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100% private · GDPR compliant · No uploads

Clean UK data in your browser

Phone numbers, postcodes, NI numbers, sort codes — validated instantly. Your data never leaves your device.

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7-day free trial · No card required · View pricing

Sound familiar?

Phone numbers in every format. Postcodes with no spaces. NI numbers in lowercase. One export from your CRM, another from a survey — same data, five different styles. Manually fixing it means find-and-replace, copy-paste, and hoping you didn’t miss a typo.

Another cloud tool?
GDPR paperwork?
No thanks!

That’s why we built Simple Data Cleaner. Select your information and it validates, normalises, and formats everything to UK standards.

Phones, postcodes, NI numbers, sort codes, bank accounts, emails, names
Invalid rows flagged in a report
Runs in your browser — no uploads, no cloud, no paperwork

The Solution

Your data today

07700900461Mobile
sw1a1aaPostcode
ab123456cNI number
1.2.3.4.5.6Sort code
12345678Bank account
user@example.com Email
dr john smithName

And you can’t just upload this anywhere. Postcodes, NI numbers, customer details — it’s sensitive.

After Simple Data Cleaner

+44 7700 900461Mobile
SW1A 1AAPostcode
AB 12 34 56 CNI number
12-34-56Sort code
12 34 56 78Bank account
user@example.comEmail
Dr John SmithName

All in your browser. No uploads, no cloud, no risk.

GDPR & privacy done right

Other tools upload your data to their servers. That means data processing agreements, extra paperwork, and risk. Simple Data Cleaner runs entirely in your browser — your files never leave your device.

  • We're not a data processor — no GDPR Article 28 paperwork
  • Zero uploads — sensitive PII stays on your machine
  • Full reports in-browser — audit trail without sending data anywhere

Click image to view larger

How it works

Three steps. Your data never leaves your device.

100% in your browser

  1. Upload

    CSV, Excel, or JSON. Your file stays on your computer.

  2. Select & clean

    Pick columns (phone, NI, postcode, sort code, email, names). Auto-detect available.

  3. Download

    Export CSV, Excel, or JSON. Full issues report included.

We validate

7 UK data types

Click one cleaned instantly

Phone numbers
NI numbers
Postcodes
Sort codes
Bank accounts
Emails
Name splitting

Try it now

Messy data in. Clean data out. Instant.

Phone NI Postcode Sort code Email

Result

—

100% in-browser. Nothing leaves your device.

Full rules

What you should know

Everything you need in one place.

Is my data private?

Yes, 100% private. All data processing happens in your browser — your files never leave your device. No servers, no databases, no third parties can access your data.

What UK data formats can I validate?

UK phone numbers (mobile and landline), National Insurance numbers, postcodes, bank sort codes and account numbers, email addresses, and name splitting. All validation follows official UK standards.

Is it GDPR compliant?

Yes. Because all processing happens in your browser, we are not a data processor under GDPR. Your data never leaves your device.

What file formats are supported?

Upload CSV, Excel (XLSX/XLS), or JSON. Export cleaned data in CSV, Excel, or JSON.

Start free trial Pricing

What you get when you upload

Beyond UK validation — duplicates, whitespace, export formats, and detailed reports. All in your browser.

Duplicate removal

Detect exact duplicate rows, preview before export, optionally remove on download.

Whitespace cleaning

Trim spaces, normalize formatting across all columns automatically.

Export your way

CSV, Excel, or JSON — regardless of upload format. Include an issues column if you need it.

Detailed reports

HTML reports for issues, cleaned data, and preview — exportable, shareable, UK-standard explanations.

View sample reports

Try it with sample data — no signup

Upload our pre-built test file and run through the full workflow. Validate UK data, see the issues report, preview cleaned results, and export — exactly what you'd get with your own files.

  • Pre-loaded test file — phones, NI numbers, postcodes, and more
  • Full HTML reports — issues, cleaned data preview, audit trail. See samples
  • Export CSV or Excel — same output you'd get with your own data
Open the example
Try with Example Data — load sample UK data to try the tool in your browser, 100% private & secure

What you'll see when you try the example
Bespoke Data Cleaning

Need specialist rules for internal data?

We partner with compliance, ops, and data teams to build in-browser validation for bespoke fields — from region_description to staff_employee_number and beyond. Share your edge cases and we'll deliver tailor-made rules that run entirely in your users' browsers, keeping sensitive records on-premise and fully GDPR aligned.

  • Custom validators for proprietary fields and internal reference codes
  • Browser-based deployment ensures zero data leaves your environment
  • Direct collaboration with your domain experts to codify complex rules

How the bespoke process works

  1. 1. Discovery workshop Share the fields, sample data, and desired outcomes. We map the validation flow together.
  2. 2. Prototype & testing We build tailored rules inside our client-side engine and iterate with your team.
  3. 3. Deployment & handover Validated rules are shipped into your Simple Data Cleaner workspace with full documentation.
Book a discovery call Learn more about our approach