TariffShield

Programmable customs-bond collateral. US importers post yield-bearing USDC instead of dead-weight cash collateral; a Soroban smart contract auto-tops-up the bond during tariff spikes; the surety partner keeps emergency clawback authority.

A working end-to-end system on Stellar: one Soroban contract, a TypeScript SDK, a REST API, a web dashboard.

Contract address	CBLASRVG7NRAFP2CDPVSF4WTJBKC6L4FKT2XHR3OH7CLICUBPVQ4PBBF
Network	Stellar (Soroban RPC, testnet)
Collateral token	Native XLM SAC CDLZFC3SYJ…CYSC (stand-in for USDC; mainnet would use Circle USDC)
License	MIT

See PITCH.md for the market case, ARCHITECTURE.md for the technical deep-dive.

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What it does

A US importer of consumer electronics doing $40M COGS from Shenzhen / Vietnam / Bangladesh needs a continuous customs bond. CBP sizes the bond at ~10% of expected annual duty obligation. The importer's surety asks for 50–100% cash collateral against that bond — held in a non-interest-bearing escrow account at the surety, for an average 314 days. When tariffs spike (Section 301 hike, reciprocal regime, AD/CVD order), CBP places shipments on release hold until the bond is topped up. The importer either wires more cash (working capital hit) or watches freight pile up at port while D&D meters run.

TariffShield replaces that cash-with-surety arrangement with a Soroban escrow contract:

• The importer deposits USDC into a collateral bucket (what the bond requires) and a reserve bucket (auto-top-up pool)
• The platform acts as a tariff oracle — re-computing required_collateral from the importer's ACE Portal duty data
• When tariffs spike and required > collateral, anyone can call auto_top_up — the contract moves min(shortfall, reserve) from reserve to collateral atomically, no surety re-underwriting cycle
• Yield accrues to the importer via Franklin Templeton's BENJI tokenized T-bill (live integration on the roadmap)
• The surety retains a one-call emergency clawback authority on importer default — drains both buckets to the surety wallet and freezes the account

The system runs end-to-end on Stellar, so you can exercise the full flow without partnerships or licensing.

Why this matters (the short version)

• $3.6B in customs bond insufficiencies in FY2025 — double 2019 (CBP)
• 27,479 distinct insufficiency events
• Surety premiums up 200% since the April 2025 reciprocal-tariff regime
• ~150,000 US continuous bonds in force; ~$10B aggregate face value; ~$5–10B in importer cash sitting in non-interest-bearing surety escrow accounts daily
• At a 4–5% T-bill yield, that's $200–400M/year of forgone yield for importers — every year

Existing surety SaaS (Roanoke, Avalon, GreatAmerican) is PDF + email driven. Nobody has a digital collateral instrument. We don't replace the surety — we replace the collateral instrument they accept. Same clawback authority, same regulatory posture; new cash mechanic.

Pricing model: 0.25–0.5% AUM, recurring. A 100-importer pilot at $1.5M average TVL is ~$150M TVL → $750K ARR; 10,000 importers is $75M ARR.

Repo layout

tariffshield/
├── contracts/tariff-shield/        Rust Soroban contract (8 entrypoints, 14 tests, ~12KB wasm)
├── packages/sdk/                   TypeScript SDK wrapping the contract over Soroban RPC
├── apps/api/                       Express 5 + Postgres orchestrator + mock CBP CSV ingest
├── apps/web/                       Next.js 16 dashboard — importer + surety admin
├── scripts/sdk-smoke.ts            Read-only smoke check against the live contract
├── docker-compose.yml              Postgres on :5443
├── deployments.json                Contract ID + addresses + verification tx hashes
├── Cargo.toml                      Rust workspace
└── package.json                    npm workspaces

One git repo. npm workspaces resolves the TypeScript packages; cargo workspace resolves the Rust contract. docker compose up brings up Postgres.

Quickstart

# 1. One-time toolchain
rustup target add wasm32-unknown-unknown
# stellar CLI: https://developers.stellar.org/docs/tools/cli

# 2. Install
git clone <this repo> tariffshield && cd tariffshield
npm install
(cd contracts/tariff-shield && cargo build --target wasm32-unknown-unknown --release)

# 3. Local Postgres
docker compose up -d

# 4. Configure env
cp .env.example .env
cp .env apps/api/.env                # API reads from apps/api/.env
cp apps/web/.env.example apps/web/.env.local

# 5. Run
npm run dev:api      # API on :3002
npm run dev:web      # Web on :3000

Open http://localhost:3000.

The pre-deployed contract works out of the box — your .env.example already points at CBLASRVG7NRAFP2CDPVSF4WTJBKC6L4FKT2XHR3OH7CLICUBPVQ4PBBF. To deploy your own:

stellar keys generate --fund my-admin --network testnet
stellar contract deploy \
  --network testnet \
  --source-account my-admin \
  --wasm target/wasm32-unknown-unknown/release/tariff_shield.optimized.wasm
# then `stellar contract invoke <C…> -- initialize --admin <G…> --surety <G…> --token <SAC…>`

Replace TARIFF_SHIELD_CONTRACT_ID in your .env.

Verification flow

The full happy path runs end-to-end:

1. Signup as importer. POST /auth/signup — creates a user record.
2. Register importer. POST /importers — backend generates a Stellar keypair, funds it via friendbot, calls register_importer on-chain. Example tx b50f2090…f161f5.
3. Deposit 30 XLM collateral + 100 XLM reserve. Two contract calls. Example tx dbc981c6…87daa.
4. Upload tariff CSV. Platform recomputes required_collateral from annual_duty × 10% × 50%. Creates a shortfall scenario.
5. auto_top_up — moves the exact shortfall (50 XLM) from reserve to collateral atomically.
6. Accrue simulated yield (surety admin role).
7. clawback (surety admin, on default scenario) — drains 130 XLM to surety wallet + freezes the account. Example tx fb698e46…96ca19.

All seven steps run as real on-chain transactions. The full set of verification tx hashes lives in deployments.json.

Stack

Layer	Choice
Smart contract	Rust 1.94 + soroban-sdk 22 + stellar CLI 25.2
Contract tests	cargo test (14 unit tests, all pass)
SDK	TypeScript 5 + @stellar/stellar-sdk 15 (Soroban RPC)
API	Express 5 + Postgres 17 + bcryptjs + JWT + Zod + helmet + rate-limit + CORS
Web	Next.js 16 + Tailwind v4 (App Router, Turbopack)
Deploy	Render (API) + Vercel (web) + Neon (Postgres) + Stellar (contract)

What's intentionally out of scope

The current build pairs the on-chain contract with synthetic CBP data and a mock surety admin. The production gap is non-trivial; the roadmap in ARCHITECTURE.md lists 16 specific items, but the four real gates are:

1. Surety partnership. Production routing through a state-licensed surety requires a 6–12 month sales cycle with one of Roanoke / Avalon / GreatAmerican / Liberty Mutual. The system runs without it.
2. CBP ACE API access. Not publicly accessible — needs surety-side relay or per-importer OAuth. The system uses CSV upload for tariff-exposure ingestion.
3. Real BENJI integration. Franklin Templeton's tokenized T-bill is already on Stellar at $270M+ TVL but routing real fund flow requires a custody agreement. Today, yield accrual is recorded on-chain by the platform admin.
4. State-by-state insurance regulator approval. Sureties are regulated in every US state. Changing the collateral instrument backing a bond is an insurance question, not just a CBP question.

These gates are GTM, not technical. The technology, end-to-end, works today.

License

MIT. Contributions welcome — the roadmap section in ARCHITECTURE.md lists scoped tasks with effort labels.