> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lasersell.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Build Buy Transaction
> Build an unsigned buy transaction to swap SOL or USD1 for tokens via one of the supported DEXs.
The response contains a base64-encoded unsigned `VersionedTransaction`. Sign it locally with your keypair and submit it to the network.
If you plan to track this buy with the Exit Intelligence Stream, you **must** connect the stream **before** submitting the buy transaction. The stream detects new positions by observing on-chain token arrivals in real time. If the stream is not connected when the buy lands, the position will not be tracked and no exit signals will be generated for it.
Exactly one of `amount` or `amount_in_total` must be provided. `amount` is automatically converted to atomic units based on the `input` asset (SOL: 10^9, USD1: 10^6).
## SDK Examples
```typescript TypeScript theme={null}
import { ExitApiClient, type BuildBuyTxRequest } from "@lasersell/lasersell-sdk";
const client = ExitApiClient.withApiKey("YOUR_API_KEY");
const request: BuildBuyTxRequest = {
mint: "TOKEN_MINT_ADDRESS",
user_pubkey: "YOUR_WALLET_PUBKEY",
amount: 0.1, // 0.1 SOL
slippage_bps: 2_000,
};
const response = await client.buildBuyTx(request);
console.log("Unsigned tx (base64):", response.tx);
```
```python Python theme={null}
from lasersell_sdk.exit_api import ExitApiClient, BuildBuyTxRequest
client = ExitApiClient.with_api_key("YOUR_API_KEY")
request = BuildBuyTxRequest(
mint="TOKEN_MINT_ADDRESS",
user_pubkey="YOUR_WALLET_PUBKEY",
amount=0.1, # 0.1 SOL
slippage_bps=2_000,
)
response = await client.build_buy_tx(request)
print("Unsigned tx (base64):", response.tx)
```
```rust Rust theme={null}
use lasersell_sdk::exit_api::{ExitApiClient, BuildBuyTxRequest};
let client = ExitApiClient::with_api_key("YOUR_API_KEY");
let request = BuildBuyTxRequest {
mint: "TOKEN_MINT_ADDRESS".into(),
user_pubkey: "YOUR_WALLET_PUBKEY".into(),
amount: Some(0.1), // 0.1 SOL
slippage_bps: 2_000,
..Default::default()
};
let response = client.build_buy_tx(&request).await?;
println!("Unsigned tx (base64): {}", response.tx);
```
```go Go theme={null}
import lasersell "github.com/lasersell/lasersell-sdk/go"
client := lasersell.NewExitAPIClientWithAPIKey("YOUR_API_KEY")
amount := 0.1 // 0.1 SOL
resp, err := client.BuildBuyTx(ctx, lasersell.BuildBuyTxRequest{
Mint: "TOKEN_MINT_ADDRESS",
UserPubkey: "YOUR_WALLET_PUBKEY",
Amount: &amount,
SlippageBps: 2_000,
})
if err != nil {
log.Fatal(err)
}
fmt.Println("Unsigned tx (base64):", resp.Tx)
```
## Error Responses
See [Error Handling](/api/exit-api/error-handling) for the full error envelope specification and retryable error logic.
## OpenAPI
````yaml POST /v1/buy
openapi: 3.1.0
info:
title: LaserSell API
version: 1.0.0
description: >
The LaserSell API builds unsigned Solana transactions for buying and selling
tokens across supported DEXs.
All transactions are non-custodial: the API returns unsigned
`VersionedTransaction` payloads that you sign locally with your own keypair.
Supported markets: Pump.fun, PumpSwap, Raydium (CPMM, Launchpad), Meteora
(DBC, DAMM v2).
servers:
- url: https://api.lasersell.io
description: Production
security:
- apiKey: []
tags:
- name: Trading
description: Build unsigned buy and sell transactions.
- name: Account
description: Account details and trade history.
- name: Wallets
description: Wallet registration for the Exit Intelligence Stream.
paths:
/v1/buy:
post:
tags:
- Trading
summary: Build Buy Transaction
description: >
Build an unsigned buy transaction to swap SOL or USD1 for tokens via one
of the supported DEXs.
The response contains a base64-encoded unsigned `VersionedTransaction`.
Sign it locally with your keypair and submit it to the network.
operationId: buildBuyTx
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/BuildBuyTxRequest'
responses:
'200':
description: Unsigned buy transaction built successfully.
content:
application/json:
schema:
$ref: '#/components/schemas/BuildTxResponse'
'400':
description: >-
Bad request (invalid parameters, invalid mint, or unsupported token
program).
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/ErrorResponse'
- $ref: '#/components/schemas/UnsupportedResponse'
'401':
description: Unauthorized. Missing or invalid API key.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
'404':
description: Unsupported market or mint not indexed yet.
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/UnsupportedResponse'
- $ref: '#/components/schemas/NotIndexedResponse'
'422':
description: Valid request but no viable route found.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
'429':
description: Rate limited. Back off and retry.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
'500':
description: Internal server error.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
components:
schemas:
BuildBuyTxRequest:
type: object
required:
- mint
- user_pubkey
- slippage_bps
properties:
mint:
type: string
description: Token mint address to buy (base58).
example: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v
user_pubkey:
type: string
description: Your wallet public key (base58).
example: 9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM
amount:
type: number
description: >
Human-readable amount to spend (e.g., `0.1` for 0.1 SOL, `10.0` for
10 USD1).
Mutually exclusive with `amount_in_total`. Exactly one of `amount`
or `amount_in_total` must be provided.
example: 0.1
amount_in_total:
type: integer
description: >
Amount to spend in input-asset atomic units (e.g., lamports for
SOL).
Mutually exclusive with `amount`. Exactly one of `amount` or
`amount_in_total` must be provided.
example: 100000000
slippage_bps:
type: integer
description: Maximum slippage tolerance in basis points (e.g., `2000` = 20%).
example: 2000
input:
type: string
enum:
- SOL
- USD1
default: SOL
description: Input asset.
mode:
type: string
enum:
- fast
- secure
default: fast
description: Routing mode hint.
send_mode:
type: string
enum:
- helius_sender
- astralane
- rpc
description: Transaction send mode.
tip_lamports:
type: integer
description: Optional priority fee tip in lamports.
partner_fee_recipient:
type: string
description: Partner fee recipient wallet (base58 pubkey).
partner_fee_bps:
type: integer
description: >-
Partner fee in basis points (max 50 = 0.5%). Mutually exclusive with
`partner_fee_lamports`.
maximum: 50
partner_fee_lamports:
type: integer
description: >-
Partner fee as flat SOL lamports (max 50,000,000). Mutually
exclusive with `partner_fee_bps`.
maximum: 50000000
BuildTxResponse:
type: object
required:
- tx
properties:
tx:
type: string
description: >-
Base64-encoded unsigned Solana `VersionedTransaction`. Sign this
locally with your keypair before submitting.
example: AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...
route:
type: object
description: Routing metadata.
properties:
market_type:
type: string
description: DEX used for this route.
example: pumpswap
pool_id:
type: string
description: Pool address used.
debug:
type: object
description: Debug information (included when available).
ErrorResponse:
type: object
required:
- error
properties:
error:
type: string
description: Human-readable error message.
example: invalid mint address
UnsupportedResponse:
type: object
required:
- status
- reason
- message
properties:
status:
type: string
const: unsupported
reason:
type: string
enum:
- no_route
- invalid_mint
- unsupported_token_program
description: Machine-readable reason code.
message:
type: string
description: Human and AI-readable explanation.
example: >-
No supported market found for this mint. Supported DEXs: PumpSwap,
Raydium (CPMM, Launchpad), Meteora (DBC, DAMM v2), Pump.fun.
NotIndexedResponse:
type: object
required:
- status
- mint
- reason
properties:
status:
type: string
const: not_indexed
mint:
type: string
description: The mint address that is not yet indexed.
reason:
type: string
example: mint not indexed yet; try again shortly
securitySchemes:
apiKey:
type: apiKey
in: header
name: x-api-key
description: >-
Your LaserSell API key. Obtain one from the [LaserSell
dashboard](https://www.lasersell.io).
````