A multi-format Data Doctor that doubles as a hosted mock-webhook REST API platform — built for developers who paste broken structured data ten times a day.
Three capabilities define what Yellorn is, ordered by what makes a user say yes.
29 documented auto-fix passes recover broken JSON, XML, YAML, and CSV. Paste from ChatGPT, Excel exports, or truncated server logs — markdown fences, trailing commas, smart quotes, BOMs, and Python literals are all repaired. Every fix is labelled in the status bar; nothing is silently re-shaped.
Click Publish in the editor and any structured payload becomes a globally distributed HTTPS endpoint in 60 seconds. The slug URL accepts every HTTP method; the request log only the publisher can see. Configurable response status code (200 / 401 / 429 / 500) for failure-path simulation.
Convert across JSON, XML, YAML, CSV, and Python with a single click. Lossy boundaries surface a confirmation toast before re-shaping (e.g. CSV ← deeply-nested JSON). Atomic undo: one Cmd+Z reverts both the text and the active format.
Smaller features that turn the trio into a daily-driver workbench.
Tree (virtualized via react-window), Graph (React Flow + Dagre layout in a worker), and Table (sortable headers, cell edit, copy column / row). Each format declares which views it supports.
Type `users[?age > `30`].name` in the search bar and the tree filters live with match counts and Prev/Next navigation. The 20 KiB jmespath chunk only loads when the search bar opens.
Compose and dispatch GET / POST / PUT / PATCH / DELETE / HEAD / OPTIONS requests directly from the browser. Save templates for reuse. SSRF protection and a loop guard prevent abuse.
Smart (full recovery) → Simple (semantic preserve) → Safe (layout-only) → Compress (minify). Each format implements its own ladder; the status bar shows which tier ran.
What people actually paste into Yellorn — and the specific repair / publish path that solves it.
Paste JSON returned by ChatGPT or Claude. Markdown fences and explanatory comments are stripped automatically; Python-style None / True / False are normalised; smart quotes from rich-text pastes are replaced.
Point Stripe / GitHub / Polar / Slack at a yellorn URL while you build. Watch the request log fill in real time; copy any payload back into the editor for fast iteration.
Per-environment URLs with configurable response status codes — exercise your client's failure paths without redeploying anything.
Paste broken JSON from a Zendesk ticket or a server log. The recovery hints show what the customer actually meant before you write a fix.
UTF-8-BOM CSVs from Excel, smart-quoted YAML from Word templates, tab-indented YAML from auto-formatters — all repaired transparently.
Open the editor, paste a payload, and try Smart Format. Sign-in is optional until you publish a webhook.