The gap between the quote and the fill

Every swap on Solana settles at a price the interface only estimated. SolSpread takes that gap apart: the pool fee you always pay, the price impact your own size creates, and the movement that happens while the transaction is in flight.

We define the term, show the arithmetic, then say what to do about it. Numbers here are either protocol facts or clearly labelled illustrative examples.

The console linked above is operated by a third party and is included because readers of an execution desk usually want to see what execution software does with routing and order splitting.

Anatomy of one illustrative fill

Pool reserves5,000 SOL / 250,000,000 TKN
Mid price50,000 TKN per SOL
Order size100 SOL (2% of reserve)
Pool fee-0.25%
Price impact-1.96%
Effective price48,899 TKN per SOL
Total gap vs mid-2.20%

Illustrative arithmetic on a constant-product pool, not observed market data. The full derivation is in slippage explained.

Three costs sit inside every swap

They are usually reported as one percentage, which is why traders keep applying the wrong fix. Each one has its own driver and its own lever.

The spread you are quoted

buy quote - sell quote at one instant

An AMM has no order book, so the spread shows up as the difference between what you can buy at and sell at in the same moment, driven mostly by the pool fee tier.

Separate the three terms

The impact you create

impact = in / (x + in)

On a constant-product pool your fee-free price impact is exactly your input divided by the post-trade input reserve. Size relative to that reserve is the whole story.

See how splitting changes it

The fees you pay per attempt

base + priority + pool fee x hops

Lamport costs are flat per attempt, so they dominate small orders and disappear on large ones. Failed attempts pay them too, which is a cost most reports omit.

Build the full cost sheet

Featured explainers

Four pieces that cover the questions traders ask most often about fills that did not match the quote.

01

Slippage on Solana explained

Slippage is the difference between the price you were quoted and the price you got. Three separate things produce it, and only one of them is the tolerance slider.

Filed in Execution basics

02

Setting slippage tolerance

Tolerance is a two-sided cost: too low and the transaction reverts, too high and you fund someone else. A decision table by pool depth and urgency.

Filed in Execution basics

03

Quote vs fill: why they differ

The lifecycle of a quote from request to landed transaction, where it goes stale, and a symptom-to-cause diagnostic table for bad fills.

Filed in Execution basics

04

Aggregators vs direct pool swaps

Direct pool swaps are cheaper in compute and simpler to reason about. Aggregation wins on price for size. A comparison table and a decision checklist.

Filed in Routing

Three sections, one subject

Definitions first, then how orders are routed, then how to price and measure what the routing cost you.

Execution basics

Definitions and mechanics. What a quote is, what moves it, and which parts of the gap between quote and fill you actually control.

Open the section

Routing

How a router turns one order into several fills, why splitting lowers price impact, and what a longer route costs you in fees and failure risk.

Open the section

Cost model

The full cost stack of a swap, the risks that inflate it, and the measurement discipline that tells you whether a change helped.

Open the section

Worked examples you can check

Every figure below is arithmetic we performed on stated assumptions. None of it is a measurement of a live market, and each example states its inputs so you can redo it with your own.

2.20%

Total gap against mid on a 100 SOL order placed against a pool holding 5,000 SOL, split into 1.96% impact and 0.25% fee.

See the five-size table
60 SOL

One order priced into a single pool and then across two, three and four pools, including the case where the fourth leg makes the fill worse.

Compare the split rows
0.42 / 0.55

Two execution paths with different price gaps and different landing rates, showing why cost per unit filled decides and price alone does not.

Read the comparison method

When execution stops being a setting and becomes an operations problem

One swap is a decision. A hundred swaps across several venues, sized against changing depth and scheduled over hours, is an operation: quotes have to be refreshed, clips sized against current reserves, failures retried, and every attempt logged if the result is going to mean anything. That is the point at which people stop clicking and start running software.

On the other side of this link is a third-party console that routes orders across Solana venues and runs the clip-by-clip work automatically. It is listed here because it is the practical alternative to doing the split by hand, not because this desk can verify any particular outcome from it.

Quotesrefreshed per clip
Sizeset against live depth
Failuresretried and logged
Venuesrouted across Solana
Explore Solana trading tools

External site. SolSpread has no operational relationship with the venues or tools it describes, and nothing on this page is advice to trade.

How the numbers here are produced

An execution desk that invents data is worse than useless, because the reader cannot tell which half is real. Our rule is simple: every number is either checkable protocol behaviour or arithmetic we show our work for.

Protocol facts

Constants that anyone can verify against documentation or the chain: nine decimals on SOL, a slot target near 400 milliseconds, a base fee of 5,000 lamports per signature, a blockhash valid for 150 slots, the constant-product invariant.

Illustrative arithmetic

Pool sizes, order sizes and fee tiers chosen by us to make a mechanism visible. Every such table is captioned as illustrative and states its assumptions so the calculation can be reproduced or replaced with your own inputs.

What you will not find

No observed market statistics, no performance claims, no review scores, no case studies with invented profit figures, no named traders. If we cannot show how a number was produced, it does not go on the page.

Who writes this

Everything is published under The SolSpread Desk rather than a persona. The sourcing rules, the correction process and the limits of what this desk can verify are set out in the editorial policy.