FONE / Operated cross-chain bridge engineering
Build an asset bridge that feels like part of your product. Passage Bridge gives technical teams a connected starting point for route quotes, approvals, execution and transfer tracking—with direct access to the engineer behind it.
Tech stack
Solidity bridge contracts connect Ethereum Virtual Machine (EVM) transfer workflows with independent message approval, relayer execution and TypeScript backend services, supported by Foundry tests.
For ecosystem teams and experienced Web3 developers building and operating dedicated bridge routes.
Two networks. One operating view.
Source · Approval · Destination
FONE / SIGNATURE ENGINEERING
CROSS-CHAIN
THE DELIVERY BEHIND YOUR NEXT MOVE
Helping 3+ infrastructure teams build connected cross-chain asset-transfer workflows.
Infrastructure teams supported
Cross-chain asset infrastructureEngineering hours saved per client, on average
Independent approvals · relayers · cross-chain reconciliationArchitecture and delivery, directly with the builder
Your direct engineering partnerSource, validation and setup, assembled around your selected modules.
A DELIVERY SCENARIO
Protocol teams & cross-chain infrastructure builders
A technical team wants a branded bridge for selected EVM routes. Start with quotes, independent approval, execution and transfer tracking, then shape liquidity and operations for those routes.
Focus specialist engineering on the networks and operating model.
CLIENT FEEDBACK
“Working directly with the engineer made bridge development a completely different experience. Clear responsibilities for approvals, the relayer and transfer tracking let our team focus on making liquidity and the user experience on our target networks the best they could be.”
Choose the product modules, branding and integrations around your launch.
Walk through setup, the codebase and release checks directly with Fone.
Add ongoing maintenance and iteration support as your product grows.
THE BUSINESS FLOW
Review the route, fee and destination inventory.
An independent approver authorizes the transfer message.
The Relayer executes an approved destination payment.
Track messages, receipts, inventory and recovery tasks.
FROM FIRST CLICK TO BUSINESS OUTCOME
Explore the real product, one customer moment at a time. Screens show a demo workspace with sample data.
THE BUSINESS IN ACTION / 01
Give the user a clear completed-transfer outcome under your brand. Keep the destination and received amount easy to find.
THE BUSINESS IN ACTION / 02
Bring route, amount and fees into the quote. Let users review the journey before committing their assets.
THE BUSINESS IN ACTION / 03
Follow initiation, approval, execution and finality as distinct steps. Make waiting understandable instead of sending users looking for answers.
THE BUSINESS IN ACTION / 04
Bring completed and in-progress transfers into one history. Give returning users and support a shared starting point.
BUSINESS MODEL
Design route fees around destination liquidity, rebalancing, network execution and support. Give users a clear quote and the team a defined operating model.
Build a branded route for your ecosystem or an integration for a business partner. Scope the source, signing infrastructure and operating procedures around that use case.
Add networks and operational automation as your requirements grow. Evaluate each new route’s asset behavior, liquidity and execution needs before launch.
Start with source delivery and brand customization. Add maintenance when you need it, and shape your own customer pricing and operating model.
BUILT BY FONE / 0xF1
Work directly with Fone, the independent engineer behind this product. Discuss the business, review the code and shape the release with the same person.
Meet the builderTHE ENGINEERING BEHIND IT
The supplied two-chain walkthrough follows source initiation, independent approval and destination execution. Solidity and Foundry provide the contract development foundation.
SEE IT BEFORE YOU BUILD
Use these product screens as the start of a live walkthrough. Review source, business flows and verification records with the person who built them.
Walk through the productWHAT WE CAN ADAPT
Adapt branding, language, transfer entry points, recipient history and support flows to your product.
Assess named networks and assets, fees, liquidity budgets, approval responsibilities and monitoring.
Scope production signing, multisig operation, RPC infrastructure and external review separately, with target-network acceptance before release.
SEE THE PRODUCT IN ACTION
The refreshed DApp captures follow a transfer across the quote, approval, execution and final-confirmation stages. Open the timeline and history to see how the product communicates progress.
Walk through the product with Fone, then map the brand, modules and integrations your business needs.
Passage is an operated liquidity bridge. These captures use an isolated two-chain environment; the existing operations console is outside this capture set. The current signing runner is local-only. Production signing, liquidity operations, source licensing and network acceptance are implementation work.
Screens captured on 30 October 2026. Source snapshots, reproduction steps and product verification records are available for the technical walkthrough.
Explore the decisions behind these workflows before planning your own integration.
WHAT YOU CAN RECEIVE
React DApp and Vue operations console modules for transfer tracking and role-based operational work.
Solidity contracts, Nest API, separate Indexer and Relayer services, MySQL / Redis and shared API / deployment definitions. Source licensing must be confirmed before handover.
Agree configuration, deployment and recovery instructions, role responsibilities, historical evidence and acceptance criteria for the selected environment.
Choose the modules for your first release. We’ll put source access, licenses, setup, handover and optional support into one clear proposal.
Technical teams with signing and liquidity operations. Build an asset-transfer service for your multichain product. Reuse the transfer interface, independent approvals and operations workflow while defining your networks and liquidity model.
Cross-chain service fees and operating costs. See revenue options, costs and current scope.
No. It relies on independent message approval and destination liquidity. Approver responsibilities, signer control and operating procedures are part of the service design.
No. The current signing runner is restricted to the local environment. Production execution, key management, network behavior and external security review need a separately agreed implementation and acceptance scope.
The historical local routes model Ethereum, Optimism and Base with ETH, WETH and a standard ERC-20. New networks, token behavior and real external bridge services require individual integration and validation.
Yes. Build your branded version around the agreed modules: React bridge DApp and Vue operator source; Solidity bridge contracts and shared interfaces; NestJS API, independent Indexer and Relayer. The proposal specifies repository access, commercial-use licensing, setup documentation, available tests and deployment materials, plus the handover with Fone. Third-party components retain their own licenses; exclusive IP transfer, if needed, is agreed separately.
Start with your source and destination networks, asset routes, approval roles, signing and liquidity operations. Fone maps the reusable modules and integrations into a first-release plan with milestones, workflow tests and deployment checks. The launch date follows that scope and any separately arranged security review. Budget for relayer hosting, RPC, monitoring and transaction fees; destination liquidity needs its own operating budget. Maintenance and further development are optional, with their scope and price agreed separately.
Passage Bridge / FONE
Share your networks, assets and operational setup. Work directly with Fone on the bridge architecture, approval model and deployment path.
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