> ## Documentation Index > Fetch the complete documentation index at: https://docs.testnet.dev.adipredictstreet.com/llms.txt > Use this file to discover all available pages before exploring further. # Get backend co-signature for vault.mergePositions > Inverse of split. Returns the backend co-signature needed to call `vault.mergePositions(...)` on-chain — burns equal units of every outcome ERC-1155 inside the vault and credits the corresponding USDC amount. The flow: (1) POST this endpoint with `{marketId, amount}` → server signs the MergePositions typed-data and returns the cosig + salt + deadline. (2) Sign the same struct yourself with your EOA against the vault's EIP-712 domain. (3) Submit `vault.mergePositions(kind, collateralToken, conditionId, partition, amount, salt, deadline, ownerSig, backendSig)` on-chain. After it confirms, the platform debits ERC-1155 holdings and credits USDC `available` for the vault. Use cases: closing a hedged position before resolution, freeing locked outcome tokens back into spendable USDC, exiting a market early. ## OpenAPI ````yaml /api-reference/openapi.json post /api/vault/merge-signature openapi: 3.1.0 info: title: PredictStreet core-api description: >- Client-facing HTTP gateway for the PredictStreet prediction-market platform. This spec is hand-written against the NestJS controllers and DTOs in core-api/src/modules/. For the source-of-truth live spec, run `./scripts/pull-openapi.sh` against a running core-api (NestJS exposes it at /api/docs-json). **Partner kinds.** Every authenticated endpoint resolves a request's *effective wallet* from the partner row. `single_wallet` partners bind to one `associatedWallet` set at creation. `multi_wallet` partners declare the actor on every request via an `X-User-Wallet: 0x<40-hex>` header. See the [Partner kinds](/auth/api-keys#partner-kinds) doc for the full contract. version: '2026-06-16' contact: name: PredictStreet partners email: partners@predictstreet.com servers: - url: https://core.api.dev.predictstreet.sde.adifoundation.ai description: Testnet (partner integrator API — final domain TBD) security: [] tags: - name: Deposits description: >- Gasless USDC deposit relay - submit a signed EIP-2612 permit and the platform broadcasts the on-chain deposit for you (no gas). - name: Events description: >- Polymarket-style event grouping with football metadata (group, stage, teams, tags). - name: Tags description: Curated tag taxonomy used to filter events. - name: Markets description: 'Public market data: list, detail, orderbook, trades, OHLC.' - name: Orders description: >- Signed-order place / cancel / read. Requires `X-Api-Key` with `orders:read` / `orders:write` scope; every write additionally requires an EIP-712 signature over the order. - name: Portfolio description: >- Balances, positions, trades, fees, vault info for the key's `associatedWallet`. Requires `X-Api-Key` with `portfolio:read` scope. - name: Matches description: >- admin.matches aggregate — groups several events into one fixture/card (1X2 + first-scorer + over-under under one matchup). - name: Vault description: >- Backend co-signatures for ERC-1155 split / merge, and recovery for off-chain locks when the corresponding chain tx never confirmed. Requires `X-Api-Key` with `vault:write` scope plus an EIP-712 signature over the operation. - name: Leaderboard description: Public ranked leaderboard across PnL / volume buckets. - name: Search description: Global search across users, events, and matches. - name: Withdrawal Security description: >- Self-service withdrawal 2FA (TOTP) and withdrawal-address whitelist. Same endpoints serve the frontend (Privy JWT) and API-key integrators. Mutations need `vault:write`, reads `portfolio:read`. Both are opt-in per wallet and only gate withdrawals once the platform enables withdrawal-security enforcement. paths: /api/vault/merge-signature: post: tags: - Vault summary: Get backend co-signature for vault.mergePositions description: >- Inverse of split. Returns the backend co-signature needed to call `vault.mergePositions(...)` on-chain — burns equal units of every outcome ERC-1155 inside the vault and credits the corresponding USDC amount. The flow: (1) POST this endpoint with `{marketId, amount}` → server signs the MergePositions typed-data and returns the cosig + salt + deadline. (2) Sign the same struct yourself with your EOA against the vault's EIP-712 domain. (3) Submit `vault.mergePositions(kind, collateralToken, conditionId, partition, amount, salt, deadline, ownerSig, backendSig)` on-chain. After it confirms, the platform debits ERC-1155 holdings and credits USDC `available` for the vault. Use cases: closing a hedged position before resolution, freeing locked outcome tokens back into spendable USDC, exiting a market early. operationId: VaultController_requestMergeSignature parameters: - $ref: '#/components/parameters/UserWalletHeader' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MergeSignatureRequest' responses: '200': description: Backend co-signature ready content: application/json: schema: $ref: '#/components/schemas/MergeSignatureResponse' '400': description: Validation error or unsupported market (binary only in MVP) '401': description: Missing or invalid X-Api-Key '404': description: Market not found '409': description: Market not in tradable status '429': description: Rate-limited. See per-endpoint limits in the auth overview. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' security: - ApiKeyAuth: - vault:write components: parameters: UserWalletHeader: name: X-User-Wallet in: header required: false description: >- **Required for `multi_wallet` partners on every authenticated request; ignored for `single_wallet`.** Declares the acting end-user wallet for this request — drives KYC checks, balances/positions/orders attribution, rate-limit buckets, and audit. Lower-cased server-side. Missing on a multi_wallet key → 401 `api_key_user_wallet_required`; malformed → 401 `api_key_user_wallet_invalid`. The on-chain `CTFExchange`/`Vault` contracts still verify EIP-712 signer ↔ vault binding, so loosening API-layer attribution is safe by construction. schema: $ref: '#/components/schemas/EthereumAddress' example: '0x1234567890abcdef1234567890abcdef12345678' schemas: MergeSignatureRequest: type: object required: - marketId - amount properties: marketId: type: string example: NC26-BIN-83479265 amount: $ref: '#/components/schemas/DecimalString' example: '30' description: >- Decimal USDC amount the merge unwraps. Burns equal units of YES + NO inside the vault and credits this much USDC. MergeSignatureResponse: type: object required: - pendingMergeId - kind - collateralToken - conditionId - partition - backendSig - salt - deadline - vaultAddress properties: pendingMergeId: type: string description: >- Stable audit id derived from (wallet, marketId, amountWei, salt). Idempotent for retries. kind: type: integer description: 0 = binary, 1 = neg-risk. collateralToken: $ref: '#/components/schemas/EthereumAddress' conditionId: type: string pattern: ^0x[0-9a-fA-F]{64}$ partition: type: array items: type: string example: - '1' - '2' amount: type: string description: USDC wei (6-decimal). salt: type: string deadline: type: integer vaultAddress: $ref: '#/components/schemas/EthereumAddress' description: >- EIP-712 verifyingContract for the MergePositions struct (the vault, not the factory). backendSig: $ref: '#/components/schemas/HexSignature' description: >- Backend co-signature; pair with the owner's EIP-712 signature in vault.mergePositions(...). ErrorEnvelope: type: object required: - error properties: status: type: integer example: 400 error: type: object required: - code - message properties: code: type: string example: bad_request message: type: string details: type: object additionalProperties: true trace_id: type: string EthereumAddress: type: string pattern: ^0x[a-fA-F0-9]{40}$ example: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb3' DecimalString: type: string description: >- Decimal number encoded as a string to preserve precision (e.g. `'100.5'`). HexSignature: type: string pattern: ^0x[a-fA-F0-9]+$ description: 0x-prefixed hex-encoded ECDSA signature (usually 65 bytes). securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-Api-Key description: >- Partner / integrator key — format `ps_live__`. Issued by PredictStreet ops via the admin panel; never self-service. Never ship to a browser. `multi_wallet` partners must additionally send `X-User-Wallet: 0x<40-hex>` on every authenticated request to declare the acting wallet. See the [API keys guide](/auth/api-keys) for scope taxonomy, partner kinds, rate limits, and rotation procedure. ````