.

49) List the various available resources utilized for modularizing configuration?

The four essential available resources utilized for modularizing configuration are:

  • Inherited configuration
  • Independent configuration
  • Heterogeneous configuration
  • Imported configuration

50) What are the primitives used to implement a loop in mediation?

In mediation, we can Implement a loop by using Fan-out and Fan-in primitives.

51) When to set a pooling frequency?

Whenever you want to read a new file content with new inbound endpoints, then we have to set a pooling frequency.

52) What is streaming?

Streaming is the process of reading the data from documents, records, and files. If we are streaming, there is no need to read the entire document, record, or file. We can just get the required data.

53) What is a CloudHub?

CloudHub is an iPaaS(Integrated Platform as a Service) through which we can quickly deploy cross-cloud applications. CloudHub is used to combine on-premise applications and create new APIs.

54) List different components of CloudHub?

There are two different components in CloudHub they are:

  1. Worker cloud
  2. Platform services 

55) What are filters?

Filters are the things that decide which messages to pass or process. Filters allow messages to pass or process only when the message meets all the requirements.

56) What is a future by using which we can change the runtime modifications by mediation primitive?

Promotable properties in ESB are used to change the runtime modifications by mediation primitive.

57) What is fullform of UMO?

UMO is abbreviated as Universal Message Object. The components of UMO were once called Service components.

58) Write syntax to configure FTP handler?

The following is the syntax to configure the FTP handler:



59) What is a Mule?

Mule is nothing but a framework provided by Mulesoft. Even though the Mule is a Java-based platform, it still can broker communications among other platforms like .NET by using sockets and services.

60) How do you resolve it if Mule doesn’t start?

One of the main reasons and common mistakes by users is mistakenly setting up the mule variables. If Mule is not starting, check these following variables:

  1. JAVA_HOME: This should be the exact location of the JDK file.
  2. PATH: This must contain both MULE_HOMEbin and JAVA_HOMEbin within the path.
  3. MULE_HOME: This must be the precise location of an installed mule.


Hope you have found the useful information in this Mule ESB interview questions blog. We update this blog on a regular basis, with the latest MuleSoft interview questions and their respective answers, so stay tuned to this blog for fresh and latest MuleSoft interview questions. Thanks for reading! Happy Learning!

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