CryptoFeeScope (Snapshot Demo)

CryptoFeeScope Phase 1 is a snapshot-based fee viewer powered by the CoinGecko Demo API. The frontend reads a static fee_snapshot_demo.json file (USD / JPY) and shows one standard fee per chain.

What this demo includes (Phase 1)

• Snapshot-only rendering: the browser pulls /data/fee_snapshot_demo.json on load and every 60 seconds (no tiers, no 24h change column).
• Supported chains (standard fee only): Bitcoin (BTC), Ethereum (ETH), BNB Smart Chain (BNB), Solana (SOL), Tron (TRX), Avalanche C-Chain (AVAX), XRP Ledger (XRP), Arbitrum One (ARB), Optimism (OP).
• Mobile-friendly table layout that fits 360px width without horizontal scrolling.

Prerequisites

• Node.js 18 or later (for built-in fetch).
• CoinGecko Demo API key exported as COINGECKO_API_KEY (set export COINGECKO_API_KEY="<your_demo_key>").

Generate the demo snapshot

Use the helper script to fetch CoinGecko Demo prices (/api/v3/simple/price) and emit the snapshot:

node scripts/generate_fee_snapshot_demo.js > data/fee_snapshot_demo.json

Deploy the updated data/fee_snapshot_demo.json to Cloudflare Pages (or another static host). The frontend will automatically reload the file every 60 seconds and refresh the table.

Automatic refresh cadence

• The fee snapshot is generated from the CoinGecko Demo API by the Node script above. For local development you can continue to run it manually:

  node scripts/generate_fee_snapshot_demo.js > data/fee_snapshot_demo.json

• In production (Cloudflare Pages main branch), GitHub Actions runs the same script every 10 minutes via .github/workflows/update-fee-snapshot.yml, commits the refreshed fee_snapshot_demo.json when it changes, and pushes to main. Because the frontend polls fee_snapshot_demo.json every 60 seconds, users see updates with at most roughly 10 minutes (+ the 60 second polling interval) of lag.

• This is the Phase 1 arrangement. Later phases will migrate the data source to Cloudflare Workers / a shared API, replacing the scheduled snapshot commits.