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Fylune

Free
★ 45 • Updated Sep 22, 2026, 09:26 PM

Fylune is a free document editor offered both as a desktop application (currently a macOS alpha) and as a browser-based editor.

Use Cases ▼
01

Editing Markdown documentation and notes stored in local project folders

02

Writing MDX content that includes tables, checklists, and Mermaid flowcharts or mind maps

03

Reviewing and editing JSON and JSONL data files offline without a cloud login

04

Filling out official California court and DMV PDF forms online and downloading the results

05

Managing local images and media with automatic asset copying and relative path generation

06

Drafting new documents alongside the files that already explain a project

What Problem It Solves ▼

People who write and maintain Markdown, MDX, JSON, or JSONL files in local folders often have to choose between plain-text editors that lack diagram, formula, and preview support and IDEs that feel heavy for writing. Separately, filling official government PDF forms usually requires printing them or installing dedicated PDF software. Fylune combines a local-first plain-text editor with an online official PDF form filler in one free tool.

Key Features ▼
✓

Local-first design keeps files on the device with no account required for the core editing loop

✓

Core editor is free with unlimited local documents

✓

Rich Markdown support including Mermaid diagrams, KaTeX formulas, tables, and checklists

✓

Includes an online library of official fillable PDF forms

✓

Automatic asset management copies media into the project and writes relative paths

Overview

Fylune is a free document editor offered both as a desktop application (currently a macOS alpha) and as a browser-based editor. It opens Markdown, MDX, JSON, and JSONL files that already live inside local folders and edits them in place, so ordinary files stay readable by Finder, other editors, and AI tooling. No account is required for the core editing loop, and editing works offline by default.

Full Description ▼

The editor aims to cover the Markdown features that usually push writers back into an IDE: GFM tables, checklists, code blocks, media, Mermaid flowcharts and mind maps, KaTeX formulas, and richer MDX blocks. Its preview is deliberately safe, meaning MDX and JavaScript are rendered as source rather than executed. Dropping or pasting an image, video, or document copies the asset into the project beside the file that uses it and writes the relative Markdown path automatically.

Alongside local editing, Fylune hosts a library of official PDF form templates that can be filled in the browser and then downloaded or saved to a Fylune cloud account. The listed templates focus on California forms, such as Judicial Council forms MC-025 and MC-030 and DMV forms REG 101, REG 135, REG 156, and REG 256.

The core editor is free, including unlimited local documents, search and file navigation, and built-in components. Paid plans apply to optional cloud and advanced collaboration services rather than to access to local files. The product markets itself as local-first by default.

Pros & Cons

Pros

+

Local-first design keeps files on the device with no account required for the core editing loop

+

Core editor is free with unlimited local documents

+

Rich Markdown support including Mermaid diagrams, KaTeX formulas, tables, and checklists

+

Includes an online library of official fillable PDF forms

+

Automatic asset management copies media into the project and writes relative paths

Cons

−

Desktop build is macOS-only and in alpha, so Windows and Linux users depend on the web editor

−

Cloud saving and collaboration features require an account and paid plans

−

MDX and JavaScript do not execute in the safe preview, limiting component testing

−

The official form template library currently appears focused on California forms

−

Licensing and platform roadmap details are not clearly documented on the homepage

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