Top Salesforce Developer Interview Questions and Answers: Core Architecture, Apex & Modern Best Practices

In plain words: A Salesforce Developer interview evaluates more than just your ability to write syntax. Hiring managers look for developers who understand multi-tenant Governor Limits, follow clean architecture patterns (like trigger frameworks and LWC reactivity), know when to use declarative Flow vs. programmatic Apex, and design secure, bulkified enterprise solutions.

Technical interviews for Salesforce Developer positions have shifted significantly in recent years. Today's hiring panels expect candidates to demonstrate a solid grasp of modern architecture—including modern CI/CD with the Salesforce CLI, secure data queries with WITH USER_MODE, the retirement of legacy Workflow Rules in favor of Flow and Apex, and asynchronous processing scale. Below is a curated breakdown of the top technical questions, complete with architect-grade answers and code examples.

1. What is the Difference Between an Apex Trigger and Record-Triggered Flow?

Q: How do you choose between declarative Flow automation and Apex Triggers?

While legacy Workflow Rules and Process Builder have been retired by Salesforce, Record-Triggered Flows and Apex Triggers serve complementary roles on the modern platform:

• Apex Triggers: Programmatic handlers capable of handling high-throughput bulk transactions, complex collection transformations, fine-grained recursion control, custom cryptography, and high-frequency external integrations.
• Record-Triggered Flows: Low-code declarative automations ideal for straightforward same-record field updates (Fast Field Updates) and standard cross-object operations maintained by admins and business analysts.

360 Developer Decision Matrix: Apex vs. Flow:

• Complex Logic / Deep Maps: Choose Apex Trigger with an established handler framework.
• Standard Same-Record Updates: Choose Record-Triggered Flow (Before-Save) for rapid configuration.
• High Data Volume (Bulk Ingestion): Choose Apex to prevent CPU timeouts and maintain strict query control.
• Cross-Department Maintainability: Prefer Flow when business teams require visual maintenance.

2. What are Governor Limits and How Do You Design for Them?

Q: Explain Salesforce Governor Limits and how you avoid hitting them.

Because Salesforce operates as a multi-tenant cloud where multiple customers share computing hardware, Governor Limits are runtime constraints enforced by the Apex engine to prevent runaway processes from monopolizing resources.

• Synchronous SOQL Limit: 100 queries per transaction.
• Synchronous DML Limit: 150 statements (affecting up to 10,000 total records).
• Maximum CPU Timeout: 10,000 ms (synchronous) / 60,000 ms (asynchronous).
• Heap Size Limit: 6 MB (synchronous) / 12 MB (asynchronous).

Interview Trap: Never put SOQL queries or DML statements inside a loop. This is the fastest way to hit the 100-query or 150-DML limit during bulk data processing. Always collect records in a List or Map and execute a single database operation outside the loop.

3. How Do You Optimize SOQL Queries for Enterprise Scale?

Q: What makes a SOQL query "selective" and how do you ensure fast query execution?

When an object holds over 200,000 records (Large Data Volume), non-selective SOQL queries result in full table scans that degrade performance and cause CPU timeouts:

• Use Indexed Fields in Filters: Filter records using standard indexed fields (Id, Name, OwnerId, CreatedDate) or custom fields marked as External ID or Unique.
• Avoid Negative Filter Operators: Operators like !=, NOT LIKE, and EXCLUDES cannot use standard b-tree indexes.
• Enforce User Mode Security: Always append WITH USER_MODE to queries to automatically enforce object and Field-Level Security (FLS).

// Selective, secure query following modern Salesforce standards
List<Contact> activeContacts = [
    SELECT Id, FirstName, LastName, Email 
    FROM Contact 
    WHERE AccountId = :targetAccountId 
      AND IsActive__c = TRUE 
    WITH USER_MODE 
    LIMIT 200
];

4. Compare Relationship Types: Lookup, Master-Detail & Many-to-Many

Q: What are the key architectural differences between Lookup and Master-Detail relationships?

Feature	Lookup Relationship	Master-Detail Relationship
Record Dependency	Loose link; child can exist without parent	Tight coupling; child is deleted if parent is deleted (Cascade Delete)
Security & Ownership	Child has its own Owner field and sharing rules	Child inherits Owner and security settings directly from the Master record
Roll-Up Summary Fields	Not supported natively (requires Flow or Apex)	Supported natively on the Master object (SUM, COUNT, MIN, MAX)
Relationship Limit	Up to 40 lookups per custom object	Maximum 2 master-detail relationships per custom object

5. How Do You Structure Modern Exception Handling and Logging in Apex?

Q: How should enterprise Apex code handle exceptions and rollbacks?

Standard try-catch blocks that merely debug errors to the system log fail silently in production. Enterprise architectures rely on dedicated logging frameworks and database savepoints:

Production-Ready Pattern: Transaction Rollbacks with Database Savepoints

Savepoint sp = Database.setSavepoint();

try {
    // Perform critical database operations
    update as user primaryAccounts;
    insert as user relatedTasks;
} catch (DmlException dmlEx) {
    // Roll back changes to prevent partial data corruption
    Database.rollback(sp);
    
    // Publish an error log record or Platform Event for admin alerting
    ErrorLoggerService.logException(dmlEx, 'AccountProcessor', 'updateAccounts');
    throw new CustomApplicationException('Operation failed. Rolled back all changes: ' + dmlEx.getMessage());
}

6. How Do You Manage Deployments and CI/CD Pipelines in Modern Salesforce?

Q: What tools and methodologies do you use for source-driven development?

• Salesforce CLI (sf): Drives automated deployments, scratch org provisioning, and metadata synchronization.
• Source-Driven Git Branching: Source of truth lives in Git repositories rather than directly in development sandboxes.
• Automated CI/CD Validation: Every pull request triggers automated unit test runs (--test-level RunLocalTests) and static code analysis (PMD / Salesforce Code Analyzer) before merging into staging and production branches.

7. Core Developer Best Practices & Key Rules

Core Rule: Bulkify all Apex code to handle 200+ records, isolate unit tests using @testSetup without SeeAllData=true, enforce user-mode database operations with WITH USER_MODE, and structure triggers with a single handler per object.

• Use the Modern Assert Class: Replace deprecated System.assertEquals() with Assert.areEqual(expected, actual, message) in all unit tests.
• Adopt Asynchronous Frameworks: Choose Queueable Apex for sequential job chaining and complex object parameters, and Batch Apex for processing millions of historical records.
• Enforce Strict FLS and CRUD: Always use WITH USER_MODE on SOQL and as user on DML statements to ensure custom code respects permission sets and profile restrictions.

Summary

Acing a Salesforce developer interview requires articulating both the "how" and the "why" behind your technical decisions. By demonstrating an in-depth understanding of Governor Limit management, secure SOQL patterns, trigger handler frameworks, and modern source-driven CI/CD practices, you can showcase true enterprise engineering capability and stand out to hiring managers.