Registrai: data on the Arc ecosystem

Registrai publishes open data on Arc, Circle's blockchain: a directory of 297 projects with the evidence for each status (142 live on mainnet, 21 deployed, 134 announced), stablecoin payments to apps on Arc mainnet every hour, the Arc indices, and a public API and MCP server.

Directory last reviewed 2026-11-01. Data CC BY 4.0. Registrai is independent: not run or reviewed by Circle or Arc.

Arc

• Arc in numbers: USDC and EURC supply, stablecoins and TVL, estimated daily volume, active accounts and a dated timeline, each figure with its source
• Arc blockchain: facts with sources: mainnet date, gas token, EVM compatibility, validators, stablecoins, chain ID, RPC and explorer
• Arc developer reference: chain ID, public RPC endpoints with hourly uptime and latency, deploying contracts, accepting USDC, MCP and x402
• Arc vs Ethereum vs Solana for stablecoin payments: fees, block times and finality, measured
• How to get USDC onto Arc: on-ramps, exchanges and bridges, each with its evidence

Apps and projects on Arc

• Arc ecosystem directory: every project building on or announced for Arc, with its status and the evidence for it
• Apps on Arc: stablecoin payments and volume per app over the last 24 hours, hourly from Arc mainnet
• Most-used apps on Arc, last 7 days: apps ranked by stablecoin payments received
• Apps that accept USDC on Arc: payment apps live on Arc mainnet
• New on Arc, last 30 days: projects that went live and apps added to the index
• Apps built with Arc Studio: apps from Circle's AI coding agent that are public on GitHub, and which of them reached mainnet; weekly
• Arc indices: the Arc Builders, Integrations and Ecosystem indices, hourly

Reports

• AI answers about Arc: which pages AI models cite when they answer questions about Arc; weekly

Data access

• Arc blockchain data API and MCP server: public JSON API and read-only MCP server, no key
• llms.txt: index of every page for AI tools
• llms-full.txt: the whole reference in one file
• Open data on GitHub: the directory and figures as files, refreshed daily

Method

• Methodology: definitions of every figure and status, sources and limits
• How we publish: evidence, corrections and what nobody can pay for
• Corrections: every change to the directory, dated
• Verified builders: builders who verified their Arc contracts on the registry