Creating Links & Backlinks

A step-by-step tutorial for connecting your documents with typed, bidirectional links — the defining feature of Xudanu's Nelson-style hypertext.

1. What Are Links and Backlinks? 2. The Five Link Types 3. Creating a Typed Link 4. Creating a Transclusion 5. Creating a Cross-Server Link 6. Managing Your Links 7. Understanding the Visual Markers 8. The Connections Panel 9. Tips and Best Practices

1. What Are Links and Backlinks?

In Xudanu, a link is a typed, bidirectional connection between two passages of text. Unlike ordinary web links (one-way, one-to-one), Xudanu links are:

A transclusion is a special kind of link that copies content from one document into another while maintaining the connection to the original. Think of it as "live quoting" — the quoted text always traces back to its source.

ESSAY "privacy is a human right" LINK TYPE REVIEWER NOTES "this claim is contested" BACKLINK C D

A Comment link from Essay to Reviewer Notes. The blue "C" bar marks the outgoing link; the red "D" marks the disagreement response. The green dashed arrow shows the automatic backlink.

2. The Five Link Types

Each link type has a distinct colour and underline pattern. This makes overlapping links readable even in dense documents.

Comment Annotate a passage Reference Citation, "see this" Disagreement Contested claim Quotation "This quotes..." See Also Related reading
TypeColourUse When
CommentBlue, dashedYou want to annotate or add a scholarly note to a passage
ReferenceGreen, solidCross-referencing, citing a source, "see this section"
DisagreementRed, long dashYou disagree with a claim and want to link your counter-argument
QuotationPurple, dottedThis passage is a quote from another document
See AlsoAmber, dash-dotRelated reading path or similar work

3. Creating a Typed Link

A typed link connects two passages with a semantic relationship. This is the most common type of connection.

1 Select the source text

Open the document you want to link from. Highlight the passage you want to connect.

Many argue that privacy is a human right and that any backdoor, however well-meaning, undermines the entire guarantee.

Two buttons will appear above the selection: Transclude and Link.

2 Click "Link"

Click the Link button. The Link Creator wizard opens, showing your selected text as the source.

Create Link
From: Essay on Privacy
“privacy is a human right”
What do you want to link this to?
Link to an entire document
Pick a document from your library
“”
Link to specific text in another document
Navigate to another document and select a passage
Link to another part of this document
Select different text in the same document
Link to a remote server
Connect to content on another Xudanu server
3a Option A: Link to an entire document

Choose "Link to an entire document". A list of your documents appears. Click the one you want to link to.

Then pick a link type and click Create Link. The link is created immediately — no need to navigate to the other document.

Link type
Linking to: Reviewer Notes
Comment
Annotate a passage or add a scholarly note
Reference
Cross-reference, citation, or "see this"
Disagreement
Mark a contested claim or counter-argument
Quotation
This passage quotes another source
3b Option B: Link to specific text in another document

Choose "Link to specific text in another document". The wizard closes and a yellow action bar appears:

Linking from “Essay on Privacy” — select target text

Now navigate to the target document (click it in the library sidebar) and highlight the passage you want to link to. The action bar will show link type buttons:

Link type: Comment Reference Disagreement Quotation See Also

Click the type you want. The link is created!

Press Esc at any time to cancel.

4 The link appears

The linked passage now shows a coloured underline and a margin bar. Hover over the marker to see a tooltip with the target document, link type, and excerpt. Click to navigate to the linked document.

4. Creating a Transclusion

A transclusion copies content from one document into another while maintaining the provenance link to the source. This is useful when you want to quote a passage verbatim and have it visible inline.

1 Select the source text

In the source document, highlight the passage you want to transclude.

2 Click "Transclude"

Click the Transclude button. A floating badge appears showing the held selection.

Transcluding from: Canon “privacy is a human right” Place at cursor
3 Navigate and place

Navigate to the destination document. Click Place at cursor on the badge, or simply click in the editor where you want the transclusion inserted.

The transcluded text appears inline with a hatched margin bar, and a provenance chain connects it back to the original source.

Tip: Transclusions have no link type — they are always rendered with a hatched pattern, not a coloured underline. If you want to type a transclusion (e.g., mark it as a Quotation), create a separate typed link in addition to the transclusion.

5. Creating a Cross-Server Link

Xudanu servers can link to each other. A cross-server link connects a passage on your server to content on a remote Xudanu server. The link persists across restarts and carries the remote content's cryptographic hash for tamper verification.

YOUR SERVER (xudanu.com) LOCAL ESSAY "privacy is a human right" REMOTE SERVER (alice.example.com) REMOTE CANON "the original source text" CROSS-SERVER LINK BLAKE3 hash verified Content fetched via HTTPS · cached locally · tamper-evident

A cross-server link connects a local passage to remote content. The remote server's content is fetched, verified against a BLAKE3 hash, and cached locally.

1 Select source text and open the wizard

As with any link, select the passage in your document and click Link. In the wizard, choose "Link to a remote server".

2 Enter the tumbler

The tumbler is the Xanadu global identifier for the remote content. It takes one of two forms:

FormatExampleWhen to use
Domain"alice.example.com".5.3.10.7Preferred — human-readable, self-routing via DNS
Numeric1.5.3.10.7When the server has a registered numeric ID in your directory

The tumbler components are: server . work_id . version . revision . edition

3 Enter the content hash

Provide the BLAKE3 content hash (64 hex characters) from the remote server. This is used to verify that the fetched content has not been tampered with. You can find this hash on the remote server's public content API or from a shared reference.

Remote server link ← back
Tumbler
"alice.example.com".5.3.10.7
Content hash (BLAKE3, hex)
a1b2c3d4e5f6...(64 chars)
Author name (optional)
alice
4 Optionally enter author info

You can add the remote author's name and public key (hex). This information is stored with the link and can be used for attribution and provenance verification. If omitted, the author defaults to "unknown".

5 Click "Create Remote Link"

The link is created. The remote server's content is fetched on demand when the link is resolved, verified against the stored hash, and cached locally for fast subsequent access.

Tumbler format: The domain format "server.address".work_id.v.revision.edition is preferred because it's self-routing — the client can look up the server via DNS. The numeric format server_id.work_id.v.revision.edition requires the server ID to be registered in your local server directory.
Hash verification: When a cross-server link is resolved, the fetched content's BLAKE3 hash must match the stored hash. If it doesn't, the resolution fails with a tamper warning. This ensures that content cannot be silently altered on the remote server.

6. Managing Your Links

You can manage existing links from the Connections panel on the right side of the screen. Each link shows:

Connections
link ⇄ Reviewer Notes
“this claim is contested in case law…”
backlink ← Rebuttal Essay
“see Doe 2021 §4 for a counter-argument…”

To use the management controls:

  1. Change type: Click the dropdown next to any link and select a new type. The underline colour and pattern update immediately.
  2. Delete: Click the × button. The link is removed from both documents.
  3. Navigate: Click anywhere on a connection item to jump to the connected document.
  4. Pin: Click the ☆ star to pin important connections to the top.
  5. Filter: Use the dropdown at the top of the panel to filter by All, Pinned, Transclusions, Links, or Backlinks.
Delete from the document: You don't have to open the Connections panel to delete a link. Simply hover over the link's margin bar in the document and the tooltip that appears includes a red × Delete link button. This works for any typed link, even if it has no description. Click it and the link is removed from both documents immediately.
Note: Link management controls only appear when you have edit access to the current document. If you are viewing a read-only document, you can see links but not modify them.

7. Understanding the Visual Markers

When links exist on a passage, you will see three visual elements:

Many argue that privacy is a human right L left bar (outgoing) underline (type style) right bar (incoming) invisible hit zone (hover → tooltip, click → navigate)

Anatomy of a link marker: left margin bar (outgoing), coloured underline (type style), right margin bar (incoming), and invisible hit zone for interaction.

Margin bars

PositionMeaningColour
Left marginThis document links OUT to another documentLink type colour
Right marginAnother document links IN to this passageGreen
Left margin (dashed)Cross-server link OUT to a remote serverAmber, dashed border

Cross-server link markers

Links to remote servers display with a distinct amber dashed border pattern to distinguish them from local links. The marker tooltip shows the remote server's address, tumbler, and author information. If the remote content has been cached locally, clicking the marker navigates to a read-only view; if not yet cached, the server fetches and verifies it on first access.

When links overlap

Multiple links on the same passage are rendered in separate vertical lanes, each offset by 2px so all remain visible. When five or more links overlap in a region, they collapse into a single amber density pill showing the count. Click the pill to expand the cluster.

6 privacy is a human right Click the amber pill → cluster expands

Description boxes and connecting lines

When a link has a description, a coloured description box appears in the right margin showing the link type label and the description text. A dotted connecting line runs from the box to the source text, anchoring to the underline of the linked passage (the bottom of the text, not the centre). When multiple links overlap, the connecting lines use lane separation so each remains distinguishable.

Tooltip with delete button

Hovering over any link marker (margin bar, underline hit zone, or density pill) shows a tooltip with the target document title, link type, text excerpt, and action buttons: Go to, Trace provenance, and a red × Delete link button. The delete button works for any typed link — no need to open the Connections panel.

8. The Connections Panel

The Connections panel on the right side of the screen gives you a unified view of all connections for the current document:

SectionWhat It Shows
TransclusionsInline transcluded content from other documents (amber border)
LinksTyped links you created from this document (blue border)
BacklinksLinks from other documents pointing into this one (green border)
Cross-serverLinks to content on remote Xudanu servers (amber dashed border)

Use the dropdown at the top to filter by type. Pin important connections with the star (☆) to keep them at the top. Click any item to navigate to the connected document.

Direction matters: The same link appears differently depending on which document you're viewing. In the origin document, it shows as a link (⇄, outgoing, left margin). In the destination document, it shows as a backlink (←, incoming, right margin).
Related footer: In addition to the Connections panel, a collapsible Related bar appears at the bottom of the document. It shows backlinks, outgoing links, transclusion sources, and cross-server references in a compact list. Each item displays a reason label (e.g., "Referenced by", "Includes content from"), the connected document's title, and a text excerpt. This is an alternative way to discover connections without opening the side panel.

9. Tips and Best Practices

Choose the right type. Think about the semantic relationship. Is this a note on the passage? Use Comment. Is it a counter-argument? Use Disagreement. Is it a direct quote? Use Quotation. Getting the type right makes the document's connection graph more meaningful.
Links survive edits. When you insert or delete text, link spans migrate automatically. You don't need to re-create links after editing.
Overlapping is fine. Multiple users can create links on the same passage without coordination. The canvas layers them into lanes so all remain visible.
Transclusion vs. Link: Use Transclude when you want the source text to appear inline in your document (live quote). Use Link when you want to connect passages without copying text (annotation, cross-reference).
Backlinks are automatic. You never create a backlink directly. When document A links to document B, B automatically sees the incoming link in its Connections panel. This is the bidirectional nature of Xudanu links.
Persistence: All links are durably stored. They survive server restarts, crashes, and work archival. When you publish a document, its links become visible to other users.
Cross-server links are permanent: Cross-server links store the remote content's BLAKE3 hash, tumbler, and author info. They survive checkpoint, restore, and WAL replay. Even if the remote server goes offline, the link's metadata (excerpt, hash, provenance) remains intact. When the remote server returns, the link can be resolved again.
Remote content caching: When a cross-server link is resolved, the fetched content is cached in the local blob store. Subsequent accesses are instant. The cache can be cleared by the server operator, but the link itself — with its hash, tumbler, and excerpt — is permanent proof of the connection.

Keyboard shortcuts

KeyAction
EscCancel pending link/transclusion creation
Ctrl + KOpen search
Click markerNavigate to the linked document
Double-click markerJump to linked document and show its connections
Hover markerShow tooltip with target, type, excerpt