Launch a coin on Solana

Build, sign and submit a Payday launch from your app.

A terminal or bot can launch a Payday coin for its user. The API runs the same launcher as payday.direct, so the coin gets the same fee settings: the same Payday token burn, the same DEX reimbursement and the same payouts.

Payday builds the transactions. The user's wallet signs them and pays for the launch. Payday never holds the wallet's key.

Before you start

You need a launch key: sign in on API keys and make a key with Allow this key to launch coins switched on. Keep it on your server.

1. Create the launch

curl -X POST https://payday.direct/api/v1/launches -H "Authorization: Bearer pd_YOUR_KEY" -H "Content-Type: application/json" -d '{
  "wallet": "THE_LAUNCHING_WALLET_ADDRESS",
  "name": "Example Coin",
  "symbol": "Example",
  "description": "What the coin is about.",
  "image": "BASE64_PNG_JPEG_GIF_OR_WEBP",
  "dev_buy_sol": 0.5,
  "fees_to": "examplehandle"
}'

The answer has the new coin's mint, a launch id and the transactions to sign. Nothing is on chain yet. Every field.

2. Sign, without sending

Have the wallet sign every transaction within about 60 seconds. Each is a base64 Solana versioned transaction; the launch one already carries the coin's own signature, so the wallet adds its signature and leaves the message as it is. A wallet's "sign all transactions" does exactly this.

import { VersionedTransaction } from "@solana/web3.js";
const txs = launch.transactions.map((t) => VersionedTransaction.deserialize(Buffer.from(t.transaction, "base64")));
const signed = await wallet.signAllTransactions(txs);   // Phantom, Solflare, or your own signer
const out = {}; const split = [];
launch.transactions.forEach((t, i) => {
  const b64 = Buffer.from(signed[i].serialize()).toString("base64");
  if (t.name.startsWith("split_")) split.push(b64); else out[t.name] = b64;
});
if (split.length) out.split = split;

3. Submit

curl -X POST https://payday.direct/api/v1/launches/LAUNCH_ID/submit -H "Authorization: Bearer pd_YOUR_KEY" -H "Content-Type: application/json" \
  -d '{ "signed": { "launch": "BASE64", "buy": "BASE64", "split": ["BASE64"] } }'

The answer has status: "launched", the mint, the launch signature and the coin's links.

When the network is slow

504 unconfirmed means the launch was sent and is not confirmed yet. Never create it again. Submit the same launch again, or read GET /launches/{id}, which stays submitting until it turns launched or expired. not_landed means the network ruled it out and no coin was made: create a new launch.

The fee split

The split_ transactions lock the coin's fees to the account in fees_to in the same signing round. If fee_split.status comes back pending, the coin stays hidden on Payday until it is locked: ask for fresh transactions with POST /launches/{id}/split, have the wallet sign and send these itself, then report their signatures to POST /launches/{id}/split/confirm.

Rules

• The launching wallet pays the network fees and its first buy. The DEX reimbursement goes to the wallet that signed the launch.
• Launches made with your key are recorded under the X account that owns the key.
• 8 launches per wallet and 30 per key every 10 minutes, 500 per key a day.
• An account that opted out of Payday cannot be named in fees_to.