X1City is a unified, persistent open world built on the X1 Blockchain and rendered in Unreal Engine 5. It is being designed and built by a single founder — X1 Brains — on top of a working DeFi stack that already ships on X1 mainnet today. The goal is not to be a federation of separate projects. It is to be one coherent city, with one architectural vision, opened up afterward to other projects via property NFTs they can rent or buy.
The build sequence is deliberate: architecture first, properties next, then the agent layer. Buildings, streets, lighting, and terminals are being placed before any property NFTs go on sale. The financial backbone — Lab Work (LB Mint), the LB NFT Marketplace, LP Pairing, Brains Farm, the Incinerator, the Rewards Hub, Cyberdyne Unlimited, and the portfolio tracker — is already live at x1brains.io.
This document is v0.3, a status update covering two new layers built between v0.2 and now. The first is the Genesis Elite Citizen NFT collection — the on-chain founding-member program that establishes citizenship as a transferable Metaplex Master Edition credential. The Phase A internal test deploy is wired end-to-end and currently being stress-tested on a sandbox program ID. The Phase B production launch — the canonical 444 Genesis Elites on a fresh program ID — is scheduled to follow once Phase A validation completes.
The second is X1B, the network agent of the X1.City PROTOCOL. X1B reads live X1 chain state, prices and quotes against xDEX, and signs transactions through a per-citizen paired hot wallet with structural anti-fabrication defenses. The chat surface is hardened, the tool catalog is real (50+ on-chain reads, 4 signed writes), and Genesis holders will receive free unlock as a council-granted perk at mint.
Only 444 Genesis Elites will ever exist. Once Phase B sells out, the founding-member door closes permanently — there is no extension, no second tranche, no surprise drop.
Citizenship layer designed and built — see Section 08 for the full architecture (handle, stamps, AI unlock, transferable credentials).
X1B agent layer designed and built — see Section 10 for the tool surface and defense-in-depth model.
Roadmap restructured — Phase A (citizenship + agent) inserted as a sequencing milestone before Phase B (property layer). See Section 11.
The city itself is the asset. Every parcel is land. Every building is a property. Every protocol that moves in is a tenant. As the city grows, the value of what's already inside it grows with it. DeFi runs underneath. The X1B agent layer is already operational. The architecture is the foundation of all of it.
The idea for X1City was sparked in a Telegram conversation between a few X1 builders earlier in 2026. The shared image was a Monopoly board. The question was: what if the blockchain itself was the city — and what if instead of competing for the same users, builders could each contribute something to a single, unified open world?
The conversation seeded the concept. The build, however, is solo. Two of the original co-conceivers stepped away from X1 development as the regulatory landscape shifted in early 2026. X1 Brains carries the work forward: designing the city, modeling it in Unreal Engine 5, and shipping the DeFi stack underneath at x1brains.io. The Telegram conversation gets credit for the spark. The execution is one builder's work.
The domain x1.city was secured. The first buildings were placed in Unreal Engine 5. The architecture pass — exteriors, streets, lighting, terminals — is the current focus. Interiors, properties, and on-chain interactables are next.
"Build the city tight. Place the buildings. Light it up. Then open the gates and let other projects move in. The economy of X1City is the city itself."
— X1 Brains · Build NotesThe deliberate choice from day one: keep it underground while the architecture comes together. Don't announce a concept — have something real before opening the gates. v0.3 of this whitepaper marks the point where the citizenship layer is live: real NFTs on mainnet, the X1B AI agent terminal running, and the property economy approaching design lock.
X1City is being built with one design principle running through everything: architecture first. Buildings, streets, lighting, and the visible structure of the city come before properties go on sale and before agents come online. The goal is to build something real and let the economy assemble around it — not the reverse.
"One builder. One city. Build it tight. Ship what's real. Open the gates when the architecture is done."
— X1 Brains · Build NotesMost blockchain metaverses sell parcels before there's a world to put them in. X1City inverts that: the city is being designed, modeled, and lit first. Once the architecture pass is complete, properties and parcels become NFTs that other projects can rent or buy to host their dApps inside the world. The order matters — and the order is honest.
X1City does not sell what doesn't exist yet. The land NFTs, the property deeds, and the NPC agent layer are all real future steps — but each ships when the underlying work is in place. The DeFi stack is on mainnet. The Genesis citizenship NFT layer is on mainnet (Phase A). The X1B agent terminal is live. Properties open after the architecture pass. The gates open when the city is real enough to walk through.
Most blockchain worlds launch a marketplace before there's anything to put in it. They sell parcels backed by promises of what the world will eventually look like, and the gap between the rendering and the reality kills momentum. X1City is being built in the opposite order.
| Phase | What Ships | Why |
|---|---|---|
| Phase 0 — Already Live | x1brains.io: portfolio tracker, LB Mint, LB NFT Marketplace, Incinerator, Rewards Hub, Cyberdyne, LP Pairing, Brains Farm | Working DeFi stack on X1 mainnet. Anchors every claim in the whitepaper. |
| Phase A — Citizenship + Agent (LIVE) | Genesis Elite Citizen NFT collection (56-edition test mint), X1B AI agent terminal, citizen credentials, on-chain handle + stamps system. | Prove the citizenship-and-agent layer end-to-end before scaling to the full 444 edition production drop. |
| Phase 1 — Architecture | UE5 city: building exteriors, streets, lighting, terminals, signage. Concept-to-blockout pass complete; visual polish ongoing. | The city has to exist before parcels can be sold honestly. |
| Phase B — Property NFTs | Full 444-edition Genesis collection on production program ID. Land parcels and building deeds as NFTs. Tenant onboarding. | Once the city is real, the economic primitive becomes the city itself. |
| Phase 3 — NPC Agents | X1B-class agents bound to specific buildings and districts. NPC characters aware of live on-chain state, voiced by the same model that powers the terminal. | NPCs move into a city that already works. |
The architecture-first approach has three properties that matter. First, every claim in this whitepaper is backed by something concrete — either already shipping (the DeFi stack, Phase A citizenship, the X1B terminal) or visibly under construction (the city itself). Second, when properties go on sale, buyers can walk through what they're buying instead of trusting a roadmap. Third, the order matches how real cities form: skylines come before zoning maps come before tenants come before commerce.
If a feature is on the roadmap, the underlying work has to be visible before the feature is sold. Phase A citizenship shipped before Phase B because the program logic and the AI terminal needed real exercise. Parcels open after the architecture pass. The whitepaper shows the order — the build follows it.
Phase 1 of X1City is a single unified open world built in Unreal Engine 5, currently in its architecture pass — exteriors placed, streets and lighting set, no interiors yet. Rather than a federation of separate districts, the city is being designed as one cohesive environment. Different zones have different purposes, but they're all part of the same world and built by the same hand.
As the city expands, additional zones can be opened — themed districts for gaming, marketplaces, or specific tenant communities. Brains will design and build the architecture; tenant projects will occupy and operate the protocols inside. The city itself remains a unified work, designed and maintained by one builder.
X1City sits on top of a working DeFi stack already deployed on X1 mainnet. These are not roadmap items — they ship today at x1brains.io and they are the financial backbone the city is being built around.
Lab Work is a deflationary minting protocol on X1. Users burn BRAINS tokens and pay an XNT fee to mint LB — a Token-2022 asset capped at 100,000 units. The pricing tiers up as supply increases. The Xenblocks Amplifier lets holders of XNM, XUNI, and XBLK earn bonus LB on each mint. 100% of BRAINS used in mints is permanently burned. LB itself carries a small Token-2022 transfer fee that flows to the treasury. Every parameter — tier prices, supply cap, transfer fees — is enforced by the on-chain program.
The Brains LP Pairing Marketplace solves a problem every token launch faces: to create a trading pool, you need two assets, but most builders only have one. The protocol enables trustless peer-to-peer liquidity pool creation directly on XDEX. A lister posts what they want to pair and at what value. A matcher brings the complementary asset. The pool spawns automatically with neither side having to trust the other.
The Brains Farm pairs with the LP Pairing Marketplace. Stake LP tokens (BRAINS/XNT or LB/XNT) and earn rewards across three lock tiers — 30 days at 2× weight, 90 days at 4×, 365 days at 8×. A 3-day grace period protects against accidental commits. Past grace, an early-exit penalty applies, with discounts for LB holders. Rewards are issued via a continuous accumulator, claimable every 24 hours after the grace period. Forfeited rewards from early exits stay in the vault and boost APR for committed stakers.
The x1brains.io hub itself includes the portfolio tracker (XNT, SPL tokens, Token-2022 assets, XenBlocks holdings), the LB NFT Marketplace with list/buy/cancel/boost functions, the Incinerator (burn BRAINS → earn LB Points → ascend the leaderboard), the Rewards Hub with weekly prize vaults, and Cyberdyne Unlimited — the X1 citizen registry with tier rankings and the live leaderboard.
Every building in the Financial Quarter has a real on-chain analog. When you walk into the Lab Work building in UE5, you are looking at the same protocol that's already minting LB on mainnet. The architecture is just the visual surface — the engine is already turning underneath.
Once the architecture pass is complete, X1City opens its property layer. Land parcels and building deeds become NFTs. Citizens can own pieces of the city. Tenant projects can rent or buy buildings to operate from inside the world. This is the primary economic primitive of X1City — not a token economy bolted onto a 3D environment, but the city itself functioning as the asset.
| For Citizens | For Tenant Projects |
|---|---|
| Own a city plot — Land NFT | Rent a building — run dApps inside |
| Hold a building deed — Property NFT | Buy a parcel — permanent address in the city |
| Stake LP tokens in Brains Farm — earn rewards | Operate a storefront with in-world foot traffic |
| Lease or sell on the open market | Apply for branded zones (by arrangement) |
| Footprint scales with holdings | Direct exposure to X1City citizens |
The economic logic is straightforward: as more tenant projects move in, the city becomes more useful. As the city becomes more useful, it draws more citizens. As more citizens arrive, the value of every property inside it appreciates — for both early citizens and early tenants. The city itself is the network effect. The longer it runs, the denser the value gets.
Tenant projects looking to occupy a building or branded zone in X1City will go through a structured onboarding once the property layer goes live. The goal is to keep the city coherent — not every zone is open to every project, and the architectural integrity of the city is treated as a long-term asset. Details on the tenant program will be published as Phase B approaches.
Genesis Elite Citizens are the founding 444 of X1.City — and that number is permanent. Once the 444th is minted, the door closes. There is no extension, no Phase 2 of the Genesis collection, no surprise drop. The founding-member tier is exactly 444 and never larger. Each one is a real Metaplex Master Edition NFT (max supply locked at 1, no prints, no copies) minted on the X1 Blockchain. Holding one is your permanent on-chain identity in the city — a credential that travels with the NFT, not with your wallet, so it can be transferred or sold like any other NFT and the new owner inherits the citizenship.
It's the smallest founding-member tier the city can carry without diluting. Big enough to fill the Council chamber and seed the property economy. Small enough that every Genesis holder is unambiguously early. Once the production drop sells out, the only way to become a Genesis Elite is to buy one from someone who already has one. That's it.
Think of it like an exclusive founding-member card. There are two visual styles, but both grant exactly the same rights and benefits inside X1.City. The difference is purely the artwork on the card.
The Phase A test deploy — 56 editions on a sandbox program ID with a cheap bonding curve (0.001 → 1.785 XNT) — is wired end-to-end and being stress-tested internally so the full flow can be exercised cheaply before the production launch. Phase B is the production drop: a fresh program ID, 444 editions, retuned bonding curve, public mint announcement to follow. The Phase A test mints stay collectible but the canonical "Brains Elites" collection is the Phase B one.
Most NFT projects store your reputation or progression on a separate database keyed to your wallet — when you sell the NFT, the new owner gets a blank slate. X1.City is different. Your citizenship data (handle, stamps, AI agent slots, council-granted perks) is stored in an on-chain record that is keyed to the NFT mint itself, not your wallet. When you transfer the NFT, the new holder inherits the full credential. The handle stays. The stamps stay. The AI Agent Approved status stays.
In technical terms: the CitizenNftData PDA is seeded by the NFT mint address rather than the original minter's wallet. In plain terms: the credential follows the token. It's how a real ID card works — if you hand your ID to someone, they have your ID.
Every Genesis edition is a verified item of the parent "Brains Elites" Collection NFT. This matters because Solana wallets, explorers, and marketplaces (Phantom, Backpack, X1 Explorer, Tensor, Magic Eden once they index X1) look for the Verified Collection badge to know an NFT is part of a real, curated set. Without it, NFTs show up as standalone "Unknown Token" entries with no group identity. With it, your Genesis NFT renders alongside the other 443 (or 55 in test) as part of one canonical collection.
X1.City also has Regular Citizens — anyone can register as one by burning 444 BRAINS tokens through the credentials page. Regular Citizens are wallet-bound (the citizenship is tied to your wallet, not to a transferable NFT) and they don't get the council-granted AI perk. They burn the same 444 BRAINS to unlock AI access that Genesis holders get for free.
A wallet can hold one or the other — never both. If you mint a Genesis NFT, you can't also register as a Regular Citizen with that same wallet, and vice versa. This is the Genesis-Regular exclusion rule, enforced on-chain.
Genesis NFTs are minted with a 0% royalty fee for Phase A and Phase B. Resale on any Solana-compatible NFT marketplace is fully supported. The NFT is a Metaplex Master Edition with max supply locked at 1 (no prints, no copies). It's a true 1-of-1 within the collection.
Many of the long-lived assets inside X1City — citizenship, land, buildings, in-world items — are NFTs with smart metadata that makes them dynamic, composable, and tied to real city activity. The more land you hold, the more buildable footprint you have. Buildings can host protocols. Genesis citizenship NFTs carry transferable credentials. Fungible assets (BRAINS, XNT, LB, LP tokens from xDEX pools) remain as standard SPL / Token-2022 tokens — separate primitive, separate role.
| Asset Type | Mechanics | Status |
|---|---|---|
| Genesis Citizen NFT | Metaplex Master Edition (1/1). 444 cap (56 in Phase A test). Mint-keyed credential carries handle, stamps, AI unlock, agent slots through transfers. See Section 08. | Phase A live · Phase B production-ready |
| Land Parcel NFT | Ownership of city blocks. More land = more buildable space for protocols, games, and storefronts. | Phase B — opens after architecture pass |
| Building Deed NFT | Ownership of specific buildings. Can be leased to tenants, upgraded, or used to host protocols. | Phase B — alongside parcel sale |
| Item NFT | In-world items used in games, tasks, and commerce. Smart metadata enables item evolution. | Long-term |
LP positions from the Brains LP Pairing Protocol are standard fungible SPL tokens, not NFTs — that's why they're stakeable in Brains Farm and tradable on xDEX like any other token. Likewise, BRAINS, XNT, and LB are SPL / Token-2022 fungibles. The NFT primitive is reserved for assets that need uniqueness, transferable identity, or smart-metadata progression — citizenship, land, buildings, items. Each primitive picks the standard that actually fits its role.
A longer-term direction the team has explored is extending the trustless pairing logic from token-token pools into NFT-bound market mechanics for in-world assets — bringing liquid-market infrastructure to items, deeds, and parcels as the marketplace matures. That's vision, not built; the LP Pairing Protocol today does token-token pairs only.
Most blockchain projects talk about AI agents as a future vision. X1.City is past that conversation. X1B is operational — the first AI agent on the X1 Blockchain with end-to-end on-chain awareness, transaction signing, and per-citizen vault isolation. The chat terminal is live on the citizenship test deploy, the model is connected, and the tool surface is real. Phase 2 of the agent layer is NPC characters bound to specific buildings inside the UE5 city — same engine, scoped to the data their building cares about. But the engine is already on.
X1B is the agent of the X1.City PROTOCOL Network. Walk up to the terminal, ask anything about X1, and X1B answers from live mainnet data — not from training cache, not from an outdated index. Every read query hits the chain in real time. Every write transaction is signed by a paired hot wallet that the citizen controls. The defense surface around the agent is hardened: per-citizen vaults with cryptographic isolation between holders, server-enforced spending caps, plan-token-bound write confirmations that the model cannot fabricate around, and a fabricated-signature scrubber that strips made-up base58 from the chat stream. Citizens stay in control: every write action shows a preview, requires explicit confirmation, and is bounded by spending caps the citizen sets themselves.
Every other "AI agent that signs transactions" project has the same nightmare scenario: the model fabricates a transaction signature, claims success, and the citizen believes a tx happened that never did. X1.City's signing path is engineered specifically against that. Write actions follow a three-stage protocol — preview, confirm, execute — where the execute step is a separate server-side call (bypassing the model entirely) and the resulting transaction signature comes from the actual signed-and-confirmed network response, not from anything the model generated. If the model ever tries to invent a signature, the stream scrubber detects the base58 shape, redacts it, and shows a loud 🚫 OVERRIDE banner explaining nothing actually happened on chain. It is not possible for X1B to make up a transaction that didn't happen. That's by construction.
Every Genesis Elite NFT comes with the "AI Agent Approved" stamp auto-issued at mint. Regular citizens have to burn 444 BRAINS or 1.11 LB to unlock X1B. Genesis holders skip the burn entirely. The unlock is the founding-member perk most people will use the most. You still top up message credits like everyone else — but the access door is open from day one.
Once the UE5 architecture pass lands, the same agent infrastructure gets bound to characters living inside the city render. Walk up to the LB Marketplace clerk and they tell you what just listed. The Lab Work technician knows what just minted. The Brains LP Pairing concierge knows what's open and what's matched. NPCs work for the city, not for individual citizens — they're voiced by the same model X1B uses but scoped to whatever building they live in.
The chat terminal is the simplest surface for the agent layer — text in, text out, no 3D rendering required. Shipping X1B first lets the model, tool surface, and signing infrastructure get exercised by real citizens before they get wired up to building characters inside the city. By the time NPCs ship, the underlying engine has already been hardened.
X1City is built in phases that match the architecture-first principle. Each phase opens once the underlying work is in place. No phase ships ahead of its foundation. The current state: Phase 0 (DeFi stack) is live; Phase A (citizenship + agent) is live in test mode; Phase 1 (architecture pass) is in active construction.
| Phase | Scope | Status |
|---|---|---|
| Phase 0 — DeFi Engine | x1brains.io: portfolio tracker, Lab Work / LB Mint, LB NFT Marketplace, Incinerator, Rewards Hub, Cyberdyne Unlimited, LP Pairing Marketplace, Brains Farm | Live on X1 Mainnet |
| Phase A — Citizenship + Agent | Genesis Elite Citizen NFT mint (Metaplex Master Edition, 56-edition test deploy). X1B AI agent terminal. Citizen credentials, handles, stamps, AI access gating. | Live on X1 Mainnet (test program ID) |
| Phase 1 — Architecture | UE5 city — exteriors, streets, lighting, terminals, signage. Concept-to-blockout pass complete; visual polish ongoing. No interiors yet. | In Progress |
| Phase B — Property Layer | Full 444-edition Genesis collection on production program ID. Land parcel and building deed NFTs. Tenant onboarding for other projects. Lease and ownership mechanics. | Design |
| Phase 3 — City Hall | Central hub interior. Live dashboards. Network terminals. Cross-protocol portal. City directory as more tenants move in. | Planned |
| Phase 4 — NPC Agents | Building-bound NPC characters powered by the same agent infrastructure as X1B — guides, operators, shopkeepers — aware of live on-chain state. | Long-Term |
| Phase 5 — Expansion | Additional zones, themed districts, mobile integration, marketplace evolution. Scope determined by what the city actually needs at that point. | Vision |
As of mid-2026, the space is active with AI, blockchain, and metaverse experiments — but no project has shipped the convergence X1City is building toward, particularly with the architecture-first sequencing. Most existing projects hit one or two of the core pillars. X1City's distinguishing feature is that the DeFi engine, the citizenship NFT layer, and the AI agent terminal are all already running before the city even launches its property layer.
| Project | Strength | Gap vs X1City |
|---|---|---|
| Virtuals Protocol | Agent tokenization, on-chain agent identity, monetization | No persistent 3D world, no UE5 architecture, no integrated DeFi stack |
| Decentraland | Virtual land economy, user events, established community | Lightweight AI, no agent companions, weak DeFi integration, ports rather than native chain build |
| The Sandbox | User-created content, large ecosystem, partnerships | No native AI agent layer, centralized elements, no on-chain DeFi engine running underneath |
| ElizaOS / ai16z | Autonomous on-chain agents, wallet capabilities, DeFi execution | No 3D world, no visual environment, no property economy, no citizenship NFT layer |
The pieces — UE5 for visuals, Token-2022 for asset design, Metaplex for transferable credentials, Anchor for smart contracts, large language models for agents — have all matured enough that this is now buildable by a single technically capable founder. X1City is positioning to be the first to ship them in the right order.
X1City is built by a single founder. The idea was sparked in a Telegram conversation with a few X1 builders earlier in 2026, but the design and build are solo work. The other co-conceivers stepped away from X1 development as the regulatory landscape shifted; X1 Brains carries the work forward.
X1 Brains is the creator of x1brains.io, the most complete hub on the X1 Blockchain. Its modules include the portfolio tracker (XNT, SPL, Token-2022, XenBlocks), the LB NFT Marketplace (scan, list, buy, mint LB tokens), the first Proof of Burn token on X1 (Lab Work), the Incinerator burn engine that lets users burn BRAINS to earn LB Points and ascend the leaderboard, the Rewards Hub with weekly prize vaults and Lab Work submissions, Cyberdyne Unlimited — the Imperial Citizen Registry for looking up X1 citizens by username or wallet — and the Brains LP Pairing Marketplace, the first trustless LP pair creation platform on X1. Then the Brains Farm staking program. Now the citizenship and agent layer at x1.city.
Recognized as #3 Top Builder on X1 and Cyberdyne Approved. Now designing and building X1City in Unreal Engine 5, with the x1.city domain secured. The full stack — DeFi programs in Anchor/Rust, Genesis NFT program with Metaplex CPI, X1B agent gateway with per-citizen vault, frontend in React/TypeScript, city in UE5 — is being built and maintained by one shop.
X1City is not finished. The whitepaper you're reading is v0.3 — a snapshot of where the city is right now and where it's heading. It will be revised again as Phase 1 architecture wraps and Phase B properties open. This is a living document because the project is a living build.
The path is honest about itself: the DeFi engine is shipping at x1brains.io; the citizenship NFT layer and the X1B AI agent terminal are live in Phase A test mode at x1.city; the city is in its architecture pass; properties open after the architecture is real. Each step proves the next one is buildable. No promises sold ahead of work done.
If you found this early — you're early. The DeFi stack is live to use today on x1brains.io. The Genesis Elite citizenship program is built and stress-testing on the Phase A sandbox. The X1B agent terminal is operational. The city renders are coming as the architecture pass advances. The property layer opens when the city is real enough to walk through. That's the deal.
The numbers don't change: 444 Genesis Elite Citizens. Ever. 88 Brains-track, 356 Lab Work-track. Once Phase B sells out, the founding-member tier is closed permanently. The people who hold a Phase B edition will have the lowest edition numbers, the cleanest credentials, the first walkable access to the Council district, the first crack at Land NFTs when Phase B properties drop, and the free X1B unlock from day one. That's not a marketing promise — that's the on-chain protocol behaving exactly as it's written.
"Build it tight. Place the buildings. Light it up. Then open the gates and let other projects move in. The economy of X1City is the city itself."
— X1 Brains · Build NotesPhase A validation completes → internal stress test on the citizenship + X1B stack closes out, lessons fold back into the production program.
Phase B production launch → fresh program ID, full 444-edition Genesis collection, retuned bonding curve, public mint announcement.
UE5 architecture pass continues → exteriors, lighting, terminal placement advance toward interior-ready state.
Property layer design lock → Land NFT and Building Deed mechanics finalize ahead of Phase B properties.
Follow the build on Twitter @X1Brains and Telegram. Phase B mint announcement will be posted there first.
x1.city · X1 Blockchain · Unreal Engine 5 · Anchor · Token-2022 · Metaplex · X1B
X1CITY WHITEPAPER v0.3 · LIVING DOCUMENT · MAY 2026 · x1.city · X1 BLOCKCHAIN · UNREAL ENGINE 5
BUILT BY X1 BRAINS · ARCHITECTURE FIRST