Blockchain Stats Web App Development

I want a webapp (locally run initially), with a clear webUI, that displays the Chain, average block time (last 24h), blocks count and other averages can be added later (if it's easy to add it now, add it). Also some nice stats can be shown for increased emotional impact.

I want it to support as many chains as possible, even non EVM ones.

Something similar to this Dune board (but this one only shows for EVM chains)
Example: https://dune.com/jacobdcastro/avg-block-times

For Stacks we have:
https://api.hiro.so/extended/v2/blocks/average-times

Search and add for other known chains also, such as Bitcoin, Solana, Cardano, Near, Stacks (of course) etc, all new EVM chains (e.g. MegaETH, Monda etc) and to be able to extend it in the future.

Use publicly available fee APIs. If keys will be needed, I'll get some.

Let me start building the webapp. I'll create a structured project with a Node.js backend and a rich frontend dashboard.

Todos

Create project directory structure

Write blockchain-stats/package.json

Now the main backend server:

Write blockchain-stats/server.js

Now the frontend HTML:

Write blockchain-stats/public/index.html

Now the CSS:

Write blockchain-stats/public/style.css

Now the frontend JavaScript:

Write blockchain-stats/public/app.js

Now install dependencies and test:

Install npm dependencies

Check Node.js version for native fetch support

Good, Node 20 has native fetch. Let me do a quick syntax check and then test a few APIs to validate they work:

Check server.js for syntax errors

Start server and check status endpoint

You have made each blockchain into a cell, with the stats, that's ok and can exist as a "Cell view" but I also want a "Table View" and a way to search/filter by name/EVM/non-EVM/Bitcoin related (Bitcoin itself, Stacks, Babylon, etc).

Good additions. I'll:

1. Add a Table View alongside the existing Card/Cell view with a toggle
2. Add a search box (filter by name in real-time)
3. Add ecosystem filters: EVM / Non-EVM / Bitcoin (Bitcoin, Stacks, Babylon) / Cosmos
4. Add Babylon to the Bitcoin ecosystem group
5. Make the cosmos fetcher reusable for multiple Cosmos-based chains

Now let's verify the syntax:

Check JS syntax on both files

Get detailed syntax errors for both files

Test server.js loads without errors

Catch and display server.js load error

The port error confirms there's already an old server running — meaning the new server.js code loads and parses without errors. Let me do a clean syntax check:

Pure syntax check without executing server.js

Pure syntax check on app.js

Both files are clean. Let me also quickly verify the HTML is well-formed:

Verify key HTML element IDs exist

Find PID of process using port 3000

I killed that app just now, retry

Start server and check status endpoint

Server is up and already pre-fetching. Let me quickly validate a few chains came back with real data:

Sample chain data from live API

Parse and display chain results

35/42 working on first run. Let me fix the broken ones — bad RPC endpoints, NEAR params format, Polkadot, Algorand:

Diagnose NEAR, Algorand, and Stacks API responses

Get full block field lists and API responses

Check Stacks and NEAR API responses directly

Fetch Stacks and NEAR responses to files

Fetch Stacks average-times via Node

Test NEAR RPC with named params object

Test alternative public RPC endpoints

Test Fantom and Polkadot alternatives

Test Fantom blastapi, Polkadot subscan, Monad testnet

Test Fantom, Polkadot OnFinality, MegaETH, NEAR archival

Test Polkadot Substrate RPC endpoints

Test Polkadot timestamp via Substrate state storage

Now I have all the info to fix everything. Let me apply all fixes:

Edit server.js

Now fix the NEAR fetcher (params format) and Stacks response parsing:

Edit server.js

Fix Algorand (ts not timestamp) and Polkadot (full rewrite to Substrate RPC):

Edit server.js

Also fix the Algorand lastBlockAge to use the corrected latestTs:

Edit server.js

Now restart the server and verify:

Restart server with fixes

The old server is still running. Let me kill it properly:

Kill all node processes and restart server

Fetch and display all chain results after warmup

39/41 working. Let me fix the last two timeouts:

Test Cardano and Sei alternative endpoints

Test Cardano Koios with timing

Cardano Koios main endpoint is slow; guild endpoint works at 10s. Sei works on sei.drpc.org. Let me fix both:

Edit server.js

Now restart server with all fixes applied

Wait for warmup then check chain results

Test Sei EVM RPC alternatives

The direct test shows Sei responds in ~328ms — the earlier timeout was likely a fluke under server load. Let me restart and do a final check:

Final server test with all fixes

Check if server is running

Start server fresh

Wait for all chains to fetch then display results

Fetch chains and display final results

41/41 chains working. The dashboard is live at http://localhost:3000.

Todos

Here's a summary of everything that was built and fixed:

What's done — http://localhost:3000

Views

1. Cards view — the original grid, one card per chain with block-time gauge bar
2. Table view — sortable table with all chains in rows (click any column header to sort)

Filters

Chains (41/41 live)

1. Bitcoin ecosystem: Bitcoin, Stacks, Babylon (new)
2. EVM L1s: Ethereum, BNB, Avalanche, Fantom, Celo, Gnosis, Cronos, Moonbeam, Harmony, Aurora, Sei
3. EVM L2s: Polygon, Arbitrum, Optimism, Base, zkSync, Linea, Scroll, Mantle, Blast, Metis, Polygon zkEVM, Manta, Mode, Fraxtal
4. Testnet: Monad
5. Non-EVM: Solana, Cardano, NEAR, Algorand, Tezos, Hedera, Polkadot, Stellar, XRP, Cosmos Hub, Aptos, Sui

To start next time

cd blockchain-stats && npm start