mq-dir vs Default Folder X: replace vs augment

Default Folder X (DFX) is one of the most uniquely positioned macOS utilities — it's been on the market for 20+ years, it has a dedicated 5-figure userbase, and most other Mac users have never heard of it. mq-dir is a much newer, much more visible tool in a different category. This post explains why neither replaces the other, and why heavy macOS users typically install both.

What each tool actually is

Default Folder X

DFX adds a sidebar to every macOS Open/Save dialog. The sidebar shows:

• Recent folders (across all apps)
• Favorites you've pinned
• Sets — saved groups of folders
• Path navigator (drill into ancestors)
• Tag-based filtering

It also lets you rename files mid-Save, set tags before save, and reveal in Finder from a dialog.

Critically: DFX hooks into macOS at the system level. It doesn't replace Finder, doesn't replace any app's UI — it just adds capability inside the dialog macOS shows when an app calls NSOpenPanel or NSSavePanel.

mq-dir

mq-dir is a standalone file manager — you launch it like any other app, navigate folders, manage files. It replaces Finder's role as the day-to-day file browser. It does not interact with Open/Save dialogs (those are owned by Finder/system).

They don't substitute

The most important point: these tools don't compete for the same job.

• DFX speeds up Open/Save dialogs.
• mq-dir replaces the file browser.

If you only had DFX, you'd still use Finder (or another file manager) for browsing.

If you only had mq-dir, you'd still face slow Open/Save dialogs across all your other apps.

The complementarity is genuine.

When DFX matters most

If you do any of these dozens of times a day:

• "Save this file under ~/dev/projects//screenshots/" (fast access)
• "Open the file I just saved 5 minutes ago" (recent files)
• "Tag this file at save time" (no separate step in Finder)
• "Open from one of these 8 specific folders I rotate between" (Sets)

DFX cuts each of these from ~20 seconds of folder navigation to one click.

For developers who save screenshots, drafts, exports, and downloads constantly across browsers, IDEs, design tools, and chat apps — the daily compound saving is enormous.

When mq-dir matters most

If you do any of these:

• Navigate between 3+ projects simultaneously with persistent state per project
• Run multiple AI agents and need to monitor their output folders in parallel
• Want a per-tab Markdown preview, image preview, video preview while browsing
• Need quad-pane layout for research / synthesis workflows
• Want full state persistence (folder + sort + scroll + focus + tabs all survive)

mq-dir replaces Finder for these. DFX doesn't enter the picture.

The combination

Most macOS power users who know about both run them together:

Finder        — kept around for AirDrop, Open/Save (when app forces it), occasional integration
mq-dir        — daily file browser
Default Folder X — adds sidebar/recent/sets to every Open/Save dialog (system-wide)

Total cost: $40 one-time for DFX. mq-dir is free.

Why mq-dir doesn't try to be DFX

Honest answer:

1. System-level hooks. DFX uses accessibility APIs and undocumented hooks that have taken 20 years to refine. Replicating this is a multi-year engineering project, and the result wouldn't be better than DFX.

2. Privacy posture. mq-dir's brand is zero telemetry, no system hooks, sandboxable. DFX-style integrations require entitlements that compromise this stance.

3. Scope. mq-dir scopes tightly to parallel work and persistence. Adding Open/Save dialog enhancement would be a sprawl into a different category.

4. DFX is great. No reason to build a worse version. If you need it, install it.

What DFX users will appreciate about mq-dir

If you're already a DFX user, you've thought hard about file management efficiency. mq-dir's selling points:

• Religious state persistence (every pane, every tab, every position).
• Quad-pane for genuine parallel work.
• Native macOS feel.
• Free, open source, MIT.

The mental model "I will not let the system reset my context" is shared by DFX and mq-dir. They apply it to different parts of the workflow.

What mq-dir users will appreciate about DFX

If you're an mq-dir user (or considering one), you'll quickly notice:

mq-dir doesn't help when you're saving from Photoshop, Logic, your IDE, your screenshot tool. Those apps' Open/Save dialogs are system-controlled. DFX is the unique tool that improves them.

The cost (~$40) pays back within days for users who save/open many files.

Use case routing

Verdict

There's no real comparison to make — DFX and mq-dir solve adjacent problems with no overlap. The right answer for serious macOS users is "install both."

DFX at $40 (one-time) is the highest-ROI macOS utility for save/open-heavy workflows. mq-dir is free and replaces Finder for navigation. Together they cover the file-management surface that Finder alone leaves rough.

mq-dir is MIT-licensed, no telemetry. DFX is closed-source from a small reputable developer (St. Clair Software, 25+ years on Mac). Both safe to commit to.

If you're forced to pick one: install whichever solves your bigger pain point first. Most users discover within a month that they want both.