SIP-36: LAND Estate Sales

TL;DR

What	In order to solve the current issue of LAND owners only being able to transact individual pieces of LAND estates, we are proposing to implement a solution based on GBM’s already existing bid-to-earn auction system.
Why	This will meet a long-identified need (discussion here) of the community and permit more flexibility in options for selling LAND and facilitate different kinds of transactions.
How	An approximate 8 week development program plus completion of a security audit. Existing technology will be leveraged.
When	Q1 2026
Who	GBM have developed several projects successfully with The Sandbox before and have proven themselves as a partner through running several successful auctions, the technology for which they are able to leverage to expedite delivery here. They continue to work with The Sandbox and so this supports aligned deliverables. They also have extensive experience in the broader Web3 space.

Council Recommandation

Neutral

SIP Details

Problem Description

There is currently no mechanism to permit LAND owners to sell LAND in estates. They can currently only sell individual units of LAND without any sort of bundling.

Solution Proposed

This Scope of Work outlines the development of a third party solution for secondary sales with integrated functionality for bundling LAND assets natively. This has been something your community has requested so they can trade their estates. The goal is to create a seamless and user-friendly experience within the existing GBM x The Sandbox dApp, ensuring scalability, performance, and maintainability.

The GBM team will handle the entire build and deployment, and the project is forecasted to take 8 weeks of total development time. Based on availability and technical requirements, we are therefore planning delivery in Q1 2026. We have estimated the cost to be $60,000.

Deliverables Of Final Product

• The Sandbox users will be able to access the existing GBM x The Sandbox dApp, where a new “Secondary Marketplace” tab will be added. This unified interface will allow all traffic to be directed through one destination, enabling the primary auctions and secondary markets to complement and support each other.
• Users will be able to list individual 1x1 LANDs directly on the secondary marketplace.
• For estate listings, users will have the ability to bundle multiple LANDs natively within the dApp before putting them up for sale. This will enable the trustless, single-transaction sale of estates - solving a key limitation of the current system.
• The bundling tool will be designed to only allow LANDs from the same estate to be grouped. If a user attempts to bundle unrelated LANDs, the system will display an explanatory error message and prevent the action.
• Given that there is no official estate API, the GBM team will make its own custom solution to detect if lands are part of an estate.
• The system will automatically generate an image and metadata to represent each bundle from on-chain available data, using templates pre-approved by The Sandbox. Users will also be able to include custom descriptions for their listings.
• Users will be able to sell their 1x1 or bundled estates via one of three methods:
• Private Sale: The seller will specify a price and generate a private sale link. Only the designated buyer’s wallet will be able to see the sale and complete the transaction.
• Direct Sale: The seller will list their asset for a fixed price on the public marketplace, where any verified user can purchase it.
• GBM Auction: The seller will initiate a GBM Bid-to-Earn auction. Verified users will be able to place bids using SAND, and outbid participants will earn SAND rewards. The assets will be placed in escrow during the auction by the GBM system.
• All three sales methods will be executed atomically, ensuring that the buyer receives the asset and the seller is paid -or the transaction fails. This will eliminate the need for any trusted intermediaries.
• All transactions on the marketplace will be conducted in SAND.
• The Sandbox and The Sandbox DAO will receive a predefined transaction fee from each sale from the seller, automatically distributed to their respective whitelisted wallets. GBM will also get its fee at point of sale. The provisional breakdown is outlined below:
  • GBM - 2%
  • The Sandbox - 2.5%
  • The Sandbox DAO - 2.5%
• The entire marketplace, including the bundling feature, will be fully self-service.

Benefit to The Sandbox Ecosystem

This will provide significant benefit to LAND owners in permitting them to transact more freely with their LAND and with the ability to bundle and sell estates in a trusted and robust manner.

It also provides some income to the DAO via the transaction fees.

Risk	Assessment	Mitigation
Transaction Security	As there will be on-chain transactions being conducted via this marketplace, this carries risk of fraudulent transactions or security breaches.	There will be security checks performed at the point of transaction. Additionally, a security audit of smart contracts will be undertaken to ensure that the correct baseline is set.
Appropriate Bundling	As Estates are a construct within the Sandbox and do not exist on-chain, there is a risk that bundled LAND that are not estates could be sold as estates.	The data for estates will be validated based on public Sandbox data to ensure that all bundles packaged as estates are estates.
Ongoing Management	The service will require ongoing maintenance and sustaining, especially if there are regulatory changes.	GBM will provide support for free for the first 12 months. Following that, support arrangements may need to be determined if the fees generated are not sufficient to sustain.

Budget requested

Overall cost: $60,000

Milestones	How do we measure success?	Expected completion date	Unlock Payment
#1 Project plan	Documented plan and timelines. Wireframes of the solution	Q4 2025	$13,500
#2 Development of Bundle Software	Smart contracts for bundling LAND completed. Frontend and backend development. Accurate image data generation	Q1 2026	$13,500
#3 Integration into GBM x TSB Marketplace	Integrate bundling natively into GBM dApp user flow. Smart contract integration. Allowing for private sales, direct sales and GBM auctions. **Includes:**1 year guaranteed maintenance. Free hosting for 1 year; continued support if fees sustain costs	Q1 2026	$20,000
#4 Estate validation	Tool to ensure that Land is appropriately bundled as Estates.	Q1 2026	$3,000
#5 Security Audit	External audit report covering all required Smart contracts	Q1 2026	$10,000

Team/Author Background

GBM have an established relationship with the Sandbox and has already completed 3 successful auction events, selling hundreds of assets, with each getting bigger then the last and netting more revenues for The Sandbox. Outside of this GBM has completed over 80,000 auctions without any issues and is working with notable web3 projects such as Decentraland, Unstoppable Domains and Aavegotchi just to name a few. The founders are fully doxxed and have been working in the blockchain space since 2018, whilst being involved as early as 2013.

Hugo McDonaugh, CEO - Hugo McDonaugh - GBM | LinkedIn

Edouard Bessire, COO - Edouard Bessire - GBM | LinkedIn

Guillaume Gonnaud, CTO - Guillaume Gonnaud - Cryptograph, MyNFT, gbm.auction | LinkedIn