Validate Email Addresses in Parquet Files Online
Validate email addresses in Parquet files directly in your browser. Add a boolean column flagging valid and invalid emails, or filter to show only invalid rows — no upload required.
How to validate Email Addresses in Parquet files
- Drop your file onto the upload area. It is loaded into the in-browser engine and the first 200 rows are shown.
- Choose the email column. The tool preselects the first column whose name contains "email" or "mail", otherwise the first column.
- Pick an action: Flag all rows adds an email_valid column (true or false), Keep invalid only returns the rows that fail, and Keep valid only returns the rows that pass.
- Click Validate Emails. The counts of valid and invalid addresses and the percentage invalid appear next to the result.
- Download the result in the same format you uploaded.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A conference exports its registration sheet before sending joining instructions. Some addresses were typed by hand at the desk, and one attendee left the field empty.
Input (Parquet)
Parquet file (binary, columnar) — shown as a table with its schema
| attendee | ticket | |
|---|---|---|
| Priya Nair | priya.nair@uni.edu | student |
| Jonas Weber | jonas.weber@firma | standard |
| Sam O'Neill | sam.o'neill@mail.ie | standard |
| Lucía Gómez | lucia.gomez@correo.es | speaker |
| Wei Chen | NULL | student |
| Tom Hart | TOM.HART@Example.CO.UK | standard |
Schema: attendee VARCHAR, email VARCHAR, ticket VARCHAR
Settings
- Email column: email
- Action: Flag all rows
Result
| attendee | ticket | email_valid | |
|---|---|---|---|
| Priya Nair | priya.nair@uni.edu | student | true |
| Jonas Weber | jonas.weber@firma | standard | false |
| Sam O'Neill | sam.o'neill@mail.ie | standard | false |
| Lucía Gómez | lucia.gomez@correo.es | speaker | true |
| Wei Chen | NULL | student | NULL |
| Tom Hart | TOM.HART@Example.CO.UK | standard | true |
Jonas's address has no dot and suffix after the domain, so it fails. Sam's address is legal under the email standard, but the apostrophe is outside the allowed character set, so it is flagged false. Upper case is fine. The empty cell gets no verdict. The summary reads 3 valid, 2 invalid (40.0% invalid), and Wei Chen is counted in neither.
Working with Parquet files
The chosen column is converted to text before matching, so any column type can be picked. Only a string column makes sense, though. A LIST column of addresses is turned into one string like [a@x.com, b@y.com], which always fails. Unnest it into one address per row with the SQL Query tool before validating. A struct column holding contact details needs the email field pulled out first.
In Flag mode, email_valid is added at the end of the schema as a BOOLEAN. Nulls stay null, so a later count of false values does not include missing addresses. The two Keep modes return the original schema with fewer rows, which suits a pipeline that should only pass well-formed addresses on to a mail system. Validation is purely pattern-based. No DNS lookups or network calls are made, so large files validate quickly in the browser. Dictionary-encoded string columns, common for repetitive values such as company domains, are read like any other text column.
Frequently Asked Questions
Can I validate a Parquet column that holds a list of emails?
Not as it is. The list is turned into a single string and fails the check. Unnest it into one address per row with the SQL Query tool first.
What type is email_valid in the Parquet output?
BOOLEAN, with null for rows where the email value was null.
What rule does the validator apply?
The whole value must be a local part of letters, digits and . _ % + -, then one @, then a domain of letters, digits, dots and hyphens ending in a dot and at least two letters. It is a practical format check, not a full RFC 5322 parser.
Can valid addresses be rejected, or bad ones accepted?
Yes, at the edges. Legal but unusual addresses fail, such as ones with an apostrophe, accented letters, quoted local parts or punycode endings like .xn--p1ai. A few malformed ones pass, such as those with two dots in a row. Review the invalid list before deleting anything.
Does it check that the mailbox exists?
No. Nothing is sent and no domain lookups are made. The check runs in your browser against the text only. Use a verification service if you need deliverability checks.
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