> For the complete documentation index, see [llms.txt](https://node1.gitbook.io/node1-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://node1.gitbook.io/node1-docs/solana/fast-landing/batch-api.md).

# Batch API

Send up to 4 signed transactions in one request. They are delivered as a bundle: executed in the order given, all in the same block, all-or-nothing. If any of them fails, none of them land. Use it for multi-step trades that must not be split.

* Endpoint: `POST /v2/batch` on any region host (`https://fra.node1.me/v2/batch`)
* Header: `api-key: $APIKEY`
* Body: raw bytes, format below. No JSON, no base64.
* 1 to 4 transactions, each a fully signed serialized transaction (the same bytes you would base64-encode for `sendTransaction`), 1232 bytes max each (4096 for v1 transactions).
* Tip: the sum of transfers to the Node1 tip accounts across the whole batch must reach your plan's minimum tip. The tip can sit in any one of the transactions.
* Rate limit: a batch counts as 1 against your TPS.

## Body format

```
offset      size        field
0           1           count            number of transactions, 1..4
1           2 * count   lengths          length of each transaction, u16 little-endian, in order
1+2*count   sum(len)    transactions     the serialized transactions, concatenated in order

The body must be exactly 1 + 2*count + sum(lengths) bytes.
```

## Response

HTTP 200, JSON with the signatures in the same order as the request:

```json
{"jsonrpc":"2.0","id":1,"result":["<sig of tx 0>","<sig of tx 1>"]}
```

Anything else is an error. The HTTP status is the code, the body is a plain-text message:

```
401   Invalid Api-Key / Not Found api-key
429   Exceed Rate Limit: N per second
605   Batch Decode Error: ...           bad body layout, or a transaction that cannot be decoded
606   Tip Instruction Not Found         no transfer to a Node1 tip account in the batch
607   Please add a minimum tip of N lamports (batch total)
```

## Example: curl

The body has already been written to a file.

```bash
curl -X POST "https://fra.node1.me/v2/batch" \
  -H "api-key: $APIKEY" \
  -H "Content-Type: application/octet-stream" \
  --data-binary @batch.bin
```

## Example: Rust

This Rust snippet assumes that `api_key` and `txs` are supplied by your application. `txs` contains locally signed, serialized transactions; replace all example placeholders before running.

```rust
// Cargo.toml: reqwest = { version = "0.12", features = ["blocking"] }
use reqwest::blocking::Client;

fn batch_body(txs: &[Vec<u8>]) -> Vec<u8> {
    let mut body = vec![txs.len() as u8];
    for tx in txs {
        body.extend_from_slice(&(tx.len() as u16).to_le_bytes());
    }
    for tx in txs {
        body.extend_from_slice(tx);
    }
    body
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // signed transactions, in execution order
    // let txs = vec![bincode::serialize(&tx1)?, bincode::serialize(&tx2)?];
    let resp = Client::new()
        .post("https://fra.node1.me/v2/batch")
        .header("api-key", api_key)
        .body(batch_body(&txs))
        .send()?;
    println!("{} {}", resp.status(), resp.text()?);
    // 200 {"jsonrpc":"2.0","id":1,"result":["5oBk...","3SFd..."]}
    Ok(())
}
```


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