SVM SDK Examples

These examples show how to create and trade Doppler launches on Solana.

Fee settings

Each Solana launch chooses a standard trading fee when it is created. The current allowed range is 0.10%-5.00%. The fee is paid in the token being sold: buys generate fees in SOL or USDC, while sells generate fees in the launched token.

Doppler receives 7.50% of each collected trading fee, and the remainder goes to the beneficiaries selected for the launch. This is a share of the fee, not an additional fee on the trade. For example, with a 1% trading fee, Doppler receives 0.075% of the trade.

A launch's fee settings are saved when it is created, so later changes to the network settings apply only to new launches. A launch may also use a fee that decreases over time. It can begin anywhere from 0% to 100%, including above the standard fee range, but it can never reduce the fee below the launch's standard fee. See Dynamic fee launch.

Cosigning

Cosigning is an optional transaction approval layer for a launch. While it is enabled, each swap must include a signature from an approved cosigner before Doppler accepts it. The cosigner does not take custody of the user's tokens or submit the trade for them; it only confirms that the transaction is allowed under the launch's trading policy.

A cosigning gate can end at a chosen time or remain active indefinitely, and it works with either standard or time-based fees. Once an expiring gate ends, trading continues normally without approval. Creating a launch and claiming fees do not require cosigning.

The standard SDK selects a cosigner already approved by Doppler; supplying an address does not register a new cosigner. Teams interested in cosigning, running their own approval service, or discussing a custom setup can contact [e-mail].

• Launch - create a standard Solana launch.

• Dynamic fee launch - create a launch with a decaying swap fee schedule, optionally combined with cosigner gating.

• Swap - swap against a Solana CPMM pool.

• Launch, monitor, and e2e - create, monitor, trade, and migrate a launch end to end.