List Clean · One-time service
Clean a mailing list
before you print it.
A mailing list collects errors between sends: typos, moves, the same household twice. Upload a CSV; every address comes back standardized to USPS format.
Price, once
- Up to 500 rows
- 3.8¢ a row
- $19
- Up to 2,500 rows
- 1.9¢ a row
- $47
- Up to 10,000 rows
- 1¢ a row
- $97
- Address Quality Report, added to any run see a sample
- $29
No account. You see the diagnosis before you pay, results usually arrive in under 10 minutes, and a reply to the receipt gets a refund. A First-Class stamp is 82¢, so a full 10,000-row run at 1¢ an address has paid for itself by the 119th returned envelope it prevents.
Need USPS delivery-point verification on every row? The API returns it on a free key, and you can ask us to run a file through it as a service.
Step 1 · UploadCSV · ≤10,000 rows
The diagnosis is free. You see what the run will fix in your file before you pay.
Step 2 · Your file's diagnosis
Clean my listSecure checkout via Stripe. Results usually arrive in under 10 minutes. If the file does not help, reply to the receipt and we refund it.
Processing
Payment received. Your file is running now, and this page updates itself.
What one row becomes
A business in San Francisco filed its address with a misspelled street and a suite number.
As filed
2261 MARKET SREET # 22288 SAN FRANCISCO CA 94114
Returned
2261 MARKET ST SAN FRANCISCO CA 94114
- Match
- Exact, against the national address file
- Coordinate
- 37.76473, -122.43221, street interpolated
- Census tract
- 020300, county 06075
- Same address as
- 268 other filings (2261 Market St), group D1
- Median household income
- $182,547, 2024 five-year
- Tract
- 3,419 residents, 7.6% of homes vacant
Parse split the suite number off the street. Standardize matched the street through the misspelling and wrote it in delivery form. Geocode placed it and named how. Deduplicate found the 115 spellings of this address on the standardized form and put them in one group. Account counted the row exactly once.
Headers carrying a BOM, semicolon and tab exports, quoted commas and stray whitespace are handled on the way in.
The workbook
Your columns come back untouched and thirteen are appended to each row. Three real filings at one address, below.
| row | street | city | state | zip | standardized | match | match_type | longitude | latitude | coord_source | county_fips | census_tract | median_hh_income | tract_population | tract_vacancy_pct | dupe_group | dupe_of_row |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2261 Market St | San Francisco | CA | 94114 | 2261 MARKET ST, SAN FRANCISCO, CA, 94114 | Match | Exact | -122.43221 | 37.76473 | street_interpolated | 06075 | 020300 | 182,547 | 3,419 | 7.6 | D1 | |
| 2 | 2261 Market St Ste 80070 | San Francisco | CA | 94114 | 2261 MARKET ST, SAN FRANCISCO, CA, 94114 | Match | Exact | -122.43221 | 37.76473 | street_interpolated | 06075 | 020300 | 182,547 | 3,419 | 7.6 | D1 | 1 |
| 3 | 2261 Market Sreet # 22288 | San Francisco | CA | 94114 | 2261 MARKET ST, SAN FRANCISCO, CA, 94114 | Match | Exact | -122.43221 | 37.76473 | street_interpolated | 06075 | 020300 | 182,547 | 3,419 | 7.6 | D1 | 1 |
The appended columns: the standardized form and how it matched, the coordinate and how it was placed, county and tract, the tract's median household income, population and vacancy from the ACS 5-year survey, and the duplicate group with the row it repeats.
Rows that did not match keep their original values and are listed in the report with the reason. Where the federal address database covers the state, the point moves from the street to the structure and the row says so.
The report
The Address Quality Report is a printed file. Two of its pages, from the sample file, exactly as the report renders them.
Page 1, the cover
Section 8, what the bad records cost
Inside: one health score for the whole list, match quality, ZIP completeness, duplicate clusters, county concentration, a neighborhood income and vacancy profile, a re-run date, and what the undeliverable rows cost at your postage.
San Francisco, 10,000 addresses, 2.7 minutes
San Francisco publishes its registered business locations. We took the file exactly as filed and ran the five passes once, on August 18, 2026.
The arithmetic
A First-Class stamp is 82¢ before printing. On a 10,000-piece run, 4% to 8% of rows are typically undeliverable or duplicated.
That is $328 to $656 of postage on mail that cannot arrive. One pass costs $97, once, and pays for itself at the 119th bad row.
Cleaning a list before every send? The API runs the same checks at the point of entry, as each address is captured.
Questions
Is this CASS-certified DPV verification?
No. List Clean standardizes each row against the Census Bureau's national address database and reports how that row matched. CASS and DPV are two USPS programs: one certifies the software that codes an address into postal format, and the other confirms that a specific delivery point, down to the apartment, is one the USPS delivers to today. RevAddress is not a CASS-certified vendor, and List Clean does not run DPV. DPV runs through the API, on a free key, and a file usually needs this standardization pass first regardless, because DPV cannot restore a stripped ZIP code or find a duplicate household.
Does it update addresses for people who moved?
No. Updating an address after someone moves is NCOA, the USPS National Change of Address service, which is licensed separately and has its own paperwork. List Clean makes a file ready for that step. NCOA processors want standardized, deduplicated input, and every duplicate collapsed here is a record you do not pay them to process. Run this pass first and the NCOA run costs less and matches better.
What does the match report tell me?
Each row comes back marked Exact, Non_Exact, or no match. Exact means the address matched the national address database as you sent it. Non_Exact means it matched after standardization, which is where a misspelled street name or a missing directional gets repaired. A row with no match is listed in the report with the reason and keeps its original values, so the row you uploaded is still there. The category totals add up to the rows in your file.
Do I need an account?
No. Upload the file, read the free diagnosis, and pay only if you want the run. The download link goes to the email you enter at checkout, and it stays on this page while the job is running. Results usually arrive in under 10 minutes.
What happens to my file?
Your file is processed for your job and nothing else. It is never used for training, never resold, and never combined with anyone else's data. Files and results are deleted 30 days after the run, on a schedule that runs on its own. To have yours deleted sooner, reply to your receipt and ask.
What formats work?
CSV up to 8 MB and 10,000 rows. Commas, semicolons and tabs all work, with or without the hidden BOM a spreadsheet adds. Use headers like street, city, state, zip, where many spellings are recognized, or a single full_address column. An .xlsx upload is refused with a message asking you to save the sheet as CSV first. For a larger file, ask us and we will run it as a service.
What if the results are bad?
Reply to the receipt email and say what went wrong. Engineering reads it the same day and issues the refund on request. The match report is the first thing in the workbook, so you can judge the result within a minute of opening the file.