Programmable Economics

NorthStar sessions are gasless by default on devnet — but that's just one configuration of a fully-programmable fee market. Operators set their own economics per session: any fee schedule, any token, any revenue split.

What's configurable per session

Every session opens with a FeeStructure parameter that decides:

• Fee level — gasless, sub-cent, or any amount the operator chooses.

• Fee token — SOL, USDC, the operator's own SPL token, or no token at all.

• Revenue split — the slice that goes to the grid operator vs. the protocol.

• Per-instruction overrides — different fee bands per workload (place_intent vs. settle_intent vs. data feeds).

The default zero_fee_structure() is a useful starting point for marketing demos and developer-experience flows. Production grids will run their own.

Why programmable fees matter

Three direct consequences:

1. Builders set their own runway. A team running a market-data feed can charge per-read in their own token; a privacy-focused DeFi venue can charge premium fees for sealed-bid auctions; an agent-sandbox operator can subsidize the agent's transactions to remove user friction.

2. Aggregators and wallets become operators. A wallet that opens grids on behalf of users captures a share of the fees on every transaction in that grid. New revenue stream, no separate validator infrastructure.

3. No protocol-level rent. The protocol's take is a parameter, not a fixed tax. Operators can run thin margins for high-volume workloads or fat margins for premium ones.

API surface

The FeeStructure is a parameter on the Portal program's OpenSession instruction. The full schema lives in the SDK reference. A typical opening for a custom-fee grid looks like:

import { NorthStarSDK, FeeStructure } from "@sonicsvm/northstar-sdk";

await sdk.openSession({
  gridId,
  ttlSlots: 86_400n,                    // ~ 24h at 400ms slots
  feeStructure: FeeStructure.custom({
    token: USDC_MINT,
    perTxLamports: 10_000n,             // ~ 0.001 USDC equivalent
    revenueSplitBps: 5_000,              // 50% to operator
  }),
});

Roadmap

The SDK exposure of custom-fee configuration is tracked in ENG-6886. Three deliverables under that umbrella:

1. SDK + docs surface for what's already supported.

2. Custom-token fees (USDC + arbitrary SPL).

3. Revenue capture for grid operators.

See also

• Sessions — what a session is and what's bound to one.

• Settle-back guarantees — how state returns to L1 when a session closes.

• Migrate from L1 — what changes when you move an existing program to a session.