BLM Import Requirements

BLM is a standard UK property data feed format used to exchange listing information in bulk between systems, portals, and property software.

With ListProperty you can import hundreds of listings from a single file, export your portfolios when you need them elsewhere, and keep your inventory synchronized without manual data entry.

New to BLM? Read the full overview on our BLM Import & Export page.

To ensure successful imports, please follow these rules.

File Requirements

• File extension: .blm or .txt
• Maximum file size: 10 MB
• UTF-8 encoding recommended

Required Sections

Your file must contain all of these sections:

#DEFINITION#
#DATA#
#END#

Record Terminators and Column Separator

Every data row must end with `~`, and columns must be separated using `|`.

Required Fields

AGENT_REF

Required and used for updates, synchronization, and duplicate detection.

TRANS_TYPE

1 = Sale
2 = Rent

PRICE

Must be an integer value greater than or equal to zero.

SUMMARY

Must contain between 5 and 200 characters.

POSTCODE1 and POSTCODE2

Required and must form a valid UK postcode.

PROPERTY_TYPE

Must contain a supported property type code. Common examples:

3   Detached House
6   Flat / Apartment
116 Land

DESCRIPTION

Optional. If provided, it is truncated to a maximum of 2000 characters.

Images

Images are imported from `MEDIA_IMAGE_*` columns. For new listings, at least one valid image is required, otherwise the listing may be skipped.

Don't Have a BLM File?

If you already advertise elsewhere but do not have a BLM export ready, you can use blmconverter.com to build a feed from an existing property advert.

The tool can generate a compatible BLM file that you can import directly into ListProperty — useful when migrating stock without recreating every listing manually.

Need help with your BLM file?

If your file does not pass validation or you need help with import mapping, contact our team and include a short description of the issue. -> Go to the contact page.