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Prime brokerage · Unified margin · Testnet

One wallet. Every venue.
One buying-power number.

Fig. 01 · Capital convergence
Plan view · illustrative schematic
Sheet 02 / 08
Atrium · June 2026
Hyperliquid HIP-3
HL-HIP3
Tokenized-stock perps
$1,247,820
USDC · WETH34.8%
Hyperliquid HIP-4
HL-HIP4
Permissioned perps
$483,160
USDC13.5%
Aave Horizon
AAVE-V3
RWA collateral
$892,440
aUSDC · USTB24.9%
Pendle V2
PENDLE
Fixed-yield · PT
$320,500
PT-stETH8.9%
Pool · Unified margin
Schematic
$10,772,190
Buying power · 3.0× portfolio margin
Collateral $3.59M
Plinth · margin ok
Curve
CURVE
Stableswap LP
$186,720
3pool LP5.2%
Trade.xyz
TRADE
RFQ · dark pool
$401,890
WETH · WBTC11.2%
Polymarket
PMK
Prediction · CTF
$58,200
USDC1.6%
RH-Chain
RH-NTV
Native spot · pending
-
-0.0%
Arbitrum SepoliaChainlink CCIPERC-8004ERC-4337 · 7702
Plinth · margin engine

Plinth computes a SPAN-style cross-product margin number in Rust, deployed as Stylus. The same math costs 10x to 100x more gas in equivalent Solidity, which is why it has not shipped onchain elsewhere.

Capital efficiency, mathematically.

https://useatrium.me/app/portfolio
live
Vault · Coffer · Arbitrum Sepolia
$24.95
● live · read from Scribe
Total collateral
$24.95
Venue adapters
7 / 7
Margin engine
Stylus
Open positions
Venue
Adapter
Status
Collateral
Chain
Hyperliquid HIP-3
HL-HIP3
Deployed
USDC · WETH
Arbitrum Sepolia
Hyperliquid HIP-4
HL-HIP4
Deployed
USDC
Arbitrum Sepolia
Aave Horizon
AAVE-V3
Deployed
aUSDC · USTB
Arbitrum Sepolia
Pendle V2
PENDLE
Deployed
PT-stETH
Arbitrum Sepolia

Live vault TVL · 1 venue live today (Aave, via a test pool); the rest are deployed and register through mainnet · honest disclosures

Aqueduct · Chainlink CCIP

Aqueduct routes assets through Chainlink CCIP. Collateral posted on Robinhood Chain becomes Plinth credit on Arbitrum in under ten seconds.

Move collateral between chains in one transaction.

https://useatrium.me/app/transfer
sample
Cross-chain transfer · Aqueduct
From
Robinhood Chain
50,000 USDC
Balance · 1,284,300
CCIP bridging
To
Arbitrum Sepolia
50,000 USDC
Plinth credit posted
Estimated time · 8.4s
CCIP fee · $0.00 testnet
● Chainlink CCIP testnet

How a cross-chain transfer flows through Chainlink CCIP · walk the flow in /app/transfer (the testnet CCIP lane is pending)

Sigil · ERC-8004 mandates

You sign one Intent Sigil, an EIP-712 mandate authorising one agent, for one strategy, for a finite window. Postern issues a session key. Your master key never moves.

Agents trade with bounded mandates.

https://useatrium.me/app/agents/delphi.eth
sample
Sigil · agent.delphi.eth
Volatility arbitrage · running
● sample
Sigma signs Intent Sigil
intent.sigil · agent=delphi · max=$50k · ttl 7d
now
Postern issues session key
0x9f3a…b71d · cap $50k · 7d
Agent emits Action Sigil
portico.hyperliquid.openLong(WETH, 4×)
Vigil checks mandate · ok
✓ within Plinth headroom · 0.32× util
Session · 0x9f3a…b71dCap $50,000 · used $12,418Revoke ↗

How a bounded agent mandate executes, step by step · issue a live mandate in /app/agents

Lantern · proof-of-reserves

Lantern publishes a signed Merkle attestation about every 45 minutes. Anyone can verify a balance against it locally, without trusting Atrium.

Every dollar, on the public record.

https://useatrium.me/lantern
live
Proof-of-reserves · Atrium
Merkle attestation · every 45 min
Verified · 24 min ago
On-chain reserves
$23.31
Redeemable claims
$23.31
Backing
100%
Merkle root
0xee46…f38e
Block #279,530,987 · Arb-SepoliaOpen the verifier ↗

Live proof-of-reserves · read directly from Lantern on Arbitrum Sepolia · full record at /lantern

$24.95
Live testnet TVL
via Scribe · Arbitrum Sepolia
Registered agents
Rostrum index
Codex queries · 24h
x402 micropayments
7 / 7 · 1 openable
Venue adapters deployed
Aave Horizon openable today; rest register as lanes land
The system

Eighteen subsystems. One building.

The codebase is named after the parts of a Roman house. Plinth carries weight. Postern is the small gate. Aqueduct moves water. Each subsystem owns its room.

Fig. 02 · The Atrium of Atrium
Plan view · domus floor plan · all 18 subsystems
Sheet 03 / 08
Atrium · June 2026
-, PLAN VIEW · upper levels, --, SECTION · foundation, -PERISTYLEATRIUMTABLINUMvia compluvium →PorticoVenue frameworkSigilAgent mandatesRostrumAgent marketplaceCodexx402 paid APIsScribeSubgraph indexerLIVEPOOL · UNIFIED MARGINImpluviumUnified marginArchiveOff-chain risk labTabletTax · UK · US · DEEdictJurisdiction tiersPraetorCLI · opsCofferERC-4626 vaultsLanternProof-of-reservesCohortDesign partnersCuratorAdapter grantsPosternWallet abstractionAqueductChainlink CCIPPlinthMargin engine · StylusVigilLiquidation engine · StylusStoaOptions · Phase 2P2FOUNDATION · STYLUS (RUST → WASM)NSCALE 1:1 · TESTNET0100m1,060600
Hover a room
Eighteen subsystems arranged as a domus. The impluvium at the centre is the unified margin pool. Foundation engines carry the load. Side gates handle traffic in and out.
Subsystems

Each subsystem owns one responsibility. Thirteen are live on testnet today; all eighteen ship at launch, with Stoa conditional on Phase-2 funding.

Eighteen named pieces. Four architectural blocks.

Block 01

Risk engine

Cross-product margin, liquidations, options pricing. Rust, deployed as Stylus.

4 subsystems
01P1
Plinth
Margin engine
Stylus · Rust
02P1
Vigil
Liquidation engine
Stylus · Rust
03P2
Stoa
Options pricing
Stylus · Rust
12P1
Coffer
ERC-4626 vaults
Stylus · OZ
Block 02

Venues + cross-chain

Portico framework, Chainlink CCIP bridge, wallet abstraction layer.

3 subsystems
04P1
Portico
Venue framework
Solidity · OZ
05P1
Aqueduct
Cross-chain bridge
Solidity · CCIP
18P1
Postern
Wallet abstraction
ERC-4337 · 7702
Block 03

Agents + APIs

ERC-8004 mandates, copy-trading marketplace, paid agent surface, indexing.

5 subsystems
06P1
Sigil
Agent credit
Stylus · ERC-8004
07P1
Rostrum
Agent marketplace
Solidity · Indexer
08P1
Codex
Paid agent APIs
Node · x402
09P1
Scribe
Indexer
The Graph
10P1
Archive
Off-chain risk lab
Python
Block 04

Trust + ops

Proof-of-reserves, compliance, tax exports, CLI, partner programmes.

6 subsystems
11P1
Lantern
Proof-of-reserves
Vercel · Merkle
13P1
Edict
Jurisdiction tiers
Solidity · Sumsub
14P1
Tablet
Tax reporting
Node
15P1
Praetor
CLI · ops
Rust · Foundry
16P1
Cohort
Design partners
BD · program
17P1
Curator
Adapter grants
ARB · grants
Architecture

Risk math lives in Rust, deployed as Stylus. The venue layer lives in Solidity, on OpenZeppelin patterns. Chainlink CCIP is the messaging bus between chains.

Stylus for hot math. Solidity for the venue layer.

L01
Postern
User entry · wallet abstraction
Passkey loginGas sponsorshipSession keysSocial recovery
PWA · Next.js
L02
Backend services
Off-chain orchestration
Tablet · taxCodex · x402Aqueduct coordinatorRostrum copy-trade
Single region · EU
L03
Stylus
Rust → WASM · hot math
Plinth · marginVigil · liquidationsStoa · optionsCoffer · ERC-4626Sigil · ERC-8004
Robinhood · Arbitrum Sepolia
L04
Solidity
Venue layer
Portico v1.0.09 adapter contracts
OpenZeppelin
L05
Oracles + data
Free testnet feeds
Price FeedsCCIP testnetPythScribe
Chainlink · Pyth · The Graph
Built with

The venues and infrastructure rails Atrium integrates across Arbitrum Sepolia and Robinhood Chain testnet.

Testnet · now open

Step inside.
The testnet is open.

The faucet drops 5 test USDC and 0.0005 test ETH. Onboard with a passkey, then post collateral and trade across venues with one margin number.

Testnet only · not investment advice
Unified margin · EVM · testnet

One wallet. Every venue.
One buying-power
number.

Atrium is unified margin prime brokerage for the EVM. Post collateral once. Trade across onchain venues against one figure, computed onchain by Plinth.

Arbitrum Sepolia Chainlink CCIP ERC-8004
Fig. 01 · Capital convergence
Plan view · illustrative schematic
Sheet 02 / 08
Atrium Labs · 2026
Pool · unified margin
$10,772,190
Buying power · 3.0× portfolio margin
HL-HIP3
Tokenized perps
$1.25M
AAVE-V3
RWA · USTB
$892K
TRADE
RFQ · dark pool
$401K
PENDLE
PT · stETH
$320K
HL-HIP4
Permissioned
$483K
CURVE
3pool LP
$186K
10×
01 · The product

Capital efficiency, mathematically.

Plinth reads collateral across every venue and returns one cross-product margin number per block.

Plinth · Stylus
SPAN-style portfolio margin, onchain.
The hot risk loop lives in Rust via Stylus, while the venue layer stays Solidity and standards-friendly.
Buying powerlive
$24.95
Venue adapters7 / 7
MarginSPAN
EngineStylus
02 · Cross-chain

Move collateral in one transaction.

Aqueduct routes through Chainlink CCIP so collateral posted on one chain becomes Plinth credit on another.

From
arb-sepolia
To
rh-chain
50,000USDC
CCIP fee · testnet · estimated 8.4s
03 · Agents

Agents trade with bounded mandates.

Sigil turns one typed signature into a finite mandate: one agent, one strategy, one cap, one expiry.

Intent Sigil signedagent · cap · ttl
Session key issuedPostern · scoped key
Action Sigil checkedVigil · mandate ok
Live testnet surface
TVL
$24.95
from Scribe
Venues
7/7
registered
Lantern
0xee46…f38e
24 min ago
Agents
Rostrum

Step inside. The testnet is open.

Onboard with a passkey, claim faucet funds, then post collateral against one margin number.