Senior Blockchain Engineer – Smart Contracts & Tokenization (Contract) / YRS EXP REQ

Senior Blockchain Systems Engineer — Smart Contracts, Settlement & Tokenization (Contract)Job Summary Accorria is building a trust layer for high-value transactions by generating verifiable “data packets” (facts + evidence hashes + audit trail) and enabling smart-contract based settlement with optional tokenization and fractional participation. We’re seeking a senior engineer to ship the blockchain + smart contract layer that powers: • tamper-evident transaction packets (hashes + audit trails; no raw PII on-chain) • escrow-style settlement workflows (finite-state machine / event validation) • agreement/receipt-style tokenization (ERC-3525 preferred) • walletless onboarding patterns (Account Abstraction / relayer-friendly UX) You’ll work closely with the founder and engineering team to integrate Solidity smart contracts with our backend stack (FastAPI + Google Cloud) and deliver a demo-ready, production-minded prototype with clear proof artifacts (hashes, event trails, verification outputs). What You’ll Build (Deliverables) • Verifiable Packet System (RD-108-style close packet for vehicles) Deterministic transaction schema → evidence hashing → append-only audit log → validation (PASS/FAIL + missing items) → packet output (PDF/JSON + hashes) → redacted export. • Escrow / Settlement Smart Contracts (Finite-State Machine) Event-driven workflow (create → intent → funded → inspection optional → final payment → ready-to-close → mint receipt) with strict ordering, validation, and double-execution prevention. • Proof Artifact (Digital Bill of Sale / Receipt) Minted only at “ready-to-close,” representing proof of transaction, not legal title itself. • Tokenization Model + Fractional Participation (Optional lane) Agreement-based token model (ERC-3525 preferred) with a demoable “buy $X worth” participation flow (stablecoin rail approach is up to you to propose). • Backend ↔ Chain Integration Event indexing strategy + APIs/hooks for create/update/verify/query history + signature verification. Responsibilities • Design and implement Solidity smart contracts for escrow-style settlement workflows, including: • event ordering + required prior events • signer authenticity + replay protection • double-mint / double-execution prevention • secure release/refund/dispute state handling • Implement the hash-first architecture: • keep sensitive documents off-chain • store only hashes/references on-chain • provide a clean verification trail (timeline + checksums) • Define and implement an agreement-based tokenization model (ERC-3525 preferred): • slot/jurisdiction structure • per-agreement value semantics tied to contract state • optional fractional participation path • Build contract integration layer with backend services (FastAPI + cloud): • event listeners/indexing strategy • APIs for submit events / verify / query history • signing flows that support “walletless” UX where appropriate • Maintain strong security posture: • access control, invariants, tests, audit-ready patterns • Write clean documentation + a short runbook (how to demo, verify, troubleshoot) Qualifications • 3–7+ years building blockchain + backend systems or equivalent shipped work • Strong proficiency in Solidity and EVM-compatible networks • Proven experience shipping state-machine / multi-step workflow contracts (escrow, settlement, ordering constraints) • Strong understanding of smart contract security: • reentrancy, access control, signature verification, replay prevention • Experience integrating on-chain systems with backend services using: • event listeners, indexers, or APIs • Strong engineering judgment around PII handling: • no raw PII on-chain; hashes/references only • Able to work independently in a fast-moving startup environment and deliver milestone-based outcomes Preferred Skills • Experience with ERC-3525 (or agreement/receipt-style token patterns) • Token standards familiarity (ERC-20/721/1155) and fractional participation concepts • Familiarity with Account Abstraction / relayers / gas abstraction (UX-first onboarding) • Experience building tamper-evident audit trails (deterministic JSON, hashing, redacted exports) • Experience with Ethers.js (or similar) for contract interaction • Prior experience owning contract architecture end-to-end (spec → build → test → ship) Compensation & Engagement • Contract (1099) • $50,000 – $150,000 per year (contract equivalent; depends on scope and hours) • ~15–25 hours per week • Remote • Milestone-based contract with an equity component; cash payout timing is milestone-dependent as we finalize our current raise. • Long-term engagement possible based on delivery Why Work With Accorria • Build foundational smart-contract infrastructure for a real high-value transaction platform • Work on verification + settlement primitives (not “token hype”) • Define an agreement-first token model that supports compliance-heavy markets • Fully remote, flexible schedule • High ownership and direct influence on core architecture Work Location Remote Pay: $50,000.00 - $150,000.00 per year Work Location: Remote Apply tot his job Apply To this Job