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Nodian

An Obsidian plugin that automatically syncs bidirectional relations in YAML frontmatter.

When you add a wikilink to a field in one file, the plugin writes a backlink in the target file's corresponding field — and removes it when you delete the link.

Example

Person.md                          Mail.md
─────────                          ─────────
tags: [Person]                     tags: [Mail]
Mail: [[hello@example]]     →     Person: [[Alice]]        ← auto-generated

Features

• Auto sync — add or remove a link in one file, the other side updates instantly
• Relation pairs — define which fields are paired (e.g. Mail ↔ Person, Artist ↔ Songs)
• Tag-based matching — each pair requires tags; sync only fires when both field and tag match
• Display names — optionally use title field as display text in backlinks
• New file support — creating a file from a wikilink auto-adds tags and backlinks
• Full sync command — manually sync all relations via Command Palette
• Localized — English, Japanese, Traditional Chinese
• Mobile support — works on both desktop and mobile

Works well with Obsidian Bases

Nodian can connect different Bases through typed YAML relations.

For example, you can have one Base filtered by #Person and another Base filtered by #Mail. When a Person note links to a Mail note through the Mail field, Nodian automatically writes the reverse Person field in the Mail note.

Because every relation pair requires tags on both sides, the same field name can safely be used in different Bases without triggering the wrong relation.

Install

With BRAT (recommended)

1. Install BRAT from Community Plugins
2. BRAT → Add Beta Plugin → AkiSantin/Nodian

Manual

Copy main.js, manifest.json, and styles.css to:

<vault>/.obsidian/plugins/nodian/

Restart Obsidian → Settings → Community Plugins → Enable Nodian.

Getting Started

Step 1: Set up your first pair

Open any .md file and add a wikilink to a YAML field:

---
tags: [Person]
Mail: "[[hello@example]]"
---

Right-click the property name → select Configure bidirectional relation.

In the modal, set the counterpart field (e.g. Person) and tags, then press Save.

Step 2: Verify

Open [email protected] — you should see:

---
tags: [Mail]
Person: "[[Alice]]"
---

That's it. From now on, any file's Mail field will automatically sync with the target file's Person field.

Step 3: Run full sync (existing vaults)

If your vault already has existing relations, run a one-time full sync:

Command Palette (Cmd/Ctrl+P) → Sync all bidirectional relations

This scans every file and backfills any missing backlinks.

Usage Guide

Adding a link

Add a wikilink to any paired field. The backlink appears in the target file automatically.

# You type this in Artist.md:
Songs: "[[Blue Sky]]"

# Plugin auto-generates this in Blue Sky.md:
Artist: "[[Artist Name]]"

Removing a link

Delete the wikilink from the field. The backlink in the target file is removed automatically.

Multiple links

A field can hold multiple wikilinks:

Songs:
  - "[[Blue Sky]]"
  - "[[Red Moon]]"
  - "[[Green Field]]"

Each target file gets its own backlink. Removing one link only affects that specific target.

Self-relations

A field can be paired with itself:

Related ↔ Related

Adding Related: [[B]] in A.md will add Related: [[A]] in B.md.

Display names

By default, backlinks use the plain filename: [[my-artist-id]].

To use the title field as display text, enable Use title as display name in Settings. Backlinks will appear as [[my-artist-id|Some Artist Name]] (using the value of the source file's title frontmatter field). Only the title field is used — aliases are not checked.

Toggling this setting does not retroactively update existing backlinks. After changing it, run Sync all bidirectional relations from the Command Palette to update all backlinks across the vault.

New file creation

If you link to a file that doesn't exist yet:

Mail: "[[new-contact]]"

When new-contact.md is created (e.g. by clicking the link in Obsidian), the plugin will:

1. Add the appropriate tag to the new file
2. Write the backlink automatically

Tags

Every relation pair has two tags — Tag A and Tag B — that correspond to Field A and Field B. Tags are required, not optional.

How tags work

The plugin only syncs when both conditions are met:

1. The source file has a field that matches a pair's field name
2. The source file's tag matches that pair's corresponding tag

This prevents wrong-target sync. For example, if both Release files and Song files have an Artist field, the tag ensures each pair only fires for the correct file type — a Release-tagged file uses the Artist ↔ Release pair, while a Song-tagged file uses the Artist ↔ Song pair.

Automatic tag assignment

• When you set up a pair through the context menu, the source file's tag is used automatically.
• When a new file is created from a wikilink, the plugin auto-assigns the appropriate tag from the pair definition.

Settings

Go to Settings → Nodian.

Relation Pairs

Add, edit, or remove field pairs. Each pair defines two field names and two tags that are bidirectionally linked.

Pair Examples

Each pair also has Tag A and Tag B configured alongside the fields in Settings. The tables below show the field pairings only — tags are assigned through the settings or context menu when you create each pair.

A music vault:

A company/CRM vault:

Important Notes

• Back up your vault before first use. This plugin modifies YAML frontmatter directly. While it only touches fields defined in your pairs, unexpected formatting changes are possible if you have complex custom YAML.
• Deleting a file does not remove backlinks pointing to it — those become unresolved links (by design, to prevent accidental data loss).
• Renaming a file is handled by Obsidian's built-in link updater — the plugin doesn't need to do anything extra.
• Duplicate pairs (e.g. A ↔ B and B ↔ A) are redundant — one pair covers both directions.
• Duplicate basenames — files with the same name in different folders may cause incorrect sync targets. Use unique filenames to avoid ambiguity.
• System fields (title, aliases, tags, cssclasses, publish, etc.) cannot be used as relation fields.

License

MIT