How to Buy LEGO Parts Using XML or CSV Files

When you purchase building instructions for a custom LEGO model (often called a MOC or My Own Creation) you usually receive a parts list file alongside the PDF guide. That file, in XML or CSV format, contains everything you need to source the bricks yourself: part numbers, quantities, and colours. This guide walks you through exactly how to use it across every major platform, from LEGO's own store to budget-friendly compatible alternatives. All Bobby Brix premium building instructions include both XML and CSV files as standard.

What Are XML and CSV Parts Files?

Both formats serve the same purpose: giving you a complete, machine-readable list of every part in a LEGO MOC so you can import it into a parts marketplace and build a cart or wishlist automatically, without manually searching for each brick one by one.

XML files are formatted specifically for BrickLink's catalogue system and include exact LEGO part IDs, colour codes, and quantities. CSV files are spreadsheet-style lists that have become increasingly widely supported. LEGO officially added CSV upload to Pick a Brick in 2025, making them the more versatile format for newer platforms. When in doubt, use the XML on BrickLink and the CSV everywhere else.

Option 1: LEGO Pick a Brick (Official)

URL: lego.com/pick-and-build/pick-a-brick

Use LEGO's own part-ordering service. Every brick here is brand new, 100% official LEGO, and shipped directly by the company from one of their factories from around the world. As of 2025, LEGO officially supports CSV file uploads, making it possible to import your full parts list directly without searching manually.

How to use CSV on Pick a Brick:

1. Go to the Pick a Brick homepage and click Upload List.
2. Upload the CSV file of the LEGO MOC you want to build.
3. The system automatically loads matching parts and flags which ones are in stock.
4. Review the results: verify quantities and availability before adding to cart.
5. Add available parts to your cart and complete checkout. Use BrickLink or Brick Owl for any parts that are missing or out of stock.

Option 2: BrickLink (Best for XML)

URL: bricklink.com

BrickLink is the world's largest online LEGO marketplace, owned by the LEGO Group but operated independently. It connects thousands of independent sellers offering both new and used LEGO parts, and it has the most complete parts catalogue of any platform, including rare, retired, and out-of-production elements that simply aren't available anywhere else.

How to use XML on BrickLink:

1. Log in to your BrickLink account (free to create).
2. Go to Account → My Wanted List → Upload → Upload BrickLink XML format.
3. Open the XML file on your computer, select all the content, and copy it.
4. Paste the entire XML contents into the box on the page and click Add to Wanted List. Name it something memorable like "My MOC Parts".
5. Go to Buy → Buy All to let BrickLink find the best combination of stores for your list.
6. Review sellers, shipping fees, and totals before finalising your orders.

Important: When importing a parts list, BrickLink defaults to condition "Any" — meaning both used and new parts will be suggested. To get new parts only, select all items in your Wanted List and change the condition to "New" before proceeding to Buy All.

Option 3: Brick Owl

URL: brickowl.com

Brick Owl is a well-established LEGO marketplace often recommended as a more modern, user-friendly alternative to BrickLink. It supports both BrickLink XML and CSV imports, has a clean interface, and offers solid price-comparison tools across stores. It's a strong option if you find BrickLink's interface dated or want a second opinion on pricing.

How to use XML on Brick Owl:

1. Create a free Brick Owl account.
2. Go to Wishlist → Import → BrickLink XML.
3. Upload your XML parts list and review the results.
4. Use the bulk-buy tool to add all available items to your cart, filtering by seller location for best shipping rates.

Important: As with BrickLink, Brick Owl defaults to condition "Any" on import. Change all parts to "New" in your wishlist before proceeding if you want new bricks only.

Option 4: Brickwith — formerly Webrick (GoBricks — Budget-Friendly)

URL: brickwith.com

Webrick, the popular "LEGO-compatible" brick supplier and official direct channel for GoBricks, has fully migrated to a new platform called Brickwith (brickwith.com) as of April 2026. The old Webrick parts service closes on 1 June 2026, so brickwith.com is now the correct address. Note that Webrick and Brickwith are separate platforms! Existing Webrick Wanted Lists are not carried over, but the new site's Part List feature handles imports with the same ease.

Brickwith sells "LEGO-compatible" bricks manufactured by GoBricks, not official LEGO, but high quality, fully compatible, and significantly cheaper. As the exclusive factory-direct channel for GoBricks, Brickwith guarantees availability across its full catalogue with no out-of-stock items. It's the fastest and most cost-effective option for building large MOCs where official LEGO parts would be prohibitively expensive.

How to use on Brickwith:

1. Go to brickwith.com and find the Part List import section.
2. Upload your CSV file. The platform will match compatible parts and flag any substitutions automatically.
3. Review the results and confirm substitutes are structurally acceptable for your build.
4. Add everything to your cart and order in a single shipment.

If you already use GoBricks-compatible bricks and are comfortable with non-LEGO parts, this is the most straightforward and economical option for building a full MOC from scratch. Check out or try the Bobby Brix GoBricks MOC Kits to test out the quality of Gobricks before committing to buying them yourselve!

Final Tips & Which Option to Choose

No single platform is right for every build. Here's a quick decision guide based on what matters most to you:

A few additional tips worth keeping in mind for any platform:

1. Always double-check colour codes when using CSV files, as colour naming conventions differ slightly between platforms.
2. Buy a small buffer of spare bricks for any parts used heavily in the build, losing a tiny piece mid-build is far more frustrating than having a few extras. 

And if you're only missing a handful of rare parts after your main order, combining platforms is often the most sensible approach: common parts from LEGO or Brickwith, rare elements from BrickLink.

All Bobby Brix premium building instructions include both XML and CSV parts lists as standard, ready to upload to any of the platforms above.

If you're new to MOC building and want to understand scale and dimensions before you start sourcing parts, the Bobby Brix Scale Converter and Scale Wizard are free tools that can help you plan your build before you spend anything.

Last updated: May 2026. Platform features and URLs are subject to change. Webrick.com parts service closes 1 June 2026 — use brickwith.com going forward.