One margin account,
many venues.
Twenty-four contracts on Arbitrum Sepolia, the core stack mirrored to Robinhood Chain. Stylus for the math, Solidity for the integrations. Click any piece to inspect it, then watch a position flow through the whole system.
Every piece, and what it does.
The router dispatches a signed transaction to the right place: collateral lives in Coffer, margin is priced by Plinth, each venue has its own adapter, and Vigil + Lantern keep the system honest. Hover or tap a node.
A hedged position, step by step.
Press play. Follow a deposit become collateral, two offsetting positions net their risk, and the margin requirement fall live. That is the entire reason Atrium exists, animated through the real contract path.
Press Play the flow to trace a position from wallet to venue and back, with the margin saving computed live by Plinth's SPAN engine.
Real addresses, verified on-chain.
Every contract below is deployed on-chain with real bytecode. Solidity source is verified on Arbiscan or Sourcify, Stylus via cargo stylus verify; the core stack was redeployed on 2026-06-07 (testnet cutover) and its source is verified. Which venues are live today versus scaffolded is set out on /docs/honesty. Click any address to copy it.
Solidity verified on Arbiscan or Sourcify · Stylus via cargo stylus verify. Click any address to copy it.
Tokenized equities, finally usable as collateral.
Robinhood Chain is built for tokenized equities. But an equity you can only hold is half an asset; the other half is putting it to work as margin without selling it. That is exactly what Atrium does: it sees your whole book and returns one portfolio margin number, so a position can back trades everywhere instead of sitting idle on one venue. The full Atrium core, Coffer, Plinth, Sigil, Vigil and the Router, is already deployed and running on Robinhood Chain testnet (chainId 46630), the same Rust + Solidity stack verified on Arbitrum. Not a pitch; an on-chain stack you can read.
Without Atrium
A tokenized equity is held on one chain and margined in isolation, idle as collateral. To trade against it anywhere else you post fresh capital, and an agent given access holds the whole wallet.
With Atrium
The same position joins one cross-margin account: one deposit, one buying-power number, freed capital across every venue, and a contract-enforced kill switch on any agent, which can act only inside a signed risk box.
Built to fail loudly, not silently.
Six defensive choices, each addressing a known DeFi blowup vector.
Timelock + multisig
In the mainnet design, every parameter setter is timelock-gated (48h) and emergency pause is multisig-only with no delay (it can pause but cannot upgrade). On testnet today, admin is a single deployer key; the 3-of-5 multisig + timelock is the mainnet target.
Dual-oracle reads
Every Plinth price takes the median of Chainlink and Pyth, with 50 bps tolerance and a 60-second freshness window. Stale or off → revert.
Reentrancy guards
Every state-changing Stylus function carries an is_updating flag, entered before any external call.
Per-block notional cap
Coffer caps how much a single adapter can pull per block. A compromised adapter drains at most ~1% of TVL per block.
AA emergency lever
The Postern Kill Switch routes through Sigil.revoke_all_on_behalf_of, so the revoke counts against the user, not the kill-switch.
No silent fallbacks
Coffer and Plinth revert loudly when USDC state is unreadable, rather than assuming a safe default.
See it running.
The whole stack is live on testnet right now. Faucet test funds, post collateral, and watch your buying-power number move.