# Transaction pool

The transaction pool buffers incoming transactions, verifies them, and produces a packable set for block generation. It manages per-sender nonce order and supports two "spaces" (native and EVM).

## Main components

* `TransactionPool` - public API, ties to data manager and executed state.
* `TransactionPoolInner` - core data structures and packing logic.
* `DeferredPool` - per-sender nonce pools plus a packing pool.
* `PackingPool` - randomized packing algorithm with gas/price weighting.
* `AccountCache` - keeps nonce and balance hints for validation.

## Intake and validation flow

1. RPC/P2P submits a `SignedTransaction`.
2. `VerificationConfig` and `Machine` checks validate chain id, gas bounds, epoch bounds, and signature.
3. Transaction is inserted into the sender's `NoncePool`.
4. Ready contiguous nonces are mirrored into the `PackingPool`.

## Packing model

* Transactions are grouped per sender into `PackingBatch` objects to preserve nonce order.
* `PackingPool` is a treap-based structure that supports randomized sampling.
* Sampling considers block gas limits, block size limits, and minimum gas price.
* For EIP-1559 style pricing, the pool estimates the next base price using `compute_next_price` and adjusts the packing gas limit accordingly.

## Space-aware packing

Mazze uses `SpaceMap` for dual spaces:

* Native space is always packable.
* EVM space is packable only after the configured transition height.

The pool tracks gas usage per space and enforces per-space limits during block validation.

## Key source files

* `crates/mazzecore/core/src/transaction_pool/mod.rs`
* `crates/mazzecore/core/src/transaction_pool/transaction_pool_inner.rs`
* `crates/mazzecore/packing-pool/src/pool.rs`
* `crates/mazzecore/packing-pool/src/packing_batch.rs`


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.mazze.io/architecture/transaction-pool.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.