Product whitepaper · v1.14
Fyll: the trading layer that sits where you already trade.
Fyll appears beside the pages traders already use, routes the same trade for more of the token, and gives back value their wallets have been sitting on.
September 2026 · Reading time 12 minutes
In one page
A memecoin trader’s day is spent on a handful of sites—a launchpad, a chart, a terminal. The trade happens in whatever box that site provides. That box takes a cut, controls the slippage and gives nothing back. Fyll replaces the box without moving the trader.
- It appears where they are. On five trading sites, the panel opens with the token on screen already loaded.
- It routes the same trade for more. The difference against the selected venue is shown before confirmation, in tokens rather than percentages.
- It gives value back. Fyll finds refundable Solana deposits and clears dust balances.
- It keeps the record. Portfolio, history and real profit and loss sit beside claims and sweeps.
- It never holds anything. Every transaction is checked, then signed in the user’s wallet.
The problem
Three costs traders learned to ignore.
The cut is invisible.
A venue’s take sits inside its quote. Knowing the difference requires pricing the same trade elsewhere, which almost nobody does mid-trade.
Slippage is not theirs.
A venue that fixes slippage decides how much movement is acceptable between the price shown and the price received.
Value goes unseen.
Refundable Solana deposits and long tails of dust remain in wallets because trading interfaces have no reason to surface them.
Everything Fyll does
Trade beside the page
A panel on five trading sites, opening with the right token loaded.
More of the token
The same swap, routed for more, with the difference shown before signing.
Slippage you control
Auto, 0.5%, 1% or a number you set. Nothing fills below your floor.
Six chains
Solana, Base, BNB Chain, Ethereum, Monad and Robinhood Chain.
Pay from another chain
Buy an EVM token with SOL or USDC held on Solana, in one flow.
Gas without the bridge
Top up a gas-empty EVM wallet with SOL so a first trade is possible.
Reclaim locked SOL
Close empty token accounts and take the deposits back.
Claims with no gas
A wallet with zero SOL can still claim when the economics make sense.
Dust sweeps
Sell the tail of small balances; on EVM, all of them in one transaction.
Real PnL
Entry, current price, hold time, realised and unrealised, per position.
Points and referrals
Season 1 scoring and a referral that rewards both sides.
One-tap sharing
A card drawn for a trade and published with the post automatically.
Five front doors
One engine. Your wallet signs.
The same panel runs beside Fomo, pump.fun, DexScreener, GMGN and Padre; as a web app; on a phone; inside a wallet browser; and through a handoff from the web app to the extension.
Finding the token for you
Fyll reads the contract address from the page rather than asking the trader to paste it. Each supported site has an adapter for its URL, header, copy control and metadata. Every detection carries a confidence score and evidence, so a guess never silently becomes a trade.
Navigation observers handle single-page sites that change token without a reload. A direct ?token= link and the in-panel picker also resolve addresses across supported chains. An earlier clipboard watcher was removed: invisible clipboard access was not worth the convenience.
Trading
Quotes refresh while the panel is visible and pause when it is not, keeping the number current without burning quota on an idle tab. The amount a trader typed is never wiped by a refresh.
Slippage stays explicit.
Choose Auto, 0.5%, 1%, or a custom value. Auto adapts within a cap; a custom floor is honoured exactly. A route that cannot respect it is refused rather than quietly widened.
Some trades should not happen.
Fyll blocks trades that would leave a wallet unable to pay network fees, says when no route exists, and omits a comparison when it cannot support the claim.
Six chains. One panel.
Solana, Base, BNB Chain, Ethereum, Monad and Robinhood Chain each keep their own vetted contracts, gas reserve and stable pricing asset. A trader holding SOL or USDC on Solana can buy on an EVM chain in one priced flow. An empty EVM wallet can receive enough destination gas to make its first trade possible.
The comparison line
Under the receive amount, Fyll shows how much more token the route returns than the venue the trader selected. Published venue rates are stored with their source and reading date. If a venue publishes nothing, the panel says so and uses the lowest reported rate—erring against Fyll.
Reclaiming value
Locked SOL
Every empty SPL token account on Solana holds a refundable rent deposit. Fyll finds those accounts, shows what closing them returns, and closes them in batches. The amount shown is the amount that should arrive.
Claims with no gas
When a wallet cannot cover the claim fee and the waiting deposits are worth several times more, Fyll can send the small network amount first. If that prerequisite fails, nothing else proceeds.
Dust, swept
On Solana, uneconomic token tails can be bundled instead of sold one by one. On EVM chains, supported wallets can approve a shared permit and sweep the selected balances in one transaction.
Portfolio, history and real PnL
Positions combine current holdings with their actual trade record: entry, current price, hold time, realised and unrealised profit and loss. Claims and sweeps remain in the same history rather than disappearing into a separate tool.
Points and referrals
Season 1 measures settled on-chain activity: volume, streaks, active days, claims and sweeps. Interface activity alone is worth nothing. Referrals reward both sides from what Fyll earns, with consent established through a wallet signature.
Non-custodial by design
Three checks before submission.
- 01
Simulate
A transaction expected to fail is refused before the wallet sees it.
- 02
Read the bytes
The panel rejects instructions that could move value outside the reviewed trade.
- 03
Match the result
The signed transaction must retain the same payer, signer, accounts and instruction order.
Fyll never holds a user’s assets, asks for a private key, or takes custody. Every transaction ends in the trader’s wallet.
What is next
- Gas-free EVM swaps. Sell without first holding the destination gas coin.
- Chrome Web Store. Remove the final installation friction.
- More comparison venues. Each with a published rate and reading date.
- Wallet-native batching. One prompt for EVM sweeps across more wallets.
The market
Fyll competes for the interface.
Fyll does not compete with a blockchain or liquidity pool. It competes with the wallet, terminal or launchpad that chooses the route, sets slippage and takes the cut.
The source snapshot, dates and methodology are documented in the supplied PDF and notes below. Market volume changes continuously.
Illustrative model
Base case: one percent of interfaces in two years.
The model starts at 0.02% of the measured interface market and compounds at approximately 18.5% monthly for 24 months. It holds the market flat and applies 0.30% revenue to routed volume.
If the share lands elsewhere
This is a planning model, not a forecast or promise. Real adoption, market volume, pricing and costs can differ materially.
Open the original model and assumptionsNotes and sources
Market figures are snapshots, not live totals. The September 2026 edition uses the sources, dates, venue-rate methodology and assumptions listed in the original document. Product availability and chain support may change during beta.
Fyll is non-custodial software, not financial advice. Crypto trading carries risk. Fyll is not affiliated with Fomo, pump.fun, DexScreener, GMGN, Padre or the other interfaces discussed.