Question 1

How do I fix broken or malformed JSON online?

Accepted Answer

yellorn ships a 'Data Doctor' best-effort parser with 15 documented auto-fix passes for JSON: it strips markdown code fences, removes // and /* */ comments, normalizes Python literals (None/True/False), converts single quotes and unquoted keys, drops trailing commas, repairs missing commas, auto-closes truncated brackets, and more. Every fix is labelled in the status bar so you consent to every change before publishing.

Question 2

Can I clean up JSON returned by ChatGPT, Claude, or other LLMs?

Accepted Answer

Yes — paste the LLM response directly. yellorn auto-strips markdown ```json fences, removes inline comments, normalizes Python-style booleans (True → true, None → null), and recovers truncated payloads. The status bar shows exactly which fixes ran (e.g. 'Auto-fixed: markdown-code-blocks, trailing-commas, single-quotes') so the transformation is auditable.

Question 3

Does it repair broken XML, YAML, and CSV too?

Accepted Answer

Yes. The same recovery ladder runs across all four formats: 5 fixes for XML (markdown fences, BOM, missing brackets, auto-close-at-EOF, unescaped ampersands), 6 for YAML (BOM, fences, tabs-to-spaces, smart quotes, missing colon before block, unbalanced flow brackets), and 3 for CSV (BOM stripping for Excel-on-Windows exports, fences, smart quotes). Plus the JSON ladder, that's 29 documented fix classes total.

Question 4

How do I convert JSON to XML, YAML, or CSV (and back)?

Accepted Answer

Click the Convert menu in the editor toolbar. yellorn parses your input to a canonical value, asks the target plugin's checkConversion method whether the structure is faithfully serialisable, and either swaps the editor instantly or warns first ('Lossy: top-level array doesn't round-trip to XML — Convert anyway?'). All 12 cross-format pairs are supported, plus a Python-dict clipboard export from every format.

Question 5

Can I visualize JSON, XML, YAML, or CSV as an interactive tree, graph, or table?

Accepted Answer

Yes — three view modes ship: a virtualized tree (default for JSON/XML/YAML), a node-link graph powered by React Flow + Dagre layout, and a sortable table view (default for CSV). Each format declares which views it supports; the visualizer toolbar's ViewToggle filters automatically. Cmd+Shift+T cycles through the available views.

Question 6

Is there a JMESPath playground or query tool?

Accepted Answer

Yes. Type a JMESPath expression in the visualizer search bar (e.g. users[?age > `30`].name). yellorn evaluates the expression, swaps the effective tree to the matching nodes, shows match counts, and provides Prev/Next navigation. JMESPath ships as a 20 KiB lazy chunk that only loads when you first open the search bar.

Question 7

How can I publish a payload as a mock REST API or webhook?

Accepted Answer

Sign in (free), click Publish in the editor toolbar, and yellorn returns a globally distributed HTTPS URL. Anyone you share it with can GET / POST / PUT / PATCH / DELETE against the slug; you watch the request log fill in real time from the owner-only portal at /webhook/<slug>. Configure the canned response status code (200/401/429/500) to simulate failure paths without redeploying anything. Free tier: 5 active URLs, 24h TTL. Pro: 1,000/month with persistent URLs while subscribed.

Question 8

Can I compare two JSON files for differences?

Accepted Answer

Yes — yellorn's Compare Mode lets you select two tabs from the tab bar and run them through Monaco's read-only diff editor. JSON content is sorted before diffing for stable, semantically-meaningful output (key reorderings don't pollute the diff). Useful for API response regression, fixture consistency checks, and customer-payload triage.

Fix Broken JSON, XML, YAML, CSV — Mock Webhook APIs · yellorn

Data Doctor — repair broken structured data instantly

Cross-format converter — JSON ↔ XML ↔ YAML ↔ CSV

Mock webhook REST API — publish payloads as live endpoints

Multi-view visualizer + JMESPath search

Compare mode + smart format ladder