100+ Salesforce Apex Interview Questions to Master in 2026

Salesforce Apex continues to be one of the most in-demand skills for developers in 2026. With Salesforce expanding across industry clouds, AI integrations, Data Cloud, and automation-first development, companies expect developers to have not just coding knowledge but a deep understanding of Apex best practices, governor limits, integrations, and enterprise-scale architecture.

Whether you’re preparing for a new job, upgrading skills, or building confidence for technical rounds, mastering the right Apex interview questions can make all the difference.

In this blog, we break down 100+ Apex interview questions into three practical categories Low, Mid, and Hard levels, helping you prepare strategically.

1. Low-Level Salesforce Apex Interview Questions (Beginners)

These questions test basic syntax, fundamentals, object model understanding, and simple Apex concepts. Perfect for freshers or those with 0–1 year of experience.

A. Apex Basics & Syntax

1. What is Apex in Salesforce?
2. How is Apex different from Java?
3. What are different types of Apex collections?
4. What is an sObject in Apex?
5. Explain the difference between a class and an object.
6. What is the default access modifier in Apex?
7. What is the use of the “with sharing” keyword?
8. What is SOQL?
9. What is SOSL?
10. When do you use DML in Apex?

B. Triggers

11. What is a trigger?
12. Types of triggers in Salesforce.
13. Before vs After triggers.
14. What is Trigger.new and Trigger.old?
15. What is recursion in triggers?
16. How to avoid trigger recursion?
17. Can we call a future method from a trigger?
18. What is a trigger context variable?
19. Why should we use a trigger handler class?
20. Order of execution in Salesforce.

C. Collections, Loops & Variables

21. List vs Set vs Map differences.
22. How to iterate through a map?
23. Can collections store different types of data?
24. What is a static variable?
25. What is final keyword in Apex?
26. What is the difference between a for-each loop and traditional for loop?
27. What is governor limits?
28. Why do we need bulkification?
29. How many records can a SOQL query return?
30. What is NullPointerException and how to avoid it?

D. DML

31. What are DML operations?
32. What is the difference between insert and upsert?
33. What is Database.insert vs insert?
34. How to handle DML exceptions?
35. What is SavePoint and Rollback?
36. Can we perform DML inside a loop?
37. What happens if DML fails?
38. What is partial DML?
39. Why should we avoid too many DML operations?
40. What is the limit for DML calls in one transaction?

2. Mid-Level Salesforce Apex Interview Questions (Experienced 1–3 Years)

These questions target real-world development, scalable code, integration logic, advanced SOQL, and asynchronous processing.

A. Advanced SOQL & SOSL

41. What is a relationship query in SOQL?
42. What are parent-to-child queries?
43. What are child-to-parent queries?
44. What is a semi-join and anti-join in SOQL?
45. What is the use of Aggregate functions in SOQL?
46. What is a subquery in SOQL?
47. What are polymorphic relationships in Salesforce?
48. How to avoid SOQL injection?
49. Why use LIMIT and OFFSET?
50. Explain Database.Query() usage.

B. Apex Best Practices

51. Explain Apex bulkification with examples.
52. What are Apex design patterns?
53. What is Service Layer Architecture in Apex?
54. Why should we use a trigger framework?
55. What is a singleton class?
56. Difference between public, private, global, and protected.
57. How to write reusable code in Apex?
58. What is platform cache?
59. When to use custom metadata vs custom settings?
60. Why do we need Apex test classes?

C. Integration & API Concepts

61. What is a callout in Apex?
62. Difference between REST and SOAP callouts.
63. What are custom Apex REST endpoints?
64. What is HttpRequest and HttpResponse class?
65. What is the @future(callout=true) annotation?
66. How to handle API timeouts?
67. What is integration retry logic?
68. Explain Named Credentials.
69. What is continuation class used for?
70. How to handle JSON serialization and deserialization?

D. Asynchronous Apex

71. What is a future method?
72. What is batch Apex?
73. Batch Apex execution flow.
74. What is scheduled Apex?
75. Difference between queueable and batch Apex.
76. What is the limit of queueable jobs?
77. Can we chain queueable jobs?
78. When to use @future over queueable?
79. Can batch class call another batch class?
80. What is Database.Stateful?

E. Error Handling & Debugging

81. How to use try-catch-finally?
82. What is the purpose of custom exceptions?
83. How to log errors using Platform Events?
84. What is the system.debug limit?
85. How to test callouts in test classes?

3. Hard-Level Salesforce Apex Interview Questions (Advanced 3+ Years, Architect-Level)

These questions evaluate architecture, multi-org complexity, governor limit challenges, async orchestration, security, and enterprise integrations.

A. Enterprise Architecture & Design

86. Explain Apex Enterprise Patterns in detail.
87. What is the Unit of Work pattern?
88. How to design a scalable trigger framework?
89. How to decouple business logic from triggers?
90. What is dependency injection in Apex?
91. How to handle multi-object transactional logic?
92. What are the best practices for handling bulk updates (10K+ records)?
93. How to design for high data volume (HDV)?
94. How to avoid locking issues (Row Locks)?
95. How to optimize code for large-scale automations?

B. Performance Optimization

96. How to reduce SOQL queries in complex logic?
97. How to handle recursive Apex in real-time systems?
98. How platform events help improve performance?
99. What is the difference between Platform Events, Change Data Capture, and Pub/Sub API?
100. How to optimize API callouts in bulk operations?
101. How to design asynchronous chains in Salesforce?
102. How to decide between batch, queueable, and scheduled Apex?
103. How to prevent race conditions in async Apex?
104. How to handle spikes in event-driven architecture?
105. What are heap size governor limits and how do you optimize it?

C. Security, Compliance & Testing

106. How to enforce FLS and CRUD in Apex?
107. Difference between WITH SECURITY_ENFORCED and stripInaccessible.
108. How do you write a secure REST API?
109. What is Apex managed sharing?
110. How to handle user-sharing model differences in code?
111. Explain test isolation and parallel test execution.
112. How to test async operations?
113. How to use Test.startTest and Test.stopTest?
114. What is mocking in Apex test classes?
115. How to reach 90–100% code coverage with quality?

D. Real-Time Scenarios (Highly Asked in 2026)

116. How to handle automation conflicts (Flows + Apex)?
117. When to replace Flow with Apex?
118. How to handle Data Cloud-triggered events in Apex?
119. How Apex works with Salesforce GenAI (Einstein 1)?
120. How to debug Apex in a multi-cloud setup?
121. How to handle large file processing using Apex + AWS/Azure?
122. How to prevent hitting API limits in integrations?
123. How to build a retry mechanism for failed transactions?
124. How to handle partial success logic in bulk operations?
125. How to implement a custom queue management system using Apex?

Conclusion

Mastering Salesforce Apex in 2026 requires more than just knowing syntax—it demands expertise in multi-object logic, asynchronous architecture, integration scalability, and designing high-performance enterprise systems. The 100+ interview questions above are tailored to match the latest trends in Salesforce development, such as AI-driven automation, Data Cloud integrations, and performance-first architectures.