---
title: "Functions FAQ"
description: "This page answers the most frequently asked questions about CircleCI functions."
platform: "Cloud"
doc_version: "unversioned"
last_updated: "2026-11-03"
---

> For current CircleCI product defaults, deprecated patterns, and Cloud/Server differences, see [AGENTS.md](https://circleci.com/docs/AGENTS.md).
>
> For the complete documentation index and site structure, see [llms.txt](https://circleci.com/docs/llms.txt).

# Functions FAQ Beta

## FAQs

### What is the difference between functions and orbs?

Orbs package reusable configuration. Functions are programs that run as steps inside your jobs. For a side-by-side comparison, refer to the [Functions and Orbs](https://circleci.com/docs/functions/functions-concepts/#functions-and-orbs) section.

### Can I use functions and orbs in the same configuration?

Yes. Declare orbs under `orbs` and functions under `functions` in the same configuration file. Give each function an alias that does not clash with an orb name.

### Which version of a function do I use?

Use the latest version unless you need a specific one. To see every published version, run `circleci function get <name>`. To declare a function at its latest version, run `circleci function add <name>`.

### Why do I need to pin an exact version?

An exact version means every run uses the same function, until you choose to update it. Partial versions such as `v0` and labels such as `latest` fail validation. To move to a newer release, run `circleci function update <alias>`.

### Why does my configuration fail validation after I change a function version?

CircleCI checks each function step against the version you pin. If the new version renamed or removed a flag or command that your step uses, validation fails and the error lists the valid flags or commands. Update the step to match, then run `circleci config validate` to check it.

### How do I see the flags a function accepts?

Read the function’s README, linked from the [Functions Catalog](https://circleci.com/docs/functions/functions-catalog/), or run `circleci function get <name>`.

### Do I need to add cache steps when I use a function?

No. Functions that support caching manage their own caches. Refer to [How Functions Run](https://circleci.com/docs/functions/functions-concepts/#how-functions-run).

### Which executors can I use functions on?

Functions run inside your job, on the executor the job uses. Supported operating systems and architectures differ by function, and each function’s README lists them under **Platform support**.

### Can I use functions on CircleCI Server?

No. Functions are available on CircleCI Cloud only.

## See also

*   Refer to [Functions Overview](https://circleci.com/docs/functions/functions-intro/) for a starting point on using functions.
    
*   Refer to [Functions Concepts](https://circleci.com/docs/functions/functions-concepts/) for high-level information about CircleCI functions.