Blend developer docs

Every mint and redemption charges each active constituent separately. The vault adds a basket-owner fee and a separately calculated fixed Blend protocol fee. Routed trades also pay each constituent pool's fee and price impact. The Blend hook pool itself uses fee 0 and therefore adds no separate basket-level trading fee.

Fee calculation

Each basket sets its mint and redeem owner fees separately, up to 100 bps (1%). Read mintFeeBps() and redeemFeeBps() instead of assuming the maximum. Mint calculations round up; redemption calculations round down. Use previewMint and BlendLens.previewRedeem for the exact token amounts.

Onchain fee buckets

treasury[token]

The basket owner can withdraw this bucket. Before withdrawal, anyone may call accrete to move it into holder backing.

protocolFees[token]

Anyone may sweep the complete bucket to protocolFeeRecipient(). Accretion never spends this bucket. If the vault excludes the constituent before a sweep, the unswept balance moves to forfeited with the leg's backing and owner treasury.

forfeited[token]

Recovery value reserved for holders: skipped legs, excluded legs (including any unswept fee buckets on them), and the recovery share new mints pay in. Accretion consumes it before owner treasury.

Route execution

Routed trades pay each constituent pool's fee and price impact. Those costs follow pool accounting and are not split by the vault.

A mint may also contribute to existing forfeited + writtenDown recovery value. This prevents new entrants from claiming value reserved for earlier holders; it is not a fee. The keeper attempts accretion every ten minutes. The vault limits growth to 0.50% per fully refilled 9.125-day step and 20% per year, with at least one share of supply. A leg skipped by redeemExcluding charges no fee and moves its full gross amount from backing to forfeited value.

Execution limits

BlendLens.previewBuy returns cost per share and conservative route capacity. Current throttle headroom is excluded and must be read or indexed separately.

Network

Robinhood Chain mainnet

Chain ID

4663

Native asset

ETH

Public RPC

https://rpc.mainnet.chain.robinhood.com

Explorer

robinhoodchain.blockscout.com ↗

Factory start block

55,989,258

Basket share decimals

18

Canonical quotes

USDG (6 decimals) and native ETH (18 decimals)

GET /abis
GET /abis/basket-factory.json
GET /abis/basket-vault.json
GET /abis/blend-hook.json
GET /abis/blend-router.json
GET /abis/blend-lens.json

Shared infrastructure

Uniswap v4 PoolManager

0x8366a39CC670B4001A1121B8F6A443A643e40951↗

USDG

0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168↗

Native ETH currency

0x0000...0000

Multicall3

0xcA11bde05977b3631167028862bE2a173976CA11↗

Loading ABIs

const manifest = await fetch("/abis").then((r) => r.json());
const vaultAbi = await fetch("/abis/basket-vault.json").then((r) => r.json());

Indexed API

These endpoints are backed by the indexer and are useful for product surfaces. Responses include x-indexed-block. Use contract reads and logs when you need the exact chain head or a trust-minimized source.

GET /api/blend/baskets
GET /api/blend/basket/:address
GET /api/blend/assets
GET /api/blend/holdings/:address
GET /api/blend/activity/:address
GET /api/blend/units
GET /api/blend/leaderboard
GET /api/blend/eth

Every basket row (in baskets, basket and holdings) carries deployedAt, the unix time of its BasketDeployed event, and deployedBlock, both as decimal strings. Each of its legs carries the vault's buckets for that token as raw decimal strings: treasury, protocolFees, forfeited and writtenDown.

activity/:address is the basket's event history, newest first: its latest 150 events of every kind except Accreted, merged with its latest 50 Accreted events. units is the units-per-share history of every vault whose units have changed, in 4-hour UTC buckets: { block, bucketSeconds, vaults }, where each vault has exact and, per token, a start level and steps, pairs of bucket end and units after it, oldest first. exact is false when the replayed history does not end on the units the vault holds now.

Events provide historical state transitions. Live prices, pool depth, reconciliation status, and refilled throttle headroom require current contract reads.

New baskets start operator-locked. A creator may also choose immutable parameters at deployment, permanently disabling later parameter changes.

• Asset exposure. Tokenized stocks provide price exposure, not direct stock ownership, voting rights, or guaranteed dividends. Access may be restricted by location.
• Issuer control. Asset issuers may upgrade contracts, pause transfers, freeze accounts, rebase balances, or stop supporting an asset.
• Liquidity. A single shallow or empty constituent route can stop the routed basket trade even while direct redemption remains available.
• Token behavior. Fee-on-transfer tokens are rejected on mint; unusual transfer behavior can still close issuance or require exclusion.
• Execution. Quotes are estimates. Always set deadlines and minimum-output or maximum-input bounds.
• Operational dependencies. Interfaces, indexers, RPCs, wallets, and automation can be delayed or unavailable. Verify critical state onchain.

Reinvested dividends

Robinhood stock tokens implement ERC-8056. Robinhood reinvests dividends by raising a token's uiMultiplier(), the number of underlying shares one token represents, and leaves raw balances unchanged. BasketVault accounts in raw token units, so a basket keeps holding the same number of tokens while each token represents more shares. Route pools price the token, not the share, so the live NAV reflects reinvested dividends once pool prices adjust to the new multiplier. The app's NAV chart multiplies each per-share stock close by the token's multiplier in force at that close, read from its UIMultiplierUpdated events, so each dividend counts from its effectiveAt. Amounts and timing are set by the issuer and aren't guaranteed; see Risks. Read current values with each token's uiMultiplier() or BlendLens.uiMultipliers(vault).

Fee accretion

Every mint and redemption charges the basket owner's fee, booked to treasury[token], and Blend's protocol fee, booked to protocolFees[token]. Anyone may call accrete(token, unitsDelta) to move value into holder backing, raising units[token] for every share. It spends forfeited first, then treasury, and never protocolFees. Growth is capped at 0.50% of the leg's anchor units (or its current units, if lower) per 9.125-day refill, at most 20% of the anchor a year without compounding, and needs at least one whole share outstanding. The owner can withdraw treasury before it is accreted. forfeited holds value left by redemptions that skipped a leg, legs written off by exclusion, new minters' buy-ins, and recovered write-downs. The app's NAV chart replays each leg's units from the indexer's Accreted and UnitsWrittenDown history, so fee growth counts from the first close after it; when that history can't be read, the note under the chart says fee growth is missing.

NAV chart

Each point is a market close (a 4-hour bar on the 7D range), except that the latest can be a bar still trading. When a range starts before the basket was deployed, the line has one more point: the basket's value at the moment of deployment, each constituent at the close of its last full hourly bar before then (a stock outside trading hours at its last extended-hours price), with its units and multiplier at that moment. The headline change counts from that point, the same on every range, and the line before it is drawn dashed as a backtest: of the starting holdings, or of today's holdings when the units history can't be read. If a constituent's price at deployment can't be read yet, no change is shown until it can. A portfolio's chart counts from the latest launch among the baskets held. Neither returns nor future dividends are guaranteed.

Redemption

redeem and redeemExcluding have no pause check. A pause stops minting and flashRedeem, never ordinary redemption. The redemption throttle cannot be set below 10% of supply per hour (MIN_REDEMPTION_PCT_RATE), and its absolute rate must cover at least a tenth of supply (MIN_REDEMPTION_AMT_DIVISOR). Both are checked whenever throttles are set, and the absolute rate again on every mint, so the whole supply can redeem within ten hourly periods.

Frozen constituents

If a constituent reverts on transfer, a plain redeem reverts with it. Holders can call redeemExcluding(shares, to, skip), or BlendRouter.sell with a skip list, to take every other leg and forfeit the skipped leg's gross amount to forfeited. Only accrete (or unexclude, once the leg is excluded) pays that out to holders, and only while shares are outstanding; if every share is redeemed, resync or unexclude moves what is left to Blend's protocol-fee bucket. While the token stays frozen, that value cannot leave the vault. The operator can exclude a failed constituent at once with setExcluded, or anyone can with forceExclude after two failed transfer probes at least a day apart. unexclude restores it once it transfers again.