Quick definition
Apex is Salesforce’s strongly typed, object-oriented programming language that runs on the Salesforce platform. It lets developers write custom business logic—triggers, classes, batch jobs, schedulable processes, web service endpoints, and integrations—executed on the Salesforce server.
Core capabilities
Use Apex when you need:
- Complex transactional logic that goes beyond declarative limits
- Fine-grained control over order of execution, error handling, and rollbacks
- Custom REST/SOAP APIs, callouts to external systems, or streaming/push topics
- Asynchronous processing: Batch Apex, Queueable, Future methods, or Scheduled Apex
- Unit tested, version-controlled code with sophisticated data transformations
Example Apex uses
Typical scenarios where Apex is required:
- Complex recalculation of related records that must be bulkified and efficient
- Custom authentication flows or OAuth integrations
- Large data volume processing requiring Batch Apex
- Transactional callouts (call external service and then commit or rollback)
Salesforce Flow — When to prefer declarative automation
Flows (Record-Triggered Flows, Screen Flows, Scheduled Flows) are Salesforce’s low-code automation tool. Flows are ideal for admins and developers for many automation tasks because they:
- Are faster to build and maintain for standard business logic
- Provide a visual, auditable representation of automation
- Support most CRUD operations, simple branching, and collections without code
- Can be invoked from Process Builder, buttons, or other flows
Use Flow when
- The logic is straightforward (field updates, creating related records, simple loops)
- You need a UI-driven solution (Screen Flows for guided user input)
- Administrators should be able to maintain the automation
- You want faster delivery and easier audits for compliance
Apex vs Flow — Decision checklist
When choosing between Apex and Flow, consider these practical points:
- Complexity: If the logic involves complicated algorithms, non-trivial data transformations, or branching that becomes unreadable in Flow, favor Apex.
- Bulkification & Performance: Apex gives explicit control to handle large volumes efficiently (use collections, limits management). Flows have improved bulk handling but can still be limited in very high-volume scenarios.
- External Integrations: For synchronous callouts in transactional scenarios, or advanced integration patterns, Apex is required.
- Asynchrony: For Batch processing, complex queueable chaining, or advanced scheduled tasks, use Apex.
- Maintainability: If admins must update logic frequently without developer changes, prefer Flow if it fits the requirements.
- Testing & CI/CD: Apex has mature unit testing, code coverage requirements, and fits well into CI/CD pipelines. Flows have limited unit-test support—rely more on integration testing and monitoring.
- Governance & Security: Apex provides finer control over transactions, exception handling, and custom permission enforcement. Use it when these are critical.
Best practices when using Apex
- Always bulkify triggers and use trigger frameworks or handler patterns
- Keep logic out of triggers — delegate to handler classes
- Use asynchronous Apex for long-running or large-volume operations
- Write robust unit tests covering positive and negative paths; mock callouts where needed
- Handle governor limits: use efficient SOQL, avoid queries/ DML inside loops, and cache results
- Document why Apex was chosen over Flow (for future maintainers)
Quick decision table (summary)
If you prefer a compact rule-of-thumb:
Use Flow: for straightforward CRUD, admin-maintainable logic, and screen-based interactions.
Use Apex: for complex logic, external integrations, massive volume processing, or when precise control over transactions and testing is required.
Closing note
Salesforce’s roadmap often enhances Flow capabilities, so always re-evaluate non-functional requirements before choosing Apex. When in doubt, prototype in Flow first — if you hit limitations, implement the robust solution in Apex and document the reasons.