Base $LAPTOP liquidity detector: first Mint/Swap

BSCN tape frames the $LAPTOP open around first liquidity × sniper bursts × thin-LP rhythm—this post builds a detector tool: first liquidity land, Mint / Burn / Swap density, early wallet concentration, short-window sniper bursts, thin-LP exits — one panel of cards. Base launch-spike watches open-window spike counts; here we watch single-launch liquidity structure. Technical listen craft for on-chain signals.

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

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

Chain: Base Mainnet EVM chainId = 0x2105 (8453). Public endpoints · eth_subscribe · Plans · Register.

1. Hook: first-pool liquidity × four detector lanes

Tape feel	On-chain signal	Watch
First liquidity	pair/pool Mint · first Sync	amount0 · amount1 · firstMintTx
Print density	Swap cluster · first N blocks / M sec	swapCount · unique buyers
Early wallet conc.	same-window Transfer to Top-K	holder-share skim
Thin-LP exit	Burn / negative ModifyLiquidity	withdraw size · residual-depth hint

Paste the $LAPTOP token / pair / pool addresses into the UI fields and run; the same recipe reuses for later Base single-launch opens.

2. Event: Mint / Burn / Swap + early wallets

Keep local JSON TOKEN · PAIR_OR_POOL (editable) + SPIKE_WINDOW_SEC · SWAP_BURST · TOP_HOLDER_SHARE · BURN_MIN. One Base public WSS: narrow-listen Mint / Burn / Swap on that pair/pool, and count early buyers via Transfer.

Step A · Subscribe pair Mint + Burn + Swap

{
  "jsonrpc": "2.0", "id": 1, "method": "eth_subscribe",
  "params": ["logs", {
    "address": "PAIR_OR_POOL",
    "topics": [[
      "0x4c209b5fc8ad50758f13e2e1088ba56a560dff690a1c6fef26394f4c03821c4f",
      "0xdccd412f0b1252819cb1fd330b93224ca42612892bb3f4f789976e6d81936496",
      "0xd78ad95fa46c994b6551d0da85fc275fe613ce37657fb8d5e3d130840159d822"
    ]]
  }]
}

• Mint topic · Burn topic · V2 Swap topic (swap in V3/V4 Swap topic0 when the pool ABI differs).
• First Mint → firstLiquidity card; short-window Swap count ≥ SWAP_BURST → sniper-burst card; Burn size ≥ BURN_MIN → thin-LP exit card.

Step B · Subscribe token Transfer (early wallet concentration)

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

Field	Rule
earlyBuyers	unique Transfer to set inside the first window
topShare	Top-K receiver share skim
burstReady	swapCount ≥ SWAP_BURST and uniqueBuyers clears the bar
thinExit	Burn / LP withdraw clears BURN_MIN

Step C · Detector card fields

{ chain: "base", pad: "laptop-liq", kind: "firstMint|swapBurst|holderConc|thinExit", token, pairOrPool, amount0, amount1, swapCount, uniqueBuyers, topShare, burnAmt, txHash, blockNumber, ts }

Dedupe on txHash + logIndex / same-window kind merge; demo knobs: addresses and thresholds.

3. Browser demo (StackBlitz)

Default Base public WSS; paste token / pair / pool + window and thresholds, hit Start, stream detector cards. Code lives in StackBlitz — the post only embeds the preview:

Repo: blockreq/blog-demos → examples/base-laptop-sniper-liquidity-listen (Vite+React+viem; open repo root in StackBlitz).

Product page: ZH · EN

WSS  → wss://base-rpc.blockreq.com/v1/rpc/public
HTTPS→ https://base-rpc.blockreq.com/v1/rpc/public
env  → TOKEN · PAIR_OR_POOL · SPIKE_WINDOW_SEC · SWAP_BURST · TOP_HOLDER_SHARE · BURN_MIN

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

4. Alert rhythm

1. Mint arrives → record firstLiquidity · open density window.
2. Swap / Transfer accumulate → swapBurst · holderConc threshold cards.
3. Burn arrives → thinExit card · residual-depth hint layered.
4. Dedupe → merge same-window same kind; per-log use txHash + logIndex.

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

5. Summary + CTA

1. Grain: Base single-launch detector = first liquidity + Swap burst + early wallets + thin-LP exit.
2. Recipe: pair Mint/Burn/Swap + token Transfer + window thresholds → detector card.
3. Runnable: browser on BlockReq Base public WSS; demos1 paths above.
4. Start: Public endpoints + blockreq.com register for 3M free requests monthly.

Next: pin token/pair JSON → webhook → stack on-screen with Base launch-spike spike cards. Docs · Pricing · Register.