Frontend Development
UI, markup, styling, and client-side tools for interfaces that run in the browser.
Minify JSON Online — JSON to One Line
Minify JSON online to compact one-line JSON. Compare pretty vs minified size in the size panel — free browser JSON minifier, no signup.
Continue ReadingCompare JSON Online — JSON Diff Tool
Compare JSON online with a structural path-level JSON diff. Paste A and B, review added, removed, and changed values side by side — free, no signup.
Continue ReadingValidate JSON Online — Fix Syntax Errors Fast
Validate JSON online with clear line/column errors. Fix trailing commas and quotes in your browser — free JSON validator, no signup.
Continue ReadingJSONL to JSON — Convert JSON Lines Online
Convert JSONL (JSON Lines / NDJSON) to a JSON array online. Format, minify, or export — free in your browser.
Continue ReadingConvert JSON to XML Online (and XML to JSON)
Convert JSON to XML or XML to JSON online in your browser. Download the result — free converter, no signup.
Continue ReadingJSON Size Calculator — Bytes & Minify Savings
Calculate JSON size online: characters, UTF-8 bytes, pretty vs minified size, depth, and key counts — free in your browser.
Continue ReadingPython Dict to JSON Online — Free Converter
Convert a Python dictionary or list to JSON online. Supports True/False/None and single quotes as a best-effort paste converter — free in your browser.
Continue ReadingJSON Formatter Online — Pretty Print Free
Format and pretty-print JSON online in your browser. Minify, validate, download .json — free JSON formatter, no signup.
Continue ReadingTest Email with Mailpit, Docker & ngrok
Run Mailpit in Docker, expose it with ngrok, and send test emails from Email Viewer — verify From, Subject, and MIME headers without an ESP.
Continue ReadingOpen an EML File Online — Free
Open .eml files online to preview HTML email, convert to HTML, and export PNG or JPG — private in your browser, no Outlook required.
Continue ReadingConvert EML to PDF Online — Free
Convert an .eml file to PDF in your browser: import the message, preview the HTML, then export PDF — free, no upload, no signup.
Continue ReadingEML vs MSG: What's the Difference?
EML vs MSG explained — formats, Outlook vs other clients, when to save as .eml, and why ToolsViewer opens .eml but not Outlook .msg.
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