Blockchain & Web3 Development Company in Seattle

Budget tracks the build, and the build is usually one of three: a scoped Web3 proof of concept at Seattle rates, a production smart contract suite (DeFi protocol, tokenization platform, NFT marketplace, supply chain ledger), or full production Web3 platforms with custody integration, account abstraction wallets, fiat on-ramps, and indexer infrastructure. Scope drivers include smart contract design, a hosted dApp demo, and a forked mainnet rehearsal. Seattle rates sit above Phoenix and Salt Lake City because of the AWS, Microsoft, and Coinbase Cloud talent premium. We give fixed-fee proposals rather than open T and M estimates.

Possibly. Washington State Department of Financial Institutions (DFI) enforces RCW 19.230, and in 2017 Washington was one of the first US states to actively examine crypto businesses for money transmitter compliance. Activities that typically trigger licensure include custodial wallets that hold customer funds, fiat-to-crypto on-ramps and off-ramps, hosted exchange functionality, and stablecoin issuance or redemption. Activities that typically do not include pure non-custodial smart contract development, software-only wallet code shipped without custody, and DAO tooling that never touches customer fiat. Washington has also adopted the Uniform Money Transmission Modernization Act, which clarified virtual currency scope. Our discovery phase produces a WA DFI applicability memo and a federal FinCEN MSB analysis, then refers regulated activities to specialist counsel (we are not lawyers, and Washington examiners are unusually thorough).

Yes. ION is a permissionless layer 2 network for Decentralized Identifiers (DIDs) anchored to Bitcoin, contributed by Microsoft to the Decentralized Identity Foundation. We integrate ION DIDs and W3C Verifiable Credentials for reusable KYC, employment claims, healthcare licensure, and supply chain attestations. Our work uses the official ION SDK, Sidetree protocol implementations, and Azure Active Directory Verifiable Credentials where clients are already on the Microsoft identity stack. ION works well when you need a decentralized identifier that is not controlled by any single issuer, but it is not a substitute for OAuth or OIDC for routine login flows. We will tell you when ION is the right answer and when it is overkill for the use case in front of you.

Every Web3 project we ship integrates OFAC SDN list screening at the wallet address level before any value transfer settles. We use Chainalysis Address Screening, TRM Labs, or Elliptic depending on client preference and budget, with Coinbase's open Tornado Cash address list as a baseline reference. Sanctioned address detection triggers a soft block in the dApp UI and a hard block at the smart contract layer for higher-risk flows. Our compliance memo includes the screening provider, the update cadence, the address-list-update SLA, and the incident response steps when a sanctioned address interacts with the protocol. This matters specifically because Treasury's 2022 Tornado Cash designation set a precedent that smart contract authors and front-end operators must treat seriously, and Seattle's federal court exposure to OFAC matters is significant.

Both, and the choice depends on transaction economics and counterparty risk tolerance. Ethereum mainnet remains the default for high-value institutional flows, governance tokens, and long-lived treasury contracts where finality and decentralization are non-negotiable. Coinbase Base, an Optimism Bedrock based L2 from Coinbase, makes sense when fee compression matters (most consumer dApps), when Coinbase's onboarding flow and Smart Wallet are useful, or when a Seattle-based founder wants engineering and listing proximity to Coinbase's Web3 product team. We deploy the same audited contract code to both layers when possible, use the canonical bridge for asset movement, and warn clients about L2 sequencer downtime risk and the seven-day optimistic withdrawal window. Arbitrum and Optimism mainnet remain solid alternatives when Base is not the right fit.

Every contract receives a layered review. First, static analysis with Slither and Mythril on every commit, in CI, with a zero-tolerance gate for high-severity findings. Second, fuzz testing with Echidna and Foundry invariants targeting protocol-specific properties (no value created from nothing, monotonic supply where required, role-based access invariants). Third, an internal code review against the OWASP Smart Contract Top 10 and Trail of Bits guidance. Fourth, a forked mainnet rehearsal at the actual block height the contract will deploy against, with all upstream protocol integrations live. Only then does the contract go to a third-party audit (Trail of Bits, ConsenSys Diligence, OpenZeppelin, Spearbit, Code4rena), and we facilitate fix-and-reaudit loops. Post-deployment, monitoring runs on Forta, Tenderly Alerts, and OpenZeppelin Defender, with a multisig pause guardian using Safe and hardware wallet signers.

Yes. Permissioned blockchain for aerospace parts provenance, FAA-traceability-adjacent records, and tier-one supplier attestations typically belongs on Hyperledger Fabric or Besu rather than a public chain, because counterparty identity and selective disclosure matter more than public verifiability. We design channel topologies, chaincode in Go or TypeScript, MSP (Membership Service Provider) configurations, and verifiable credential issuance flows that align with GS1 EPCIS event vocabulary for supply chain interoperability. For higher-trust public anchors we periodically Merkle-root the Fabric ledger to Ethereum or Bitcoin, giving customers verifiability without exposing trade-sensitive line items. We have studied Boeing's public pilots and IBM Food Trust patterns in depth, and we will steer you away from a public-chain rollout when a permissioned design is actually correct.

The Washington My Health My Data Act (HB 1155), effective 2024, regulates consumer health data well beyond HIPAA, including data that HIPAA does not touch (mental health apps, period trackers, fitness wearables, biometric inferences). It requires opt-in consent for collection, separate opt-in for sharing, a consumer right to deletion, and a private right of action. For Web3 projects this matters because on-chain data is functionally permanent, so tokenized health consent receipts or decentralized health identifiers must be designed so that personally identifiable information lives off chain in a privacy-preserving vault, with only commitments or zero-knowledge proofs on chain. We design these patterns, document the consent flow, and produce a compliance memo your privacy counsel can review against HB 1155 obligations alongside HIPAA where it applies.