What is the CSV Mock Data Generator?

The CSV Mock Data Generator is a browser-based developer tool that builds realistic CSV test data with a visual field and rule builder. Instead of hand-writing a schema, you add columns and pick one of seven generation rules for each field. Faker.js powers realistic values, and the engine converts the result to RFC 4180-compliant CSV — no backend, no signup, no uploads.

Features

• Visual field/rule builder: Add columns and assign a rule to each one — no schema syntax required
• Seven rule types: Faker, Constant, Sequence, Weighted, Lookup, Expression, and Function rules cover nearly any mock-data need
• JSON Schema import: Import a JSON Schema and the builder maps each property to a field automatically
• Template mode: Prefer code? Switch to template mode and describe fields as a JSON object with {{faker.*}} hints
• RFC 4180-compliant CSV: Correct comma, quote, and newline escaping out of the box
• Deterministic seeding: Same input + seed = identical output, ideal for reproducible test suites
• Multi-locale support: Generate localized data in 35 locales
• Bulk generation: Produce up to 10,000 rows
• Copy & download: One-click copy to clipboard or download as .csv

Use Cases

• Database seeding: Import the CSV directly into PostgreSQL, MySQL, or SQLite
• Spreadsheet testing: Populate Excel or Google Sheets with realistic rows
• Data pipeline testing: Feed CSV into ETL processes and data workflows
• Load testing: Generate bulk CSV for performance benchmarks
• Demo environments: Quick CSV datasets for presentations

How It Works

1. Add fields. Use the visual builder to add columns. For each column, choose a rule.
2. Configure rules. Pick Faker for realistic values, Constant for fixed text, Sequence for IDs, Weighted for probability splits, Lookup to reference another column, Expression for computed values, or Function for custom logic.
3. Set count, locale, and seed. Choose how many rows, the locale, and an optional seed for repeatable output.
4. Generate & export. The output renders as RFC 4180 CSV. Copy it or download the .csv file.

Nested objects and arrays are serialized as JSON strings inside each cell, so every row stays a single flat line.

Rule Types

• Faker — realistic values via Faker.js (names, emails, addresses, and more)
• Constant — a fixed value that never changes between rows
• Sequence — auto-incrementing IDs and counters for primary keys and ordering
• Weighted — probability distributions, e.g. 80% active / 20% paused
• Lookup — pull values from other generated columns to keep rows consistent
• Expression — computed values using JSONata expressions
• Function — custom generator logic for anything else

Frequently Asked Questions

Is my data sent to a server?

No. All generation happens entirely in your browser using Faker.js. Your data never leaves your computer.

How are nested objects handled in CSV?

Nested objects and arrays are serialized as JSON strings inside the CSV cell. For flat data structures, each top-level field becomes a column.

What CSV format is used?

RFC 4180. Values containing commas, quotes, or newlines are wrapped in double quotes. Quotes inside values are escaped with "".

Can I reproduce the same output?

Yes. Set a seed value and the same fields, seed, and locale will always produce identical output.

How many rows can I generate?

Up to 10,000 rows per request.

Can I import an existing JSON Schema?

Yes. Import a JSON Schema and the builder maps each property to a field, which you can then refine with rules.

Related Tools

• JSON Mock Data Generator — The same builder, exported as JSON
• JSON to CSV — Convert an existing JSON array to CSV
• JSON Formatter — Pretty-print and validate your data