How to Import Contacts from a CSV File

Last updated May 4, 2026

PostKnock works with the customer list you already have. There's no integration to install, no scraper to set up — if your practice management system or CRM can export to CSV, you can use it. This guide covers the required column format, how to export from the most common practice management systems, what the import wizard does automatically, and how to handle deduplication and address validation.

Required CSV Columns

PostKnock needs six columns to mail a postcard. Header names are case-insensitive and the import wizard will auto-map common variants (FirstName, first_name, FIRST NAME all work).

  • first_name — recipient's first name. Used for personalization on the postcard ("Sarah, we miss you!").
  • last_name — recipient's last name. Used on the address block.
  • address1 — street address (e.g., "123 Main St"). Apartment/unit can go here or in address2.
  • city
  • state — two-letter abbreviation (CA, TX, NY). Full state names work too — PostKnock normalizes them.
  • zip — 5-digit or 9-digit ZIP. Leading zeros are preserved if you wrap the column in quotes.

Optional but useful columns:

  • phone — needed for follow-up call queues. E.164 (+15551234567), with-dashes (555-123-4567), or plain digits all work.
  • email — saved for future use; not used in MVP.
  • last_visit or last_appointment — ISO date or MM/DD/YYYY. Used to segment overdue patients.
  • tags — comma-separated tags for segmentation (e.g., "vip,recall,perio").

Tip: Don't worry about cleaning your CSV before upload. The wizard validates every row and surfaces errors so you can fix them in one place. Often it's faster to fix issues inside PostKnock than in Excel.

Exporting from Common Practice Management Systems

Almost every PMS has a "patient list" or "client list" report that can be exported to CSV. Here's where to find it in the most popular systems used by PostKnock customers.

Dentrix (Dental)

Open Office Manager → Letters & Custom Lists. Choose "Patient Report by Filter," set your filter (for example, "Last Visit Before [date]"), and pick "Export to Tab Delimited" or directly to CSV. Dentrix exports columns like Pat First Name, Pat Last Name, Pat Address, etc. The PostKnock auto-mapper handles these labels automatically.

ServiceTitan (HVAC, Plumbing, Pest Control)

Reports → Customer Reports → Customer List. Configure the columns you want (Name, Address, City, State, ZIP, Phone, Last Service Date), then click Export → CSV. ServiceTitan splits "Name" into "First Name" and "Last Name" automatically when you choose the appropriate columns.

ChiroTouch (Chiropractic)

Front Desk → Patient Manager → Search/Filter. Run the search for the segment you want, then use the "Export Patient List" toolbar option. Output is a CSV that includes mailing address fields ready for PostKnock.

AVImark (Veterinary)

Reports → Client Reports → Client Mailing List. Filter by last visit date or species, then export to CSV. AVImark labels owner first/last names separately, which the PostKnock importer auto-maps.

If your system isn't listed here, look for any report that produces a "client list," "patient list," or "mailing list" and exports to CSV or Excel. Excel files (.xlsx) need to be saved as CSV before upload — in Excel: File → Save As → CSV (Comma delimited).

The Import Wizard: Auto-Mapping

When you drop your CSV onto the import zone, PostKnock reads the first row of headers and tries to match each one to a known field. "First Name," "FirstName," "fname," and "first_name" all map to first_name. Address variants like "Address," "Street," "Street Address," and "Mailing Address" all map to address1.

Any column the wizard can't auto-map appears in a "Needs review" panel with a dropdown so you can pick the correct field manually — or skip it entirely if it's data PostKnock doesn't need (account number, balance, etc.). You don't have to delete those columns from your CSV; just leave them unmapped.

Address Validation

Every imported address is validated against the USPS database. There are three possible outcomes:

  • Verified — the address is deliverable as-is. The contact is ready to be mailed.
  • Corrected — PostKnock found a slight variant (typo, missing apartment number, wrong ZIP). The wizard shows you the correction before applying it — you can accept or reject each one.
  • Undeliverable — the address can't be matched to USPS records. These contacts are quarantined and not included in mailings until you fix them. You'll see a list with the original address and a free-text field to update.

Address validation typically catches 1–5% of contacts on a first import, depending on how clean your source data is. Cleaning these once saves you from paying to print undeliverable cards across every future campaign.

Deduplication

PostKnock automatically deduplicates contacts using a name-plus-address fingerprint. If you re-upload a CSV that contains the same person at the same address, the existing contact is updated rather than duplicated. This means you can refresh your contact list weekly or monthly without worrying about your patient appearing in five copies.

If a person has moved to a new address, PostKnock treats that as a new contact. If you want to merge them, the contact detail page has a manual merge option — or you can simply mark the old address as "do not contact."

Tips for a Smooth First Import

  • Start with a sample. If you have 5,000 patients, import 50 first to confirm the mapping looks right, then re-run with the full file.
  • Use UTF-8 encoding. If accented characters look garbled (María appears as María), re-save the CSV as UTF-8. Excel users: choose "CSV UTF-8" when saving.
  • Quote ZIP codes that start with zero. Otherwise Excel strips them and "01234" becomes "1234." Wrap the column in quotes or set its format to Text.
  • Don't include header rows in the data. The wizard expects exactly one header row at the top.

For a quick refresher on what to do after your contacts are in, see Getting Started with PostKnock and Multi-Wave Campaigns. If you're a dental office working through your first recall, our dental recall postcard guide walks through the messaging side end to end.

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