Ostler vs Obsidian

Last verified on 26 April 2026. Pricing, features, and policies change – check the source if anything looks off.

Obsidian is brilliant. We mean that sincerely. Their local-first philosophy, their "not even us" privacy stance, their bootstrapped business model – we admire all of it. But they solve a different problem. Obsidian is for knowledge you write. Ostler is for knowledge you live.

	Ostler	Obsidian
Your data	Stays on your Mac	Stays on your device
Privacy model	Architectural (no server)	Local-first (no server)
Price	$49.99 once + $24.99/mo	Free personal / $50/yr commercial
Input method	Automatic import (20 platforms)	Manual note-taking
Relationship intelligence	Yes (warmth, reciprocity, history)	No
Personal wiki	Auto-generated, 21 page types	Manual wiki via Markdown
AI assistant	iMessage, WhatsApp, email	No (community plugins)
Conversation capture	Meeting + messaging	No
Knowledge graph	Automatic (vectors + RDF triples)	Manual (backlinks + graph view)
Plugin ecosystem	No	1,000+ community plugins
Works offline	Yes	Yes

Active versus passive knowledge

Obsidian requires you to write things down. Every note, every link, every connection – created manually. If you have the discipline for daily note-taking, Obsidian is extraordinary. The backlink system, the graph view, the plugin ecosystem – it is the best tool for deliberate knowledge management.

Most people do not have that discipline. Life gets busy. Notes pile up or never get written. The knowledge stays in your head, your messages, your emails – unorganised and unsearchable.

Ostler works passively. It imports your GDPR exports from 20 platforms, processes your conversations, captures your browsing history, and builds a knowledge graph automatically. You do not write notes about people you met – Ostler creates wiki pages from your existing data.

On what we share

Ostler and Obsidian share a core philosophy: your data should live on your device, not in someone else's cloud. Obsidian's "not even us" privacy stance is the gold standard in the industry. We designed Ostler with the same principle – architectural privacy, not policy privacy.

Both tools work offline. Both store data locally. Neither requires an account or sends telemetry. On privacy, we are aligned.

On complementarity

These tools are not really competitors. They are complementary.

Use Obsidian for deliberate thought. Meeting notes you want to structure. Ideas you want to develop. Projects you want to plan. Obsidian excels at active, intentional knowledge work.

Use Ostler for everything else. The thousands of relationships you cannot manually document. The years of conversations you will never have time to summarise. The 20 platforms of digital history that contain knowledge you have forgotten you have.

One is a thinking tool. The other is a memory system. Most people who would use Ostler could also benefit from Obsidian, and vice versa.

On price

Obsidian is free for personal use. That is hard to beat, and we do not try to. Obsidian's business model – bootstrapped, profitable, no VC – is admirable and something we respect.

Ostler costs $24.99/month because it runs AI inference, processes conversations, and maintains a knowledge graph continuously. The subscription covers compute-intensive features that a static note-taking app does not need. If you only want notes, Obsidian is free and better at it.

On the plugin question

Obsidian's plugin ecosystem is vast – over 1,000 community plugins. Some add AI features. Some add graph views. Some import data from external sources. In theory, you could cobble together something Ostler-like from plugins.

In practice, no one does. Each plugin is a separate project with separate maintenance, separate data formats, and no unified knowledge graph. Ostler is a single integrated system where every feature feeds the same graph. The difference between "possible with plugins" and "works out of the box" is the difference between a kit car and a production vehicle.