Start with Flow when the automation maps clearly to supported point-and-click elements; choose Apex when the requirement needs code-level control or logic that Flow cannot express well. Neither record count nor a general impression of complexity decides the question on its own. Evaluate the full transaction, security model, existing automation, maintainability, and the target org’s edition and API version.
When should you use Flow instead of Apex?
Use Flow when you can describe the work as a clear sequence of decisions and record operations, and the team can build and maintain that sequence in Flow Builder. Salesforce describes Flow Builder as a point-and-click tool for automating business processes. Flows can work across multiple objects and provide screens that guide users through a process. Those capabilities make Flow a strong starting point for record-centered automation and guided experiences.
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Use Apex when a specific requirement needs code-level control or cannot be expressed well with the supported declarative features. That is a use-case decision, not a general claim that Apex is always better for complex automation. Salesforce’s automation guidance points to a feature comparison and an architect decision guide for evaluating individual use cases; check those resources against the feature you need before committing to an implementation. Salesforce Automation Best Practice Guide
Compare the requirements, not the labels
| Question | Flow is a natural fit when… | Apex is a natural fit when… |
|---|---|---|
| How is the process expressed? | It maps clearly to supported Flow elements and can be understood as a declarative sequence of decisions and record operations. | The required logic or control does not fit well in the available declarative features. |
| Who or what is the process for? | It is record-centered, spans objects, or needs screens to guide users. | The requirement calls for programmatic behavior rather than a process well represented by those Flow capabilities. |
| What else runs in the save transaction? | The combined Flow, Apex, and other automation fit within the shared transaction limits and save behavior is understood. | A code implementation is needed, but it still must fit the transaction’s shared limits and coexist safely with other automation. |
| Can the team support it? | The declarative design will be readable and maintainable by the team responsible for it. | The team can develop, review, deploy, and operate the required code-level logic. |
This comparison is a starting point rather than a replacement for checking org-specific security, enabled features, volume, and existing automation. Salesforce’s published guidance recommends choosing an automation tool according to the use case, rather than treating one tool as universally preferable. Salesforce Automation Best Practice Guide
Account for shared transaction limits
Flow and Apex do not get separate per-transaction budgets when they run in the same transaction. Salesforce states that Apex per-transaction limits govern Flow, and autolaunched flows share the transaction in which they run. If a governor limit is exceeded, the transaction is rolled back—even when a Flow element has a fault connector. Assess the whole transaction, including Apex, Flow, and other automation launched by it, rather than estimating each component in isolation. Salesforce Per-Transaction Flow Limits
Salesforce’s documented per-transaction limits include the following values. They are platform limits, not performance targets or evidence that a design will perform well up to the ceiling.
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| Documented per-transaction limit | Salesforce value |
|---|---|
| SOQL queries | 100 |
| Records retrieved by SOQL queries | 50,000 |
| DML statements | 150 |
| Records processed as a result of DML | 10,000 |
| Salesforce-server CPU time | 10,000 milliseconds |
These are limits listed in Salesforce Help’s Per-Transaction Flow Limits. Because the budget is shared, a Flow design that looks small by itself can still contribute to a limit breach when other automation runs in the same transaction.
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsMap automation order before mixing tools
When multiple automations change the same record, document which record-triggered Flows, Apex triggers, and legacy automation can run, and how their updates interact. Do not assume a particular order for multiple Apex triggers in the same trigger group: Salesforce says that order is not guaranteed. Salesforce also documents that a workflow field update does not re-fire further rules, Flows, or Apex triggers. These behaviors make a save-sequence map important for avoiding unexpected results, data integrity issues, and loops. Salesforce process-order reminders
Check org edition, Flow type, and API version
Flow limits are not a single org-wide number that can safely be copied from an older article or another Salesforce org. Salesforce’s general Flow limits vary by edition and Flow type, and some details depend on API version. Confirm the current applicable limit for the specific org, Flow type, and API version before finalizing a design. Salesforce General Flow Limits
One example of an API-version-specific value is total heap size per Flow interview: Salesforce lists 215 MB for API version 61.0 and later, compared with 750 MB in API version 60.0 and earlier. This is a Flow interview-size limit; it should not be confused with Apex governor heap as reported in debug logs. Consult the current limits reference for the org’s applicable values rather than extrapolating from this example. Salesforce General Flow Limits
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A practical decision process
- Write down the behavior. Describe the decisions, records changed, user interaction, security needs, and required outcomes without choosing a tool first.
- Prototype the declarative fit. Check whether supported Flow elements can express the behavior clearly. If it is record-centered or needs a guided screen, assess Flow Builder as the first option.
- Identify any unmet requirement. If the design needs code-level control or logic that the available declarative features cannot express well, evaluate Apex for that specific gap.
- Inventory the full transaction. Include all relevant Flows, triggers, and other automation, then compare the combined work with Salesforce’s applicable transaction limits.
- Map save order and side effects. Determine which automations can update the same records; do not depend on an unguaranteed trigger order or assume a legacy update will cause automation to run again.
- Verify the target org’s constraints. Confirm edition- and Flow-type-specific limits, API-version details, security requirements, and which team will maintain and support the implementation.
Design for the team that will own the automation
Maintainability is part of the tool choice. A Flow is not automatically maintainable just because it is declarative, and Apex is not automatically the right fit just because a process has many steps. Choose the implementation that makes the requirement understandable, testable, secure, and supportable by the people responsible for future changes. For broader Salesforce guidance on automation choices and learning resources, see the Automation Best Practice Guide and Salesforce’s overview of Flows and Orchestrations.
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