A multi-format Data Doctor and universal data-file viewer — 20 formats from JSON and CSV to Parquet, Excel, and AI model files — that doubles as a hosted mock-webhook REST API platform.
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.
Open 20 formats in one editor. Beyond JSON / CSV / YAML / XML, drop a binary file — Parquet, Apache Arrow, Excel, MessagePack, CBOR, Protobuf, BSON, gzip — or an AI model file (Safetensors, GGUF, ComfyUI PNG) and yellorn decodes it locally to a browsable JSON preview. No upload, no server round-trip.
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.
20 formats in one editor — paste text or drop a file. Binary files decode locally; nothing is uploaded to view it.
Edit, fix, convert, and visualize. Each ships its own best-effort recovery ladder.
JSON · JSON Lines (NDJSON) · XML · YAML · TOML · CSV · SQL · Python · Raw Text
Open and inspect — decoded locally in a worker to a browsable JSON preview, no upload.
Apache Parquet · Apache Arrow / Feather · Excel (xlsx / xlsm / xls) · MessagePack · CBOR · Protobuf · BSON · gzip
Read headers and embedded metadata without touching the multi-GB payload.
Safetensors (tensor header) · GGUF (llama.cpp model metadata) · ComfyUI (workflow from a generated PNG)
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.
Drop a .parquet, .arrow, .xlsx, .msgpack, .cbor, .pb, or .bson file and read it as a tree or sortable table — decoded locally, no upload. The viewer most online tools can't offer because the file never leaves your browser.
Check a .safetensors or .gguf header for tensor shapes, dtypes, and parameter count without downloading gigabytes of weights — or drop a ComfyUI PNG to recover its full prompt graph, checkpoint, LoRAs, and sampler settings.
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.