GAEB X83 vs. X84: Differences, Usage, and Common Mistakes

GAEB Formats in Context: The Procurement Process

To understand X83 and X84, you need to know the procurement process. The GAEB standard maps the entire workflow into file formats: X81 contains the bill of quantities without prices — the BoQ handover, for example from the planner to the awarding body. X82 is the cost quotation — a priced BoQ used before the formal bidding phase. X83 is the bid request — the unpriced BoQ the contracting authority issues to bidders. X84 is the bid submission — the bidder enters prices and returns the file. X85 carries side offers, X86 the contract award. Each format has a defined role in the process. X83 and X84 sit at the most critical point: the transition from price request to binding bid.

X83: The Bid Request

The X83 file is the bid request: the unpriced bill of quantities that the contracting authority provides via the e-procurement platform. The bidder imports the file into estimation or AVA software, checks structure and quantities, and enters unit prices. The structure of the BoQ is binding — positions may not be added or deleted. Technically, X83 is based on the GAEB DA XML 3.x standard — an XML schema that precisely defines the data structure.

X84: The Bid Submission

The X84 file is the electronic bid: the bill of quantities with the bidder's unit prices, total prices, and any surcharges. The bidder creates the X84 file from the received bid request (X83) and submits it via the procurement platform. The file is machine-readable and allows the authority to automatically compare prices across all received bids. The contract itself arrives later as an X86 file — the bidder doesn't create that one, they receive it.

The Most Common Mistakes in Practice

Mistake 1: Submitting the unpriced X83 instead of the priced X84. Happens more often than you'd think — especially when files get renamed. Contracting authorities reject incorrectly formatted submissions. Mistake 2: Creating the X84 with the wrong GAEB version. If the bid request is based on GAEB DA XML 3.3, the bid must also use this version. Version conflicts cause import errors. Mistake 3: Manually editing prices with a text editor. GAEB files should not be edited by hand. The XML structure is sensitive — one wrong character can make the entire file unusable. Mistake 4: Modifying items in the X84. The authority's bill of quantities is binding. Adding, deleting, or restructuring items leads to bid exclusion.

Older GAEB Formats: DA81, DA83, P83

Alongside the current XML formats (X81-X86), older GAEB versions still appear in practice. DA81 and DA83 are based on the older ASCII format (GAEB 90 / GAEB 2000). The phase logic is identical across all generations: D83 and P83 are the bid request of the older generations, and the priced return is submitted as D84 or P84 — the modern equivalent is X83/X84. Some contracting authorities and older AVA programs still use these formats. Modern software should handle both worlds — both the legacy DA formats and the current XML variants. When submitting bids: Always use the format specified by the contracting authority.

Analyzing GAEB Files Automatically

Regardless of format — whether X83, X84, DA83, or P83 — the real challenge isn't opening the file, but understanding its contents. Manually evaluating a bill of quantities with 500+ items takes hours. AI-powered analysis can accelerate the content evaluation: Which items are critical? Where are the risks? Are there missing items that are technically required? This works across formats — whether the BOQ comes as a GAEB file, PDF, or Word document.

Frequently Asked Questions