> ## Documentation Index > Fetch the complete documentation index at: https://docs.soroswap.finance/llms.txt > Use this file to discover all available pages before exploring further. # Build > Builds an **unsigned XDR** for a quote. If **Gasless Trustline Swap** is enabled, the XDR must be signed by both the user and the sponsor. #### โšก Gasless Trustline Flow When enabled, the transaction will include **all the operations required to perform the swap**, plus extra operations to: - ๐Ÿ’ฐ **Buy 0.5 XLM** โ€” The user purchases 0.5 XLM and sends it to the sponsor wallet. - ๐Ÿ›ก **Sponsor Trustline Reserve** โ€” The sponsor wallet covers the reserve required to open the userโ€™s trustline. > **Note:** The `gaslessTrustline` feature only works with a swap on the **Stellar Classic DEX**, and will be applied **only to the first swap for a specific user**. On mainnet, an EXACT_OUT quote against the Soroswap Aggregator sizes a fixed spend rather than an exact output: `amountIn` and `otherAmountThreshold` both become the amount that will actually be spent, and `amountOut` is the minimum you will receive, with any surplus delivered on top. SDEX quotes and every testnet quote are unaffected โ€” EXACT_OUT there still means an exact output behind a slipped maximum input. ## OpenAPI ````yaml POST /quote/build openapi: 3.0.0 info: title: Soroswap API description: >+ # ๐Ÿš€ Soroswap API **Soroswap.Finance** is both an **Automated Market Maker (AMM)** and a **DEX Aggregator** on the Stellar blockchain. It aggregates liquidity from Soroban DEXes (**Soroswap, Phoenix, Aqua and Comet(TBA)**), and the **Stellar Classic DEX** โ€” giving you **the best trade routes, liquidity tools, and real-time market data**. --- ## ๐Ÿ“‹ What You Can Do - ๐Ÿ”„ **Quote** โ€“ Get the best trade route between two assets with split-routing logic across AMMs and SDEX. - ๐Ÿงฑ **Build** โ€“ Generate and simulate unsigned transactions (XDR) for swaps or liquidity actions. - ๐Ÿš€ **Send** โ€“ Submit signed transactions via Soroban RPC or Horizon. - โšก **Gasless Trustlines** โ€“ Use `gaslessTrustline` in `/quote` to open trustlines for users without requiring them to hold XLM or deal with trustline setup themselves. - ๐Ÿ’ฐ **Platform Fees** โ€“ Add your own fee to user swaps with `platformFee`. - ๐Ÿ’ง **Liquidity** โ€“ Create LPs, add liquidity, remove liquidity. - ๐Ÿ’ฒ **Price** โ€“ Get real-time token prices. - ๐Ÿง  **Pools** โ€“ View detailed pool information for Soroswap AMM. ๐Ÿ“ฎ **[Downnload the Postman Collection here](https://drive.google.com/drive/folders/1G-LQYE2EojPWP1CSuuS_tDb9vjYbFR6E?usp=drive_link)** version: '1.0' contact: {} x-logo: url: https://links.paltalabs.io/soroswap-full.svg backgroundColor: '#0e0e0e' altText: Soroswap Logo href: https://soroswap.finance servers: [] security: [] tags: [] paths: /quote/build: post: tags: - Quote summary: Build description: > Builds an **unsigned XDR** for a quote. If **Gasless Trustline Swap** is enabled, the XDR must be signed by both the user and the sponsor. #### โšก Gasless Trustline Flow When enabled, the transaction will include **all the operations required to perform the swap**, plus extra operations to: - ๐Ÿ’ฐ **Buy 0.5 XLM** โ€” The user purchases 0.5 XLM and sends it to the sponsor wallet. - ๐Ÿ›ก **Sponsor Trustline Reserve** โ€” The sponsor wallet covers the reserve required to open the userโ€™s trustline. > **Note:** The `gaslessTrustline` feature only works with a swap on the **Stellar Classic DEX**, and will be applied **only to the first swap for a specific user**. On mainnet, an EXACT_OUT quote against the Soroswap Aggregator sizes a fixed spend rather than an exact output: `amountIn` and `otherAmountThreshold` both become the amount that will actually be spent, and `amountOut` is the minimum you will receive, with any surplus delivered on top. SDEX quotes and every testnet quote are unaffected โ€” EXACT_OUT there still means an exact output behind a slipped maximum input. operationId: SwapController_buildQuote parameters: - name: network required: false in: query description: Network on which the operation will be performed schema: enum: - testnet - mainnet type: string requestBody: required: true description: Data required to build the quote content: application/json: schema: $ref: '#/components/schemas/BuildQuoteDto' examples: regularExactIn: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10000000' amountOut: '9067253' otherAmountThreshold: '9067253' tradeType: EXACT_IN priceImpactPct: '0.50' platform: aggregator rawTrade: amountIn: '10000000' amountOutMin: '9067253' distribution: - protocol_id: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CD25MNVTZDL4Y3XBCPCJXGXATV5WUHHOWMYFF4YBEGU5FCPGMYTVG5JY - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV parts: 10 is_exact_in: true routePlan: - swapInfo: protocol: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CD25MNVTZDL4Y3XBCPCJXGXATV5WUHHOWMYFF4YBEGU5FCPGMYTVG5JY - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV percent: '100' to: GCSQJ7TCEVWXK2JZPTTTCJCVZZNMQXEJWVHIOCUAQHWNJSXKHX7OHVUW from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK summary: >- Data required to build the XDR for a regular EXACT_IN aggregator swap sdexExactOut: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10500000' amountOut: '10000000' otherAmountThreshold: '10500000' tradeType: EXACT_OUT priceImpactPct: '0.30' platform: sdex rawTrade: source_asset_type: credit_alphanum12 source_amount: '10000000' max_source_amount: '10500000' destination_asset_type: credit_alphanum12 destination_amount: '10000000' path: [] routePlan: - swapInfo: protocol: sdex path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV percent: '100' to: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK summary: Data required to build the XDR for a SDEX EXACT_OUT swap gaslessTrustlineExactIn: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10000000' amountOut: '8567253' otherAmountThreshold: '8467253' tradeType: EXACT_IN priceImpactPct: '0.50' platform: sdex gaslessTrustline: create rawTrade: source_asset_type: credit_alphanum12 source_amount: '10000000' destination_asset_type: credit_alphanum12 destination_amount: '9067253' min_destination_amount: '9000000' path: [] trustlineOperation: source_asset_type: credit_alphanum12 source_amount: '0.5000000' max_source_amount: '0.5100000' destination_asset_type: native destination_amount: '0.5000000' path: [] netAmount: '8567253' otherNetAmountThreshold: '8467253' trustlineInfo: trustlineCostAssetIn: '0.5000000' trustlineCostAssetOut: '0.5000000' routePlan: - swapInfo: protocol: sdex path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV percent: '100' to: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK sponsor: GDFRQKZH2F6QPZDW7YNWCV3H6FGUQZ3XAJS7XEZQVYZSQYB4SVPQXVYB summary: >- Data required to build the XDR for a gasless trustline EXACT_IN swap - sponsor lends 0.5 XLM for the trustline and user repays via output asset gaslessTrustlineExactOut: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10500000' amountOut: '10000000' otherAmountThreshold: '10700000' tradeType: EXACT_OUT priceImpactPct: '0.50' platform: sdex gaslessTrustline: create rawTrade: source_asset_type: credit_alphanum12 source_amount: '10000000' max_source_amount: '10200000' destination_asset_type: credit_alphanum12 destination_amount: '10000000' path: [] trustlineOperation: source_asset_type: credit_alphanum12 source_amount: '0.5000000' max_source_amount: '0.5100000' destination_asset_type: native destination_amount: '0.5000000' path: [] netAmount: '10500000' otherNetAmountThreshold: '10700000' trustlineInfo: trustlineCostAssetIn: '0.5000000' trustlineCostAssetOut: '0.0500000' routePlan: - swapInfo: protocol: sdex path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV percent: '100' to: GCSQJ7TCEVWXK2JZPTTTCJCVZZNMQXEJWVHIOCUAQHWNJSXKHX7OHVUW from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK sponsor: GDFRQKZH2F6QPZDW7YNWCV3H6FGUQZ3XAJS7XEZQVYZSQYB4SVPQXVYB summary: >- Data required to build the XDR for a gasless trustline EXACT_OUT swap - total input includes trustline setup cost sorobanSponsoredStep1: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10000000' amountOut: '9067253' otherAmountThreshold: '9067253' tradeType: EXACT_IN priceImpactPct: '0.50' platform: aggregator rawTrade: amountIn: '10000000' amountOutMin: '9067253' distribution: - protocol_id: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV parts: 10 is_exact_in: true to: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK sponsor: GDFRQKZH2F6QPZDW7YNWCV3H6FGUQZ3XAJS7XEZQVYZSQYB4SVPQXVYB summary: >- Step 1: Soroban sponsored transaction - API returns unsigned XDR for user to sign sorobanSponsoredStep2: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10000000' amountOut: '9067253' otherAmountThreshold: '9067253' tradeType: EXACT_IN priceImpactPct: '0.50' platform: aggregator rawTrade: amountIn: '10000000' amountOutMin: '9067253' distribution: - protocol_id: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV parts: 10 is_exact_in: true to: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK sponsor: GDFRQKZH2F6QPZDW7YNWCV3H6FGUQZ3XAJS7XEZQVYZSQYB4SVPQXVYB signedUserXdr: AAAAAgAAAABiSu3MsKtQvDuQO5i2b... summary: >- Step 2: Soroban sponsored transaction - Send user-signed XDR, API returns fee bump XDR for sponsor to sign withPlatformFee: value: quote: assetIn: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 assetOut: CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV amountIn: '10000000' amountOut: '9067253' otherAmountThreshold: '9067253' tradeType: EXACT_IN priceImpactPct: '0.50' platform: aggregator platformFee: feeBps: 50 feeAmount: 50000 rawTrade: amountIn: '10000000' amountOutMin: '9067253' distribution: - protocol_id: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV parts: 10 is_exact_in: true routePlan: - swapInfo: protocol: soroswap path: - >- CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 - >- CDTKPWPLOURQA2SGTKTUQOWRCBZEORB4BWBOMJ3D3ZTQQSGE5F6JBQLV percent: '100' to: GCSQJ7TCEVWXK2JZPTTTCJCVZZNMQXEJWVHIOCUAQHWNJSXKHX7OHVUW from: GBQJ4HBCQHJQKSKNT3JRKC5VKA3QJUXBVFWIVSMHKPQSJ7XP2IXTCAAK summary: >- Data required to build the XDR for a quote whose platform fee came from the partner rate responses: '200': description: XDR built successfully content: application/json: schema: type: object properties: xdr: type: string example: >- AAAAAgAAAAB8shYDi1JO9x2/3jMeVzK2IGtrsFVWLCL4uHRJf+YPyAAAA+gCzi7HAAAApgAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAGAAAAAAAAAABc12cL... description: Transaction XDR ready for signing and execution '400': description: Invalid quote data or missing required fields '409': description: The fee rate changed since the quote was issued; request a new quote '428': description: Precondition Required - Multi-step action needed content: application/json: schema: oneOf: - title: 'Step 1: User Signature Required' type: object properties: message: type: string example: User signature required for sponsored transaction action: type: string example: SIGN_USER_TRANSACTION actionData: type: object properties: xdr: type: string example: AAAAAgAAAAB8shYDi1JO9x2... step: type: number example: 1 totalSteps: type: number example: 2 description: type: string example: >- Sign the transaction with the user wallet and send back the signed XDR - title: 'Step 2: Sponsor Signature Required' type: object properties: message: type: string example: Sponsor signature required for fee bump transaction action: type: string example: SIGN_SPONSOR_TRANSACTION actionData: type: object properties: xdr: type: string example: AAAABQAAAABiSu3MsKtQvDuQO5i2b... step: type: number example: 2 totalSteps: type: number example: 2 description: type: string example: >- Sign the fee bump transaction with the sponsor wallet components: schemas: BuildQuoteDto: type: object properties: quote: type: object description: The quote to build the XDR for from: type: string description: The wallet address that will send the funds to: type: string description: >- The wallet address that will receive the funds. If Gasless Trustline Swap is enabled, this is the wallet address must be the same as the from address (hence, don't provide this parameter) referralId: type: string description: >- Ignored. Fee destinations are no longer caller-supplied; the value you send is recorded so Soroswap can propose your payout address. sponsor: type: string description: >- The wallet address that will sponsor the transaction. Only required for Gasless Trustline Swap and Soroban sponsored transactions signedUserXdr: type: string description: >- The signed transaction XDR from Step 1 of Soroban sponsored transactions. Required for Step 2 when sponsor is provided for non-SDEX platforms. required: - quote ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.