Data & Test Data
Convert and format data such as JSON, CSV and YAML, and generate dummy data for testing. Prepare the data you need for development checks on the spot.
11 tools・Ordered by measured page views over the last 90 days.
Japanese Phone Number Generator
Randomly generate Japanese phone numbers (mobile, landline, toll-free). Hyphen on/off and CSV export.
Test Data Generator
Generate fictional test data — names, emails, phones, addresses, UUIDs — by count and columns. Export as CSV/TSV/JSON/SQL.
Japanese Name Generator
Randomly generate Japanese full names with furigana and romaji. Export sample names as test data by count to CSV.
JSON Formatter & Validator
Paste JSON to pretty-print or minify. Syntax errors are reported with line and column.
Japanese Address Generator
Randomly generate Japanese addresses (postal code, prefecture, city, block, building). Export as CSV for form checks.
CSV ⇄ JSON Converter
Convert between CSV and a JSON array, with header and delimiter options.
JSON Diff
Deep-compare two JSON documents and see added, removed, and changed keys with paths like a.b[2], color-coded. Key order is ignored; nesting is compared recursively.
Placeholder Image Generator
Create mockup placeholder images with a custom size, background and text colour. Save as PNG, JPEG or WebP.
Random Date Generator
Generate random dates for test data from a chosen range, count and format. Sorting and duplicate removal included.
YAML / JSON Converter
Convert between YAML and JSON in both directions. Syntax errors are shown with line and column numbers, and the indent width is selectable.
Email Address Generator
Randomly generate dummy email addresses for testing using safe reserved domains like example.com. Export to CSV.