🇩🇪 German software • 100% offline • GDPR-compliant

Clean address data — automatic, accurate, no cloud

ListenFix uses fuzzy matching to find significantly more duplicates than Excel, normalizes postal codes and street names, and exports your list cleanly back to Excel or CSV — all on your own machine, without a single address leaving your office.

Try for freeHow it works
✓ No sign-up required✓ 14-day trial✓ Made in Germany

What dirty address data really costs you

In a mailing of 10,000 recipients a 5% error rate looks small — until you add up the postage. These four errors appear in virtually every uncleaned list:

7-12%
Duplicates Excel cannot find
Avg €850 per 10k mailing
3-5%
Wrong postal codes / abbreviated streets
Avg €420 in return costs
2-4%
Deceased recipients or movers
Avg €290 wasted postage
1-2%
GDPR violations (missing consent)
up to €20M fine

Mid-sized senders typically waste €1,500–€2,500 per mailing on poor address quality — money that two clicks could save.

What ListenFix does differently than Excel

ListenFix was built specifically for European address data — by a developer in Vorarlberg, Austria, who saw too many mailings fail because of preventable data errors.

🎯

Fuzzy matching, not exact-match

Excel finds only exact duplicates. ListenFix recognises "Smith" vs "Smyth", "Main St. 12" vs "Main Street 12", "Cologne" vs "Köln". Typical hit rate: 4-6× more duplicates.

🔒

100% offline & GDPR-compliant

Your address data never leaves your machine. No cloud, no server transfer, no data-processing agreement required. Works without internet.

📮

Auto-normalise postal codes & streets

Corrects abbreviations, detects outdated postal-code formats, harmonises spellings. Result: Deutsche Post / Austrian Post accepts your mailing as bulk-rate without rejection.

⚡

Excel/CSV in, Excel/CSV out

No new tool to learn. Open your existing list, let ListenFix clean it, save back. Cleaning 10,000 addresses takes under 60 seconds.

Before / After — a real example

Extract from a real customer list with typical issues:

Before (Excel list)
  • Müller, Hans · Hauptstr. 12 · 80331 München
  • Mueller, H. · Hauptstrasse 12 · 80331 Muenchen
  • Schmitt, Eva · Kölnerring 5 · 50667 Köln
  • Schmidt, Eva · Kölner Ring 5 · 50667 Coeln
  • Bauer, Peter · Marktpl 3 · 8033 München

5 entries — all "different" to Excel, in reality 3 people + 1 wrong postal code.

After (ListenFix output)
  • Müller, Hans · Hauptstraße 12 · 80331 München
  • Schmitt, Eva · Kölner Ring 5 · 50667 Köln
  • Bauer, Peter · Marktplatz 3 · 80331 München ⚠ postal code fixed

3 clean entries, 2 duplicates removed, 1 postal code flagged. Saving on a 10k mailing: ~€120.

How cleaning works in 3 steps

1

Open file

Drag your Excel or CSV file into ListenFix. Supports .xlsx, .xls and .csv with any delimiter.

2

Map columns

ListenFix usually detects first name / last name / street / postal code / city automatically. Otherwise: one click for manual mapping. Takes ~10 seconds.

3

Clean & export

Set fuzzy-matching threshold, click "Clean", review preview, export back to Excel/CSV. Original file is untouched.

Pricing

One-time purchase, lifetime use. No subscriptions, no cloud fees.

View all plans & trial options

Frequently asked questions about address-data cleaning

In typical customer lists ListenFix finds 4–6× more duplicates than Excel. Excel compares character by character; ListenFix uses fuzzy-matching algorithms (Levenshtein, Soundex) that also catch typos, alternative spellings and abbreviations. In a 10,000-row list that often means 400–700 additional duplicates detected.
Completely. ListenFix runs 100% locally on your machine — no cloud upload, no server connection, no internet traffic during cleaning. As a result no data-processing agreement (AVV / DPA) is required. The product satisfies GDPR Art. 32 (security of processing) by design.
Yes. ListenFix handles DACH address formats: 4-digit postal codes (AT, CH) and 5-digit (DE), regional spellings ("Gasse" / "Strasse" / "Straße"), special characters (ß, ö, ä, ü). The normaliser recognises Vienna, Zurich, Berlin alike.
Excel (.xlsx, .xls), CSV with all common delimiters (comma, semicolon, tab, pipe), and various encodings (UTF-8, Windows-1252, ISO-8859-1). Export keeps the original format — no format switching needed.
ListenFix is sold as a one-time purchase, no subscriptions. Exact prices and feature breakdown per plan are on our pricing page. A 14-day trial is available without sign-up — so you can verify on your own list that the tool cleans as expected before buying.
Yes. ListenFix handles lists with 500,000+ entries; performance depends on the machine. On a modern mid-range PC (8 GB RAM) cleaning 100,000 addresses takes around 3–5 minutes.

Try ListenFix with your own list

14 days free, no sign-up, no risk. If ListenFix does not find hidden duplicates in your specific list, you do not buy.

Download free now