Notesach

Notesach is a cross-platform open-standard for personal knowledge management and note-taking. It defines a portable data format and a set of conventions for organizing notes, linking them, and enabling long-term archival and interoperability between applications. While primarily used as a personal tool, Notesach aims to support collaboration through shared notebooks and standards-compliant exports.

Data and structure: Notes are stored in files with a .notesach extension containing structured records. Each note includes an identifier, title, content written in Markdown, metadata such as created and modified timestamps, tags, and an array of links to other notes. A backlinks index tracks reverse references to support graph-based navigation. The format emphasizes portability: notes can be exported to JSON, HTML, or PDF, and imports from Markdown-plus-front-matter are supported.

Features: Notesach emphasizes offline-first operation, encryption for local storage, and version history. It supports bidirectional links, searchable full text and tag queries, and lightweight rendering of embedded data blocks. The format is designed to be human-readable and resilient to software evolution, with backward-compatible schema updates.

History and status: The project emerged in the open-source community in the mid-2010s as a response to fragmented note formats. A reference implementation and several community plugins exist in multiple programming languages. As of the latest releases, many knowledge-management tools provide limited support for Notesach through adapters and exporters.

Reception: Notesach has attracted interest among users seeking long-term data portability and semantic linking, but adoption remains limited relative to proprietary ecosystems. Critics point to complexity and the need for explicit tooling to realize its full graph-based capabilities.

See also: Zettelkasten, Obsidian, Roam Research, Markdown, knowledge management.