What is a CSV File?

A CSV file (Comma-Separated Values) is a plain text file that stores tabular data. Think of it as a simple spreadsheet saved as text. Each line represents a row, and commas separate the values in each column.

For example, a CSV file containing customer data might look like this:

Name,Email,Age
John Doe,john@example.com,28
Jane Smith,jane@example.com,34

The first row contains headers (Name, Email, Age), and each subsequent row contains data for one customer. When you open this file in Excel or Google Sheets, it displays as a proper table.

CSV files are one of the most common data formats because they're simple, universal, and human-readable. Almost every software platform can export data as CSV—from Shopify and Stripe to Google Analytics and QuickBooks.

The simplicity of CSV makes it perfect for moving data between different systems that might not otherwise be compatible.

CSV files follow a simple structure:

1. Headers (first row): Column names that describe what each field contains 2. Data rows: Each line after the header represents one record 3. Commas: Separate individual values within a row 4. Line breaks: Separate rows from each other

Most spreadsheet applications hide this underlying structure and display CSV files as tables, but the file itself is just plain text.

While CSV files are simple, they're easy to mess up:

- Empty rows and columns from deleted data - Inconsistent formatting like mixed date formats - Hidden whitespace causing matching errors - Duplicate entries from multiple imports - Special characters breaking the comma structure

These issues cause import failures, broken formulas, and data quality problems. That's why cleaning CSV files before importing them is so important.