🧊 Iceberg

Private accumulation and exit on Starknet. Iceberg runs scheduled DCA and TWAP orders. The chain records only that the STRK20 pool made a swap. It never records who was accumulating, how much they hold, or what their schedule is.

Built for the STRK20 Private Sprint, 14 to 31 August 2026.

The idea

Traders buy and sell large positions gradually instead of all at once. On a public chain, that strategy is visible to everyone. Your schedule, your running total, and your identity are all on display, so anyone can copy you or trade ahead of you.

Iceberg groups many users' scheduled orders into one anonymous pool swap per interval. Each person's chunk size, schedule, and total stay hidden inside that group. The chain shows only the combined swap. That swap is the tip of the iceberg.

1. Deposit into the STRK20 shielded pool. Then tell Iceberg privately to buy a token in N chunks.
2. Each interval, a keeper sums the chunks due from every active plan. It executes one swap for the whole group.
3. Claim your share back into the shielded pool whenever you want. You claim with a secret that only you hold.

What is actually private

Public	Private
Each interval's combined swap amount and its timing	Who created any plan
Net flow in and out of the pool	Per-user totals and schedules, mixed across the group
That a swap happened	Who claims

STRK20 always shows swap amounts and timing. Private DeFi routes through shared anonymizer contracts into public venues. So Iceberg claims identity privacy plus mixing. It does not claim amount privacy.

Read SPEC.md for the full design and the known tradeoffs.

Repo layout

• contracts/ holds the Cairo code. It contains the Iceberg core and the EkuboAdapter, with 20 unit tests and 1 mainnet-fork test. Read more.
• keeper/ holds the batch executor. It quotes AVNU for slippage protection and adds random timing jitter. It also deploys the local demo. Read more.
• ui/ holds the demo interface. It shows what the chain sees above a waterline, and what only you can decode below it. Read more.

Run it locally

The toolchain versions match the pins in StarkWare's starknet-privacy repo. You need scarb 2.17.0, starknet-foundry 0.59.0, universal-sierra-compiler, starknet-devnet 0.8.0-rc.3, and Node 24 or later.

Run the contract tests. One of them forks mainnet and swaps against real Ekubo liquidity.

cd contracts
snforge test        # 21 tests
scarb build         # required before you deploy: snforge builds test targets only

Run the full demo loop. This starts devnet, deploys the contracts, seeds two plans, runs the keeper, and serves the interface.

starknet-devnet --seed 0 --port 5050          # terminal 1

# terminal 2. Devnet freezes chain time between transactions, so advance it.
while true; do curl -s localhost:5050 -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"devnet_createBlock","params":{},"id":1}' >/dev/null; sleep 20; done

cd keeper && npm i && node deploy-devnet.mjs   # deploys everything and seeds 2 plans
npm start                                      # the keeper. See keeper/README.md for the env

cd ../ui && npm i && npm run dev               # set the RPC and contract address in Settings

The seeded plan secrets are demo-alice and demo-bob. Intervals last 60 seconds on devnet. Enter either secret in the lower half of the interface to decode that plan.

Status

The contracts, the keeper, and the interface all work against a local devnet. The test suite includes a fork test that swaps against real mainnet Ekubo liquidity.

The private create and claim flow is written against the StarkWare privacy SDK, but it is not live yet. StarkWare has not published the mainnet proving and discovery service URLs. The starter kit ships no Sepolia equivalents either. Until those exist, the deployed interface stays read-only.

License

MIT