Recommended Free Tools
Use ordinary functions for calculations and business logic that do not need a runtime process. Use a plain Elixir process when you deliberately need a custom message loop or a small, specialized lifecycle. Choose a GenServer or another OTP behaviour when a component needs persistent process state, a standard request protocol, system-message support, or a supervised lifecycle.
These are not different kinds of BEAM execution: a GenServer is an Elixir process with a conventional interface and lifecycle support. The useful question is not “OTP or processes?” but “What runtime behavior does this component actually need?”
Do I need a GenServer for this?
Usually not for logic that can be expressed as a direct function call. Elixir’s GenServer documentation cautions against using a GenServer merely to organize code: funneling unrelated operations through one server adds message handling and can serialize work behind a single mailbox. That is an architectural risk, not proof that GenServers are always slower; profile the real workload when throughput matters.
The documentation’s concise rule is: “If you don’t need a process, then you don’t need a process.” For a calculator, for example, add/2 and subtract/2 should ordinarily be functions, not requests routed through a GenServer. See the GenServer guide.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →#1 Best Overall
When should I use a GenServer?
Use a GenServer when the component has a meaningful runtime identity and benefits from the standard client-server process model. It is an ordinary Elixir process that can retain state and run code asynchronously; the behaviour provides callbacks and standard interfaces for synchronous calls and asynchronous casts.
- State that lives between requests: a process can own mutable in-memory state and update it as messages arrive.
- A defined request protocol: callers can use standard call and cast interactions rather than each module inventing its own conventions.
- OTP lifecycle integration: a GenServer can be started as a child under a supervisor, making startup, shutdown, and recovery policy part of the application structure.
- System-level process needs: GenServer supports system messages, including periodic messages and monitoring events, and can be registered under a name.
The behaviour also supplies tracing and error-reporting functionality and abstracts the receive loop. Keep domain logic in ordinary functions where that makes it reusable and independently testable; callbacks should coordinate the process protocol rather than become a home for all application logic. The GenServer reference documents the callbacks and supported interactions.
When should I use a plain Elixir process?
A plain process is a reasonable choice when you genuinely need a message loop but GenServer’s conventional call/cast protocol and lifecycle abstraction do not fit. For example, a specialized receive protocol or unusual lifecycle can justify handling messages directly. That flexibility comes with responsibility: you must design message handling, termination, monitoring, and failure behavior rather than assuming OTP has supplied them.
Processes communicate by sending messages. Links can propagate abnormal exits to linked processes that are not trapping exits, but a bare spawn is not a restart strategy. If the application depends on a process being restarted or on coordinated shutdown, specify that lifecycle intentionally, commonly through a supervisor. The Process reference describes process and link behavior.
Free tools Windows power users keep installed
One-click scans. No signup required.
Rank #3
For a single concurrent computation rather than a long-lived stateful service, consider a task abstraction or a small plain process according to the required lifecycle. Make result collection, cancellation, and failure handling explicit; concurrency alone does not imply that a GenServer is needed.
When should I use OTP behaviours?
Use the OTP behaviour that matches the component’s protocol and lifecycle needs. GenServer is the familiar client-server option, but the broader decision is whether the component needs the standard interfaces and system integration that a behaviour provides. The goal is not to add OTP ceremony everywhere; it is to use common process machinery when it makes the runtime contract clearer and easier to manage.
A supervisor is itself a process. It manages child processes in a hierarchy called a supervision tree, which provides a structure for fault tolerance and for application startup and shutdown. A module using use GenServer supplies a child specification so it can be started beneath a supervisor. Supervision defines lifecycle and recovery around a process; it does not make that process a different execution primitive. See the Supervisor reference.
Choose by runtime requirement, not by code organization
| Situation | Starting point | Reason |
|---|---|---|
| Calculation, validation, transformation, or domain logic | Functions and modules | No process identity or retained runtime state is required. |
| One isolated concurrent computation | A task abstraction or a small plain process | The work is concurrent, but may not need a long-lived stateful server. Choose based on lifecycle and make result and failure handling explicit. |
| Long-lived in-memory state with serialized updates | GenServer or a more specific OTP behaviour | The process owns state and handles a protocol through standard callbacks. |
| Named service, periodic work, system messages, monitoring, or supervised lifecycle | GenServer or the behaviour matching the protocol | OTP offers conventional process interfaces and integrates children with supervision. |
| Custom receive protocol or unusual lifecycle | Consider a plain process if the custom behavior is a real requirement | GenServer abstracts the receive loop and its system interactions; custom loops require deliberate lifecycle and failure handling. |
This is a starting-point guide, not a performance ranking. A single GenServer can become a serialization point when unrelated requests share its mailbox, but there is no universal speed result for “plain process versus GenServer.” Measure the application’s actual workload if performance is decisive.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Best Value
Check version compatibility before relying on release details
As of October 4, 2026, the official Elixir documentation index lists v1.20.4 as stable and Erlang/OTP 27, 28, and 29 as supported for that Elixir release. This compatibility information is time-sensitive; check the index and the requirements of your own project before choosing an installation or upgrade target.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
