Module 18 — Interview Coding Scenarios
This is the final technical module: the goal is not to make you memorize all Mule XML, but to make sure you can sketch credible code and explain what every part is doing.
The most likely things they may ask you to write are:
1. A basic Mule flow
2. DataWeave transformation
3. SOQL query
4. Choice routing
5. Salesforce Upsert
6. Error handling
7. A small MUnit test
8. A complete mini-integration
The key interview rule is:
If you forget exact Mule XML syntax, write structurally correct pseudocode/XML and explain the architecture clearly.
A good interviewer should care much more that you understand what belongs where than whether you remember every namespace attribute.
18.1codeScenario 1 — Build a simple Mule API flowPrompt:18.2What to say while codingDon't silently type.18.3codeScenario 2 — DataWeave mappingPrompt:18.4codeScenario 3 — Map an arrayPrompt:18.5codeScenario 4 — Filter and mapPrompt:18.6codeScenario 5 — Handle missing valuePrompt:18.7codeScenario 6 — Type conversionInput:18.8codeScenario 7 — Conditional business valuePrompt:18.9codeScenario 8 — SOQL by External IDPrompt:18.10codeScenario 9 — Contact plus AccountPrompt:18.11codeScenario 10 — Account with ContactsPrompt:18.12codeScenario 11 — Incremental SOQLPrompt:18.13codeScenario 12 — Choice routingPrompt:18.14codeScenario 13 — More than two Choice branchesBut if CREATE and UPDATE can both use:18.15codeScenario 14 — Raise custom business errorPrompt:18.16codeScenario 15 — On Error ContinuePrompt:18.17codeScenario 16 — On Error PropagatePrompt:18.18codeScenario 17 — Error-to-HTTP mappingA clean conceptual design:18.19codeScenario 18 — RetryPrompt:18.20Scenario 19 — Don't wrap too much in retryAvoid:18.21codeScenario 20 — Parallel callsPrompt:18.22codeScenario 21 — Parallel processing of arrayPrompt:18.23codeScenario 22 — For Each or DataWeave?Prompt:18.24Scenario 23 — Account then ContactsPrompt:18.25Scenario 24 — What if Contacts partially fail?Say:18.26Scenario 25 — APIKitPrompt:18.27codeScenario 26 — MUnit happy-path testPrompt:18.28Scenario 27 — MUnit negative testPrompt:18.29Scenario 28 — MUnit connector failureMock:18.30codeScenario 29 — Idempotency test in TypeScriptIf they shift from MUnit to your stronger area:18.31codeScenario 30 — Async integration testEndpoint:18.32Scenario 31 — Bulk designPrompt:18.33codeScenario 32 — A DataWeave challenge likely to appearInput:18.34codeAnother DataWeave challenge — group by customerInput:18.35codeWhat DataWeave syntax should you memorize?These are enough for your interview:18.36codeWhat SOQL should you memorize?These three:18.37What Mule components should you be able to name without thinking?Memorize this list:18.38●Component selection drill18.39Q&AThe coding-interview trap: overengineeringPrompt:18.40Another trap: underengineeringConversely:18.41Another trap: exact syntax panicIf you forget whether the attribute is:18.42codeYou are not expected to memorize generated XML namespacesMule XML often includes:18.43What to say if you've never implemented that exact Mule componentFor example they ask:18.44What to say if they ask you to write code from memoryYou can frame it naturally:18.45codeThe mini-project you should be able to build from memoryIf you have time before the interview, practice exactly this one application:18.46codeThe corresponding DataWeaveAccount:18.47The corresponding MUnit storySay:18.48codeThe corresponding external testThat's where you can leverage your strongest coding skill if the discussion moves toward test automation.18.49Q&AFinal interview drill: one-minute answersIf they ask:18.50codeThe five snippets I would memorizeEverything else can be reconstructed around those.•cheat sheetModule 18 Cheat SheetYou do not need to impersonate someone who has spent five years hand-writing Mule XML.