Key takeaways
- Start with Flow for record-triggered updates, guided screens and simple integrations. It is faster to build and easier for admins to maintain.
- Choose Apex when you need complex logic, large data volumes, fine-grained error handling or callouts that Flow handles poorly.
- Flow and Apex share the same governor limits, so a badly designed flow can fail just as hard as badly written code.
- Salesforce ends support for Workflow Rules and Process Builder on December 31, 2025. New automation should be built in Flow or Apex.
Almost every Salesforce project reaches the same fork in the road: should this automation be a Flow or should it be Apex? Teams often treat it as a matter of taste, admins prefer Flow and developers prefer code, but the right answer depends on the job. Choosing well saves money twice: once when you build, and again every time someone has to change it.
This guide explains what each tool is good at, where each one breaks down, and the questions we ask on client projects before deciding.
What Flow and Apex actually are
Flow is Salesforce’s declarative automation tool. You build logic visually in Flow Builder: record-triggered flows that run when records are created or updated, screen flows that guide users through a process, scheduled flows, and flows that respond to platform events. Salesforce has made Flow its strategic low-code tool and has been adding capability with every release.
Apex is Salesforce’s strongly typed programming language, similar in feel to Java. It runs on the platform in triggers, classes, batch jobs, queueable jobs and REST or SOAP services. Apex can do anything Flow can do, and a great deal more, but it requires a developer, unit tests and a deployment process.
The end of Workflow Rules and Process Builder
Salesforce has announced that it will end support for Workflow Rules and Process Builder on December 31, 2025. Existing automation may keep running after that date, but it will no longer receive customer support or bug fixes. Salesforce provides a Migrate to Flow tool that converts many of these automations, although complex processes usually need manual rework and testing.
If your org still relies on either tool, treat the migration as an opportunity to consolidate. It is common to find several workflow rules, a process and a trigger all acting on the same object, sometimes in conflict. Rebuilding them as one well-designed record-triggered flow, or one trigger framework, is often simpler than migrating each piece one to one.
When Flow is the right choice
- Field updates on the same record. Before-save record-triggered flows are fast and efficient for setting values when a record is saved.
- Creating related records and sending notifications. Creating a task, posting to Chatter or sending an email alert is straightforward in Flow.
- Guided user processes. Screen flows are excellent for intake forms, approvals with context and multi-step wizards.
- Logic that business users need to adjust. If thresholds, routing rules or criteria change often, admins can update a flow without a developer release.
- Simple integrations. HTTP Callout actions and External Services let Flow call well-documented REST APIs without code.
When Apex is the safer choice
- Complex logic. Deeply nested conditions, recursion control, sophisticated data transformations and algorithms are clearer and more testable in code.
- High data volumes. Batch Apex processes millions of records in manageable chunks, and well-written triggers handle bulk loads predictably.
- Robust integrations. Retries, custom authentication, request signing, large payloads and detailed logging are easier to get right in Apex.
- Precise error handling. Apex lets you catch specific exceptions, roll back partially, and decide exactly what the user or the integration sees.
- Reusable services. Logic shared by triggers, Lightning components and APIs belongs in Apex classes that can be called from anywhere, including from Flow as invocable actions.
Governor limits apply to both
A common misconception is that Flow is somehow exempt from Salesforce’s governor limits. It is not. Flows and Apex run in the same transaction and count against the same limits, such as the number of SOQL queries, DML statements and CPU time per transaction. A flow that queries or updates records inside a loop will hit these limits during a data load just like poorly written code.
| Limit (per transaction) | Synchronous | Asynchronous |
|---|---|---|
| SOQL queries | 100 | 200 |
| DML statements | 150 | 150 |
| CPU time | 10,000 ms | 60,000 ms |
| Heap size | 6 MB | 12 MB |
The practical rule is the same in both tools: query once, work with collections in memory, and write once at the end.
Questions we ask before deciding
- Who will maintain it? If you have an admin but no developer, a clean flow is often the more sustainable choice.
- How much data will pass through it? Thousands of records per hour, nightly syncs or migrations point towards Apex.
- How complex is the logic today, and in a year? Flows with dozens of decision elements become hard to read and test.
- What happens when it fails? If a failure must be retried, logged or reported to another system, Apex gives you more control.
- Is there an existing pattern in the org? Consistency matters. Mixing triggers and record-triggered flows on the same object without a clear order is a common source of bugs.
The best orgs use both
The most maintainable orgs we work on do not pick a side. They use Flow for straightforward, business-owned automation and screen experiences, and Apex for heavy lifting, packaged as invocable actions that flows can call. Each object has a documented automation strategy, so anyone opening the org knows where the logic lives.
Testing deserves a mention too. Apex requires unit tests with at least 75% coverage to deploy to production, which encourages discipline. Flows can be tested with flow tests and debug runs, but teams often skip this. Whichever tool you choose, test with realistic bulk data before you go live.
Frequently asked questions
Is Flow replacing Apex?
No. Flow is replacing Workflow Rules and Process Builder as the declarative tool. Apex remains the platform’s programming language for complex and high-volume logic.
Can a flow call Apex?
Yes. Apex methods annotated as invocable can be called from Flow, which is a good way to keep complex logic in code while letting admins orchestrate it.
Is Flow slower than Apex?
Before-save flows are very efficient for same-record updates. For complex processing or large volumes, well-written Apex is usually faster and more predictable.
