Cronos launchpad listen tool: catch the pool open

Cronos App CEO Ryan Wyatt frames the tape as Sep 14 product roadmap · Sep 15 launchpad info · Sep 17 app launch—this post converges on launchpad / token / pool deploy + first liquidity: Factory PairCreated arrives → layer Transfer / Mint → first-liquidity card. Brew BNB same-cap twins watches twin verify; here we watch the Cronos launchpad pool heartbeat.

Run on the public endpoint · blockreq.com register for 3M free requests monthly.

Use	Endpoint
Public HTTPS	https://cronos-rpc.blockreq.com/v1/rpc/public
Public WSS	wss://cronos-rpc.blockreq.com/v1/rpc/public
Private	Trailing public → {API_KEY} (keys stay local)

Chain: Cronos EVM chainId = 0x19 (25). Public endpoints · eth_subscribe · Plans · Register.

1. Hook: launchpad × catch the pool open

Tape feel	On-chain signal	Watch
Launchpad pool open	Factory PairCreated	token0 · token1 · pair
Token land	same-window Transfer / deploy cluster	CA candidates · launchId
First liquidity	pair Mint / Sync · LP Transfer	amount0 · amount1
Sniper tape	first liquidity → outbound	Dedupe = pair + firstMintTx

When the official announcement posts the Factory / launchpad address, paste it into the UI fields and run; the PairCreated + Transfer listen pattern is live on Cronos public WSS today.

2. Event: PairCreated → Transfer / Mint first liquidity

Keep local JSON LAUNCHPAD_FACTORY (editable) + optional QUOTE_HINT (WCRO / USDC, …). One Cronos public WSS: subscribe Factory PairCreated, decode the pair, then narrow-listen Mint / Transfer on that pair.

Step A · Subscribe Factory PairCreated

{
  "jsonrpc": "2.0", "id": 1, "method": "eth_subscribe",
  "params": ["logs", {
    "address": "LAUNCHPAD_FACTORY",
    "topics": ["0x0d3648bd0f6ba80134a33ba9275ac585d9d315f0ad8355cddefde31afa28d0e9"]
  }]
}

• topics[0]: V2-style PairCreated(address,address,address,uint256) (confirm against Factory ABI; swap in an equivalent pool-create topic when needed).
• Decode token0 / token1 / pair → write launchState[pair], open the first-liquidity window.

Step B · Narrow-listen pair: Mint + Transfer

{
  "jsonrpc": "2.0", "id": 2, "method": "eth_subscribe",
  "params": ["logs", {
    "address": "PAIR_ADDRESS",
    "topics": [
      ["0x4c209b5fc8ad50758f13e2e1088ba56a560dff690a1c6fef26394f4c03821c4f",
       "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]
    ]
  }]
}

Field	Rule
firstMint	first Mint(address,uint256,uint256) on that pair
lpHint	same-window LP Transfer size / Sync reserve skim
quoteSide	token0/1 hits QUOTE_HINT
ready	PairCreated + firstMint both seen

Step C · Pool-open card fields

{ chain: "cronos", pad: "app-launchpad", factory, pair, token0, token1, amount0, amount1, firstMintTx, blockNumber, ts }

Dedupe on pair + firstMintTx; demo knobs: LAUNCHPAD_FACTORY and quote hints.

3. Browser demo (StackBlitz)

Default Cronos public WSS; paste Factory / launchpad address + quote hints, hit Start, stream pool-open cards. Code lives in StackBlitz — the post only embeds the preview:

Repo: blockreq/blog-demos → examples/cronos-app-launchpad-listen (Vite+React+viem; open repo root in StackBlitz).

Product page: ZH · EN

WSS  → wss://cronos-rpc.blockreq.com/v1/rpc/public
HTTPS→ https://cronos-rpc.blockreq.com/v1/rpc/public
env  → LAUNCHPAD_FACTORY · PAIR_CREATED_TOPIC0 · QUOTE_HINT · MINT_TOPIC0

Keyed: swap trailing public for {API_KEY}. Quota: blockreq.com register for 3M free requests monthly.

4. Alert rhythm

1. PairCreated arrives → decode token0 / token1 / pair · open first-liquidity window.
2. Mint / Transfer check → firstMint lands · quote side tagged when present.
3. Outbound → Cronos launchpad · pair=… · t0=… · t1=… · mint=… · blk=….
4. Dedupe → one push per pair + firstMintTx.

On disconnect: reconnect and re-subscribe; gap-fill with HTTPS eth_getLogs on the same Factory. POST → https://cronos-rpc.blockreq.com/v1/rpc/public.

5. Summary + CTA

1. Grain: Cronos launchpad watch = PairCreated + first liquidity.
2. Recipe: Factory + PairCreated topic + pair Mint/Transfer → pool-open card.
3. Runnable: browser on BlockReq Cronos public WSS; demos1 paths above.
4. Start: Public endpoints + blockreq.com register for 3M free requests monthly.

Next: paste announced Factory into JSON → webhook → stack on-screen with Brew BNB twin pools open cards. Docs · Pricing · Register.