What is Kosshi?

Kosshi is a native outliner for macOS and iOS that focuses on fast, distraction-free editing. Built from the ground up with Apple frameworks and a custom rendering engine, it handles everything from quick notes to massive outlines with 100,000+ rows without lag. Data stays on your device, syncs privately through iCloud, and costs a one-time $24.99 — no subscriptions, no accounts, no developer servers involved.

Who it's for

• Writers and note-takers who want a clean, hierarchical workspace without the overhead of a full note-taking suite
• Project managers and planners who need to organize tasks, deadlines, and dependencies in a single, zoomable outline
• Privacy-conscious users who insist on local-first storage and end-to-end sync that never touches a third-party server

Key features

Native performance at any scale

The rendering engine is written from scratch on Apple frameworks. Typing, collapsing, dragging, and searching all respond instantly — even past 100,000 rows. This matters because an outliner repeats these operations constantly, and speed defines how the tool feels.

iCloud sync with zero server costs

Data lives locally on your device. Sync uses Apple's CloudKit, so your outline data passes through your iCloud account only — never through a developer server. No server costs means no subscription, no sign-up, and no account required.

Zoom and breadcrumb navigation

You can zoom into any row to focus on its contents alone. Breadcrumbs show your location in the hierarchy, and a single tap jumps you back to the full outline. This makes deep outlines navigable without losing context.

Inline Markdown with clean editing

Bold, links, checkboxes, and other formatting render right where you type. Formatting markers appear only while editing and disappear when you move away — so your outline stays readable and uncluttered.

What stands out

"An outliner that stays fast at 100,000 rows — and never asks for a subscription."

Most outlining apps slow down as your data grows or lock advanced features behind monthly fees. Kosshi solves both problems at once: its custom layout engine keeps response speed consistent even with years of accumulated notes, and the one-time $24.99 price covers everything — including iCloud sync, Markdown export, and Apple Reminders/Calendar integration. There is no tiered pricing, no feature gating, and no data leaving your iCloud account.

Worth checking out if…

You want a native, offline-first outliner that doesn't compromise on speed or privacy. If you've been frustrated by web-based tools that lag with large outlines, or by subscription apps that charge monthly for basic sync, Kosshi offers a clean alternative. It's especially useful if you prefer keeping everything in one outline and zooming into sections as needed, rather than juggling dozens of separate documents.