> ## Documentation Index > Fetch the complete documentation index at: https://sdk.avantisfi.com/llms.txt > Use this file to discover all available pages before exploring further. # Build a vault withdrawal transaction (exact USDC out) > Returns an unsigned transaction that withdraws an exact USDC amount from the vault by burning the corresponding avUSDC shares. Withdrawals are immediate but revert if they would push vault utilization above the protocol threshold — check limits via GET /v2/lp/state. ## OpenAPI ````yaml https://tx-builder-testnet.avantisfi.com/openapi.json post /v2/lp/withdraw openapi: 3.0.3 info: title: Avantis v2 API version: 2.0.0 description: >- Calldata builders, EIP-712 intent builders, signed-tx relay, and on-chain reads for the Avantis v2 perp protocol. **Conventions** - Every build/read endpoint accepts both GET (query string) and POST (JSON body) with the same fields; POST /v2/relay is POST-only. - All amounts are human units: `collateralUsdc: 100` = 100 USDC, `leverage: 10` = 10x, prices are plain USD decimals. The API does all on-chain scaling. - Responses use the `{ ok: true, data }` / `{ ok: false, error: { code, message, details } }` envelope. - Calldata responses (`to`, `from`, `data`, `value`) are unsigned — the caller signs and broadcasts (or submits via POST /v2/relay). `from` is who must sign; `value` is hex wei. - Intent responses (`domain`, `types`, `primaryType`, `message`) feed directly into EIP-712 signTypedData; the Avantis operator executes them gas-free for the signer. - Trading endpoints are rate-limited per IP. Start with GET /v2/meta (addresses, enums, units, defaults) and GET /v2/pairs (market catalog). servers: - url: https://tx-builder-testnet.avantisfi.com security: [] tags: - name: meta description: Service metadata, pair catalog, health and metrics. - name: trading description: >- Build unsigned transactions for market/limit opens and closes, margin changes, and position increases (the direct, self-broadcast route). - name: delegate description: >- Authorize or revoke a delegate key that can trade on behalf of a trader (never move funds). - name: token description: >- USDC approval transactions — the one-time prerequisite before trading or LP deposits. - name: intents description: >- Build EIP-712 typed-data payloads to sign; the Avantis operator submits them on-chain so the signer pays no gas (the relayer route). - name: relay description: >- Submit an already-signed transaction through Avantis-operated RPCs: whitelist check, simulation with decoded revert reasons, then broadcast. - name: twap description: >- Time-weighted orders, filled in slices by the operator over a chosen duration. - name: referral description: >- Referral code registration, assignment, ownership transfer, and rebate claims. - name: lp description: >- Liquidity-provider flows on the Avantis USDC vault (ERC-4626 avUSDC tranche). - name: misc description: Keeper reward claims, vault buffer top-ups, and builder-code registration. - name: reads description: >- On-chain lookups the SDK needs for signing correctness: nonces, positions, delegation state, allowances. paths: /v2/lp/withdraw: post: tags: - lp summary: Build a vault withdrawal transaction (exact USDC out) description: >- Returns an unsigned transaction that withdraws an exact USDC amount from the vault by burning the corresponding avUSDC shares. Withdrawals are immediate but revert if they would push vault utilization above the protocol threshold — check limits via GET /v2/lp/state. operationId: postV2LpWithdraw requestBody: required: true content: application/json: schema: type: object properties: caller: type: string description: The account sending this transaction (must sign it). amountUsdc: anyOf: - type: string - type: number description: Exact USDC to withdraw. receiver: type: string description: >- Recipient of the resulting shares/assets; defaults to the caller. owner: type: string description: >- Owner of the shares being spent; defaults to the caller (requires share approval if different). required: - caller - amountUsdc additionalProperties: false responses: '200': description: >- Success envelope: `ok` is `true` and `data` carries the payload documented below. content: application/json: schema: type: object required: - ok - data properties: ok: type: boolean enum: - true description: Always `true` on success. data: type: object description: >- An unsigned EVM transaction. Sign it with the `from` key and broadcast it yourself, or submit the signed bytes via POST /v2/relay. properties: to: type: string description: >- Contract to call (already resolved, e.g. the TradingRouter proxy). example: '0x0000000000000000000000000000000000000000' from: type: string description: >- The account that must sign and send this transaction — the trader, or the delegate when the call is wrapped in `delegatedAction`. example: '0x0000000000000000000000000000000000000000' data: type: string description: ABI-encoded calldata, 0x-prefixed hex. value: type: string description: >- Required `msg.value` in wei as 0x-prefixed hex (hex avoids JSON precision loss on big values). Non-zero when an operator execution fee must be attached — forward it verbatim. example: '0x0' chainId: type: integer description: Chain the transaction is valid on (EIP-155). description: type: string description: Human-readable summary of what this transaction does. meta: type: object description: >- Echo of the resolved request (pair resolution, live prices, fees). Informational only — not part of the transaction. properties: amountUsdc: type: string description: Echo of the exact USDC to withdraw. receiver: type: string description: Recipient of the USDC. example: '0x0000000000000000000000000000000000000000' owner: type: string description: Owner of the shares being burned. example: '0x0000000000000000000000000000000000000000' required: - to - from - data - value - chainId - description '400': description: >- Invalid input (failed schema validation or pre-trade checks like liquidity, leverage bounds, min position size, or market hours). content: application/json: schema: type: object required: - ok - error properties: ok: type: boolean enum: - false description: Always `false` on errors. error: type: object required: - code - message description: Machine-readable error. properties: code: type: string enum: - BAD_REQUEST description: Stable error code for programmatic handling. message: type: string description: Human-readable explanation of what went wrong. details: description: >- Optional structured context — e.g. Zod validation issues on BAD_REQUEST, or `{ target, revertData, decodedError }` on SIMULATION_FAILED. ````