Auto-margin Documentation

Last updated: May 5, 2026

Documentation

Uploading files

Which file types we accept for vehicle lists, which we refuse, and why the list of refusals is as long as it is.

Why we are strict

Every file you send us arrives from a third party — a supplier, a trader, a marketplace export, a forwarded email. That is exactly the path attackers use to reach dealer systems, and a stock list is an unusually convincing disguise. Nobody thinks twice about opening a spreadsheet from a supplier.

So we accept a deliberately small set of formats. If a format can carry code, hide its contents, or cannot be inspected, we refuse it — even when the specific file is certainly harmless. Keeping the list short is what makes it enforceable.

How an uploaded file is handledA file you upload is checked for its type, its size and its contents. Files that pass are parsed into your stock list. Files that fail are rejected and deleted, and you are told which check failed.Your fileType, size andParsed into your stock listRejected and deleted.csv · .xlsx · .pdfcontent checksYou see it in the platformYou are told which check failed

What we accept

FormatExtensionNotes
Comma-separated values.csvPreferred. Smallest, fastest to process, nothing hidden inside it.
Excel workbook.xlsxThe modern Excel format. Must not contain macros.
OpenDocument spreadsheet.odsLibreOffice and OpenOffice exports.
Portable document.pdfDealer offer sheets and printed stock lists.
Plain text.txtTab- or semicolon-separated exports from older DMS systems.

Files are accepted up to 25 MB each. If your export is larger than that, it is almost always because it contains images — export again without them, or split the list.

What we do not accept

The list below is long on purpose. Most of these formats are years or decades past the point where anyone should still be sending them, and several are refused precisely because they are obsolete: little modern tooling can safely inspect them any more.

Macro-enabled Office files

These formats exist specifically to carry executable code. A macro runs as soon as someone enables content, which makes them the most common delivery method for office-targeted malware. There is no version of a car list that needs a macro.

.xlsm.xlsb.xltm.docm.dotm.pptm.potm

Legacy Office binaries

The pre-2007 OLE2 container hides embedded objects and streams that are hard to inspect reliably. It has a long history of parser vulnerabilities, and modern tooling has largely stopped hardening it. Open the file and re-save it as .xlsx or .csv.

.xls.xlt.xlw.doc.dot.ppt.pps

Legacy and obscure spreadsheet formats

Formats from the Lotus, Quattro Pro and dBase era, plus interchange formats that predate any security model. SYLK in particular is still actively abused because it executes commands while looking like a harmless text file.

.slk.dif.wk1.wk3.wk4.wks.123.wq1.qpw.dbf.prn.sxc.xlr.wb2

Executables, installers and scripts

Nothing in this category is a vehicle list. If one arrives, it is either a mistake or an attack, and we treat both the same way.

.exe.msi.bat.cmd.com.scr.pif.vbs.vbe.js.jse.wsf.wsh.ps1.psm1.hta.jar.apk.app.sh

Archives and disk images

An archive hides its contents until it is opened, can be crafted to expand into far more data than it claims, and can be encrypted so that nothing can inspect it. Send the spreadsheet itself rather than a container holding it.

.zip.rar.7z.tar.gz.tgz.bz2.cab.arj.lzh.iso.img.vhd.dmg

Shortcuts, registry and help containers

These look inert and are not. Each one can point at or carry something that runs on the machine that opens it.

.lnk.url.reg.chm.hlp.inf.scf

Markup and vector formats that can carry script

HTML and SVG can both embed JavaScript, and RTF has been the vehicle for a long series of document exploits. If your export produces one of these, convert it before sending.

.html.htm.mht.mhtml.svg.xml.rtf

Encrypted or password-protected files

A file we cannot open is a file we cannot check. This applies even when the password is sent separately, and it applies to protected .xlsx and .pdf files as well as encrypted archives.

Renaming a file does not help

We check what a file actually is, not what it is called. Renaming stock.xlsm to stock.xlsx gets it refused at the same step, and renaming an archive to .csv gets it refused faster. If your system can only export a format we refuse, open it once and save a clean copy as .csv or .xlsx.

A note on spreadsheet formulas

A cell that begins with =, +, - or @ is treated as a formula by Excel, and a hostile one can run a command on whoever opens the file. This is worth knowing in both directions: we neutralise those cells on the way in, and you should be wary of any supplier list you open directly rather than through the platform.

Before you upload

  • One list per file. Combined workbooks are harder to reconcile.
  • Keep the header row. Column names are how we map your fields, and a list without them takes longer to onboard.
  • Remove password protection. A protected file is refused even if you send the password.
  • Send the file itself, not a zipped copy of it, and not a screenshot of it.

If a file is rejected

You will be told which check the file failed, so you can fix it and send it again. Rejected files are not stored, not opened, and not forwarded to anyone — they are discarded at the point of refusal.

If you believe a file was refused wrongly, or your system can only produce a format that is not on the accepted list, contact us and we will work out an ingestion route that does not require you to change your process.