How to use Yellorn
Seven steps from a fresh editor tab to publishing your first mock REST endpoint, plus the keyboard shortcuts that earn their keep.
Walkthrough
Each step builds on the previous one — but each one stands alone, so feel free to jump ahead.
Paste anything structured
Open the editor and paste JSON, XML, YAML, or CSV. Yellorn detects the format automatically and switches the active plugin once confidence crosses 90%. You can override the detection from the format selector in the toolbar.
The visualizer (Tree / Graph / Table) updates as you type — every plugin declares which views it supports, so CSV defaults to Table while JSON / XML / YAML default to Tree.
Repair broken input with Smart Format
Press Cmd + Shift + F (or Ctrl + Shift + F on Windows / Linux) to run Smart Format. It applies the format-specific recovery ladder — 15 fixes for JSON, 5 for XML, 6 for YAML, 3 for CSV — then pretty-prints the result.
Every applied fix is labelled in the status bar (
Auto-fixed: trailing-commas, single-quotes) so you consent to every transformation before publishing.Convert between formats
Click Convert to… in the editor toolbar to swap the active format. JSON ↔ XML ↔ YAML ↔ CSV ↔ Python is supported with structural-compatibility checks; lossy conversions surface a warning toast first. One Cmd + Z reverts both the text and the format together.
Publish a payload as a mock REST endpoint
Sign in (free) and click Publish in the toolbar. Yellorn returns a global HTTPS URL anyone can GET / POST / PUT / PATCH / DELETE against. The owner-only portal at
/webhook/<slug>shows every incoming request with method, headers, body, source IP, and timestamp.Configure the canned response status code (200 / 401 / 429 / 500) from the portal to simulate failure paths without redeploying anything.
Dispatch outbound HTTP requests
Open Request Sender from the account rail, compose a request (method, URL, headers, auth, body), and save it as a template for reuse. Every dispatch is logged with full response details for 8 hours.
Search with JMESPath
Open the search bar in the visualizer and type a JMESPath expression — for example,
users[?age > `30`].name. The tree filters live with match counts and Prev/Next navigation.Sync your workspace across devices
Cloud Backup is in Settings: manually back up your tabs, palette, and pane split, then restore them on any other signed-in browser. The Gemini API key (used for the AI Fix transport) stays local-only and is never synced.
Keyboard shortcuts
Every shortcut works on macOS (Cmd) and Windows / Linux (Ctrl); the ⌘ glyph is shown for compactness.
| Shortcut | Action |
|---|---|
| ⌘⇧F | Smart Format (full recovery) |
| ⌥⇧F | Simple Format (semantic preserve) |
| ⌥⇧C | Compress (minify) |
| ⌘⇧T | Cycle visualizer view (Tree / Graph / Table) |
| ⌘⇧H | Open the Webhooks dashboard |
| ⌘⇧D | Cycle to next color palette |
| ⌘Z | Atomic undo (text + format together) |
| ⌘F | Open Monaco's find widget |
Where to go next
Pick whichever surface matches what you came here for.