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Dummy Data Generator

Build fictional test data for demos and development. Pick a type per column and export to CSV, TSV, JSON, JSON Lines, SQL INSERT or Excel. Names, addresses and companies are made-up combinations, and emails use only example domains.

On-device・No uploadMobile friendlyWorks offline

Your files and input are processed only inside your browser on this device and are never uploaded to our servers.

Templates
Language of personal data

1 to 100,000

The same seed and settings always give the same data.

Names, addresses and companies are made-up combinations (one can match a real person or company by chance). Emails use only example domains. Phone numbers aim at forms that do not exist, but that is not guaranteed. Postal codes only follow the format and do not match the address.

Columns0 / 50

No columns yet. Start from a template or the sample, or press “Add column”.

Output
Format

How to use

  1. Member columnsname, email, date

    Set columns and types

  2. 1,000 rowsseed 42

    Generate with rows and a seed

  3. members.sqlINSERT statements

    Save as CSV, JSON or SQL INSERT

Set the columns, choose the rows, then export CSV, JSON or SQL

  1. Press “Try the sample” or a template (members, orders, products) to get columns. “Add column” adds your own.

  2. Give each column a name and a type: sequence, UUID, integer or date ranges, choices, a pattern (e.g. ORD-\d{6}), a fixed value, or fictional names and addresses. You can leave a share empty or avoid duplicates.

  3. Set the number of rows (up to 100,000) and a seed. The same seed and settings always give the same data.

  4. Pick the output: CSV, TSV, JSON, JSON Lines, SQL INSERT or Excel. For CSV choose UTF-8 (BOM) or Shift_JIS; for SQL choose MySQL, PostgreSQL or SQLite, the table name and rows per statement.

  5. Check the 10-row preview, press “Generate with these settings” and download. Save the settings as JSON to load them next time.

What it does

Fictional data for Japan and English

Generates names (family, given, furigana), prefectures and cities, postal code formats, phone numbers and company names. Within a row, name, furigana and email come from the same person and prefecture, city and address from the same place, so they agree. English data (names, states, addresses, companies) is one switch away.

No real contact details

Emails use only the reserved example.com, example.jp and similar domains. Japanese phone numbers use unlikely-to-exist forms (03-0xxx-xxxx, 090-0000-xxxx, 0120-000-xxx), but Japan has no officially reserved fiction range, so they may match real numbers. English ones use 555-0100 to 0199, set aside for fiction in North America.

Reproducible with a seed

The same seed, settings and row count give the same data, and changing the row count never changes the first rows. A random seed gives a different set.

Six formats and SQL dialects

CSV (UTF-8 BOM, Shift_JIS), TSV, JSON, JSON Lines and Excel, plus INSERT statements for MySQL, PostgreSQL and SQLite. Table and column names are quoted per dialect and the “'” in strings (and “\” for MySQL) is escaped.

Regex-like patterns and saved settings

Write “[A-Z]{3}-\d{4}” or “(Tokyo|Osaka) office” to make product codes or employee IDs. Column settings can be saved as JSON and loaded again.

Use cases

  • Fill a development app or screen with members, orders and products
  • Create INSERT statements for a test database in MySQL, PostgreSQL or SQLite
  • Hand out CSV or Excel files for demos and training without real personal data
  • Make a 100,000-row CSV or JSON Lines file for performance tests
  • Fix the seed so every test run gets the same input data

Supported formats

Output

CSV (UTF-8 with BOM / UTF-8 / Shift_JIS)TSVJSONJSON LinesSQL INSERT (MySQL / PostgreSQL / SQLite)Excel (.xlsx)

Saved settings

JSON (saved by this tool)

Capability matrix

FeatureSupportNotes
Sequence, UUID, integer/decimal/date/date-time ranges, boolean, choices, pattern and fixed columnsSupported—
Fictional names, furigana, addresses, postal codes, phone numbers, emails and companies (Japanese and English)Supported—
Seed reproducibility, saving and loading settings as JSONSupported—
Output as CSV, TSV, JSON, JSON Lines, SQL INSERT and ExcelSupported—
Duplicate check within a columnPartial“Avoid duplicates” only checks within this run and re-draws up to 100 times, then reports an error. A database unique constraint is not guaranteed
Looking like real data or matching statistical distributionsNot supportedValues are picked evenly from ranges and lists; realism is not guaranteed
Relations between columns (total = price × quantity) or foreign-key consistencyNot supportedColumns are independent (only name/furigana/email and prefecture/city/address agree within a row)
Postal codes matching the address, or real street numbersNot supportedPostal codes only follow the format and street numbers are made up

Limits & notes

  • One run makes up to 100,000 rows, 50 columns and 2,000,000 cells (rows × columns). Excel output is limited to 500,000 cells.
  • Generation runs in a Web Worker with progress and a cancel button. More rows use more memory, so some devices need fewer rows.
  • Patterns support only characters, [a-z], \d, \w, (a|b), ?, {n} and {n,m}. Unbounded forms such as * and +, lookahead and back-references are not supported. Output is limited to 1,000 characters.
  • In CSV and TSV, text starting with = + - @ (fixed values, choices, patterns, column names) gets a leading ' so spreadsheets do not run it as a formula. Excel output keeps it as text.
  • Dates are YYYY-MM-DD from the year 1000; date-times go to the second, with no time zone. Decimals drop trailing zeros (1.50 → 1.5).
  • Furigana is hiragana for Japanese data and the romanised name for English data. Saved settings files up to 1 MB can be loaded.

Privacy & safety

Column settings, generation and export all happen in your browser. Your settings and data are never sent to or stored on a server.

FAQ

Can the test data contain a real person’s name or address?
Names, companies and addresses are made-up combinations of name and company parts. They are common name forms, so a result can match a real person or company by chance. Emails use only reserved domains such as example.com and reach no one.
Are the dummy phone numbers guaranteed not to exist?
Japanese numbers use unlikely forms (landlines with an exchange starting with 0, such as 03-0xxx-xxxx; mobile 090-0000-xxxx; toll-free 0120-000-xxx). Japan has no officially reserved fiction range, so they may match real numbers: use them for testing only and never dial them. English numbers use 555-0100 to 0199, reserved for fiction in North America.
Can I generate SQL INSERT statements?
Yes. Choose MySQL, PostgreSQL or SQLite, the table name and rows per statement (1–1000). Quotes in strings are escaped, and NULL, booleans and numbers follow the dialect.
How do I get the same data again?
Use the same seed, settings and column order. “Save settings as JSON” stores everything including the seed, and loading the file restores it.
Are unique values guaranteed?
A column marked “Avoid duplicates” re-draws a repeated value within this run and reports an error if 100 tries are not enough. Sequences never repeat. This is not a database unique constraint, and values already in your data are not checked.
Is the generated data uploaded?
No. Everything is processed in your browser and the data never leaves your device.

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Tick what to fix and clean up spaces, character widths, dates and numbers across a whole Excel or CSV file at once. Changed cells are highlighted, and you can save as Excel or CSV.

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SQLite Viewer & Query Playground

Drop a .sqlite or .db file to list its tables, views, indexes and triggers and browse rows with paging, sorting and filtering. Run multi-statement SQL in the editor, export results as CSV, Excel or JSON, and save the changed database as .sqlite. Your files never leave your device.

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DDL to ER Diagram & DB Docs

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No upload

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