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Fn

Run any Dockerized function anywhere with event-driven simplicity

Serverless Platforms

Fn is a cloud‑agnostic, event‑driven FaaS platform that lets developers deploy any Docker container as a function, while operators manage it across public, private or hybrid clouds.

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Overview

Overview

Fn provides an event‑driven compute platform that turns any Docker container into a serverless function. Developers can write code in their language of choice, package it as a container, and deploy it with a simple CLI.

Audience & Deployment

Designed for developers seeking language‑agnostic, container‑native functions and for operators who need a lightweight, extensible platform that runs on‑prem, in public clouds, or in hybrid environments. The platform runs locally with an embedded database and message queue, or can be scaled using external orchestration tools.

Capabilities

Fn supports importing AWS Lambda functions, offers a straightforward API, and integrates with sub‑projects like Flow, UI, and FnLB. Its Go‑based core and Docker‑native approach ensure portability and ease of extension across diverse infrastructures.

Highlights

Native Docker support – any container can be a function
Runs on any infrastructure – local, on‑prem, public or hybrid cloud
Language‑agnostic – supports Go, Node, Java, Python, etc.
Extensible platform written in Go with simple CLI

Pros

  • Broad language support via Docker
  • Zero‑vendor lock‑in, can run anywhere
  • Lightweight CLI accelerates development
  • Open‑source Apache‑2.0 license encourages community contributions

Considerations

  • Requires Docker runtime, adding container overhead
  • Operator must manage underlying infrastructure and message queue
  • Limited built‑in UI compared to some commercial platforms
  • Scaling beyond single‑node needs external orchestration (e.g., Kubernetes)

Managed products teams compare with

When teams consider Fn, these hosted platforms usually appear on the same shortlist.

AWS Lambda logo

AWS Lambda

Serverless compute service that runs code in response to events without provisioning or managing servers

Azure Functions logo

Azure Functions

Serverless compute service in Azure for running event-driven code without managing infrastructure

Google Cloud Functions logo

Google Cloud Functions

Event‑driven serverless compute for running code on demand

Looking for a hosted option? These are the services engineering teams benchmark against before choosing open source.

Fit guide

Great for

  • Teams that want serverless workloads without vendor lock‑in
  • Developers who prefer container‑based functions in any language
  • Enterprises deploying hybrid cloud or on‑prem serverless services
  • Organizations seeking an extensible platform with a simple CLI

Not ideal when

  • Use cases demanding fully managed, zero‑ops serverless platforms
  • Workloads that cannot tolerate Docker container startup latency
  • Teams requiring out‑of‑the‑box UI dashboards and analytics
  • Projects needing automatic multi‑region scaling without extra orchestration

How teams use it

API endpoint for image processing

Deploy a Go or Python function in a Docker image that scales on demand to handle image transformations

Event‑driven data pipeline

Trigger functions from message queues to enrich or route data without managing servers

Legacy Lambda migration

Import existing AWS Lambda code and run it on‑prem or in any cloud via Fn

CI/CD custom step

Run containerized build or test steps as functions within a CI workflow, reducing pipeline complexity

Tech snapshot

Go97%
Shell1%
Ruby1%
Makefile1%
Dockerfile1%
PowerShell1%

Tags

kubernetescontainersserverless-functionslambdafaasserverlessdockerswarm

Frequently asked questions

Do I need to use the Fn CLI?

The CLI is not required but simplifies creating, deploying, and invoking functions; you can also interact via the REST API.

Can I run Fn on Kubernetes?

Yes, Fn can be deployed on Kubernetes using the provided Helm charts or custom manifests.

Is there a cost to use Fn?

Fn itself is free and open source; you only incur infrastructure costs for the underlying resources you run it on.

How does Fn handle function scaling?

Fn relies on the underlying platform (Docker, Kubernetes, etc.) to scale containers; you can configure autoscaling policies externally.

What languages are supported?

Any language that can be packaged into a Docker container is supported, including Go, Node.js, Java, Python, Ruby, and more.

Project at a glance

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LicenseApache-2.0
Repo age8 years old
Last commit20 hours ago
Primary languageGo

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