Grant Application - CoW Protocol Playground Block Explorer Integration

RFP Response: CoW Protocol Playground Block Explorer & Transaction Analysis

Author(s) CoBuilders Team GitHub: CoBuilders · GitHub Website: cobuilders.xyz

Experiences and Qualifications CoBuilders is a blockchain-native R&D and engineering studio focused on developer tooling, smart contracts, protocol, and L2 development, and DeFi/Dapp engineering. We take a research-driven, security-minded approach to building reliable systems across the Web3 stack. We’ve partnered with leading organizations such as Arbitrum, OpenZeppelin, Tools for Humanity, ZetaChain, SeedGov, and others across the ecosystem.

Grant Category Developer Tooling / Infrastructure

This grant responds to the CoW Grants Program RFP for integrated block exploration and transaction analysis tools for the CoW Protocol Playground.

Grant Description The CoW Protocol Playground currently lacks local tools for transaction inspection and debugging. Developers must rely on external services like Etherscan, which don’t work with local/forked chains.

Our Solution: Integrate Otterscan (a mature, open-source block explorer designed for local development chains) with the CoW Protocol Playground. Otterscan has native Anvil support and is actively maintained with 2.5k+ GitHub stars.

Current Status: We have a working PoC with Otterscan running, connected to the local Anvil chain with basic Docker integration.

This grant will complete the integration by: -Otterscan Integration: Production-ready Docker Compose setup with contract verification support (local or default Sourcify) -Frontend Integration: Modify CoW Swap and CoW Explorer frontends to replace Etherscan URLs with local explorer URLs (http://localhost:8003) -Documentation: Complete user and developer guides

What Otterscan Provides (Built-in):

• Block and transaction browsing
• Transaction traces and call graphs
• Gas profiling and analysis
• Contract code viewing (when verified)
• Address transaction history
• Search functionality
• Failed transaction debugging with revert reasons

What We’ll Build:

• Production-ready Otterscan Docker Compose integration
• Contract verification setup (local or default Sourcify)
• Frontend URL modifications in CoW Swap and CoW Explorer
• Configuration for seamless development experience
• Documentation

Demo Screenshots: In the URL below, are example views from our working Otterscan integration, demonstrating how developers will be able to inspect CoW Protocol transactions locally with full traces, logs, and decoded call data.

Figure 1 — Transaction Overview Provides a high-level summary of the transaction: gas usage, calldata decoding, token flows, involved contracts, revert reasons (if any), and metadata.

Figure 2 — Transaction Logs View Displays decoded event logs emitted during the settlement flow, including WETH transfers, CoW settlement events, Uniswap swaps, and USDT movements.

Figure 3 — Transaction Trace View Shows the full call graph for a CoW Protocol settlement, including internal calls, token transfers, Uniswap interactions, and fallback executions.

Type of Grant Milestone-based Grant

This is a milestone-based grant with clear deliverables at each stage, enabling verification of progress and quality before proceeding to subsequent phases.

Milestones

Milestone	Title	Due Date	Funding Request
M1	Otterscan Integration	Week 1	40% ($3,000)
M2	Frontend Integration	Week 2	40% ($3,000)
M3	Documentation	Week 2-3	20% ($1,500)

Milestone 1: Otterscan Integration (40% - $3,000) Deliverables:

• Seamless Otterscan integration into existing Docker Compose (fork and non-interactive modes)
• Production-ready configuration with optimized settings for Anvil
• Configure service networking and dependencies.
• Ensure all Otterscan features work correctly (traces, gas profiling, contract viewing)
• Contract verification setup:
  • Configure Otterscan to support contract verification
  • Option to use local Sourcify service OR default Sourcify endpoints
  • Test verification works with both approaches
• Documentation of configuration options and trade-offs

Success Criteria: Otterscan is fully functional with all debugging features available, and contract verification is working.

Milestone 2: Frontend Integration (40% - $3,000) Deliverables:

• Modify CoW Swap frontend to replace Etherscan links with local explorer URLs (localhost:8003)
  • Update transaction hash links
  • Update address links
  • Add environment variable configuration for the explorer URL
• Modify CoW Explorer frontend to add “View on Blockchain” links pointing to local Otterscan
• Implement dynamic URL generation based on deployment mode (local vs production)
• Test all navigation flows work correctly

Note: This requires code changes in the CoW Swap and CoW Explorer repositories to replace production URLs with configurable local explorer URLs.

Success Criteria: One-click navigation from frontends to the local block explorer for all transactions and addresses

Milestone 3: Documentation (20% - $1,500) Deliverables:

• Complete user guide for using Otterscan with CoW Protocol
• Developer documentation for maintaining and extending the setup
• Troubleshooting guide
• RFP compliance document showing all requirements met

Success Criteria: Documentation enables new developers to use and maintain the explorer without assistance

Duration Commencement Date: Upon successful approval, we will set a kickoff date Completion Timeline: 2-3 weeks for core deliverables

Funding Request Total: $7,500 USD

Payment split: $5,000 in xDAI + $2,500 in COW

Breakdown by Milestone: M1 (Otterscan Integration): $3,000 (40%) M2 (Frontend Integration): $3,000 (40%) M3 (Documentation): $1,500 (20%)

**Justification: **As mentioned above, this 2-3 week project delivers all RFP requirements by integrating proven open-source tools (Otterscan + Sourcify). The work includes Docker configuration, frontend modifications to replace Etherscan URLs, and comprehensive documentation.

Gnosis Chain Address 0x483Ee74762461981f2828Ded35E901B9B2424A01

Terms and Conditions By submitting this grant application, we acknowledge and agree to be bound by the CoW DAO Participation Agreement and the CoW DAO Grant Agreement Terms