# Fast by Circular

> Land your Solana transactions in the current slot, 0-slot delay, and earn back 65% of the value they leak, paid in SOL.

Source: https://landfast.io · Docs: https://docs.circular.fi/api/fast

## What it is

Fast is Circular's transaction broadcast service for Solana. You send a raw
signed transaction to a single endpoint; Fast races it over several independent
routes at once — Solana nodes, dedicated SWQoS connections, UDP routes, Jito,
Harmonic, Rakurai and private validator deals — so it lands in the slot that is
already open rather than the next one.

Your transaction is never modified, never delayed, and never waits on anything.

## The two things it does

1. **0-slot landing.** Solana slots last 200ms. A standard RPC usually submits
   too late and your transaction is queued for the next slot. Fast propagates
   wide enough to land in the current one — zero slots of delay.

2. **65% MEV cashback.** A trade moves a pool and leaves value on the table. On
   any other RPC a third party captures it and keeps all of it. Fast captures it
   on your own transaction, after it lands, and returns 65% in SOL to the
   `cashbackAddress` you passed in. The remaining 35% covers execution and
   validator costs. Nothing to claim, no extra call.

## Getting started

- Endpoint: `https://fast.circular.fi/transactions`
- Auth: `x-api-key` header
- API keys: https://circular.fi
- Full reference: https://docs.circular.fi/api/fast

## More

- [Pricing](https://landfast.io/pricing.md)
- [API](https://landfast.io/api.md)
- [FAQ](https://landfast.io/faq.md)