TopazTOPAZDocs

Trading

Swaps & Routing

Most swaps on Topaz are a one-click experience — pick tokens, type the amount, accept the rate, sign. This page is for everyone who wants to understand what's happening underneath: routing across pool types, slippage, price impact, and MEV protection.

The basic flow

  1. 1Open app.topazdex.com/swap and connect a BNB Chain wallet.
  2. 2Pick the input and output tokens. The app reads your wallet balance for the input.
  3. 3Type the amount you want in (exact-in) or out (exact-out). The app quotes the other side.
  4. 4Review: rate, price impact, route, fees on each hop, and the minimum-out figure after slippage.
  5. 5If this is the first time you're spending the input token from your wallet on Topaz, approve once. Then Swap.
ℹTwo router contracts under the hood
v2-style pools route through the Topaz Router. Slipstream pools route through Slipstream's SwapRouter. The frontend uses a mixed-route quoter that considers both, picks the cheapest end-to-end path, and submits a single transaction. You don't pick which — you just see the chosen route.

Exact-input swaps

Every swap through the Topaz app is an exact-input swap: "I'm spending exactly X token A, give me as much token B as possible." The output amount is variable; the transaction fails if the output drops below your minimum-out (your slippage tolerance).

ℹExact-output is a contract-level feature
The underlying SwapRouter and Router contracts also support exact-output swaps ("spend whatever it takes to get exactly Y"), but the Topaz frontend doesn't expose this — only exact-input. Integrators who need exact-output can call the contracts directly; see the Integration Guide.

Slippage protection

Between the moment you sign and the moment your transaction is included, the price can move. Slippage tolerance is your guardrail: the swap reverts if the output drops below (1 − slippage) × quote (for exact-in) or input exceeds (1 + slippage) × quote (for exact-out).

  • ✓Default 0.5% works for most stablecoin and major-pair swaps.
  • ✓Set 0.1% on tight stable swaps if you want a hard cap on cost.
  • ✓Long-tail tokens or shallow pools may legitimately need 1–3%. If you find yourself raising slippage above 5%, reconsider the trade — you're probably the source of most of the price impact.
  • ✓Watch for transfer-fee tokens (tokens that deduct on transfer). Their minimum-out math is special; the router has fee-on-transfer-aware paths.
⚠High slippage is a sandwich invitation
A 5%+ slippage setting tells searchers there's 5% of profit they can extract from a sandwich attack on your trade. Lower slippage = harder to sandwich = better fill on average. Only raise it if the trade legitimately won't execute otherwise.

Price impact

Slippage tolerance is your guardrail. Price impactis the actual cost: how much your trade moves the pool's price away from the current quote. A 0.05% price-impact swap barely nudges the curve; a 5% price-impact swap leaves the pool priced 5% worse for the next trader, and you took the cost of that move.

The app shows price impact in red when it exceeds a threshold (typically 1%). If you see that warning, options are:

  • ✓Break the trade into smaller chunks — but be aware each one has gas cost.
  • ✓Wait for the pool to fill if you're trading against thin liquidity (or place a different order earlier in the day).
  • ✓Check if a different route gives better impact — sometimes routing through a stablecoin or a different fee tier is much better than the direct pool.
  • ✓For very large trades, contact the project — there may be OTC desks or aggregators specialized for size.

Routing across v2 and Slipstream

A given pair on Topaz might have multiple pools: a v2 volatile pool, a Slipstream tick-100 pool, a Slipstream tick-200 pool, and so on. The routing engine evaluates each and may even split a trade across pool types in a single transaction — the contract that supports this is the MixedRouteQuoterV1.

For multi-hop trades, the router uses common intermediates: WBNB, USDT, USDC, BUSD. A swap from a long-tail token to another long-tail token will typically route through one of these to reach deep liquidity in both directions.

✨The chosen route is auditable
The app surfaces the chosen route on the swap confirmation. You can see which pools are involved, which fee tiers are used, and decide whether to take it. If you don't like the route, try a different output token or smaller amount and recheck.

MEV and front-running

BNB Chain has an active MEV (maximal extractable value) marketplace. Searchers monitor the mempool, looking for trades with high slippage tolerance they can sandwich. Topaz itself can't hide your transaction, but you can defend yourself:

  • ✓Set slippage as low as the trade allows.
  • ✓For large trades, use a private RPC (BloXroute, Merkle, or your wallet's MEV-protected mode if available) so the transaction reaches the block builder without hitting the public mempool.
  • ✓Split a very large trade across blocks — sandwich attacks compose with single trades.
  • ✓Avoid the deadline being too far in the future. Most routers default to 10–30 min; that's fine.

Fees you actually pay

For each hop, the pool's swap fee (e.g. 0.05% on a stable pool, 0.30% on a volatile pool) is taken from the input amount and accrued to that pool. On Topaz, those fees go to veTOPAZ voters who voted for the pool — not to the protocol treasury. On a two-hop swap A → B → C, you pay both pools' fees.

On top of pool fees, you pay BNB gas to execute the transaction — usually a few cents at typical BSC gas prices. Approval transactions (one-time per token, per spender contract) add a tiny first-time cost.

Want the full fee story? Read Pool Fees.

Continue reading

Pool Fees →

Default fees, dynamic fees, unstaked fees, and where the fees flow.

AMM & Pool Types →

Stable vs volatile vs concentrated — pick the right pool for the pair.

Integration Guide →

Build a router or aggregator that swaps through Topaz programmatically.

Contracts →

Router, SwapRouter, QuoterV2, and MixedRouteQuoterV1 addresses.