Build on Fling: API, SDK, MCP

Fling is API-first. If you can do it in the UI — create, trade, attach referrers, watch graduation — you can do it through REST, TypeScript or Python SDKs, MCP, or webhooks. Day-one chain: Robinhood Chain (EVM). Portable to deployments with canonical Uniswap v4.

One base URL: http://localhost:3010/v1

Pre-launch. Contracts tested; public mainnet and fling.fun are not live yet. No external firm audit — the internal review is published in full at /security.

Security model

Fling does not claim to be audited for mainnet readiness in this UI. Every finding from the internal review — what it was, and what it would have done — is published at /security, and the full model, including trusted-party powers and known limits, is in the repo at docs/SECURITY.md. Read one of them before you integrate or trade size.

Non-custodial: the site never holds keys or funds; you sign every create, trade, and claim.
Supply is fixed; graduated liquidity has no withdraw path in the locker.
Owner powers (fee rates, quote enablement, creator-stream override) are real — they are documented, not hidden.
Tokens have no intrinsic value. Prices can go to zero. Nothing here is financial advice.

Prefer honesty over marketing: we do not use "guaranteed", "risk-free", or "audited" claims on this front end. External audit status belongs in the checklist and SECURITY doc when it exists — not in banners.

Reference & discovery

OpenAPI reference ↗
Every REST endpoint with schemas. Import into Postman or generate a client.
llms.txt ↗
Plain-text summary of the platform for language models.
skill.md ↗
Agent skill: how to launch, quote, trade and claim through the API.
MCP server ↗
Model Context Protocol manifest; the server lives in packages/mcp.

WebSocket: ws://localhost:3010/v1/ws — channels tokens.new, tokens.graduated, koth, trades, trades.account. One connection, multiplexed; replay gaps with GET /trades?sinceSeq=.

SDKs

@fling/sdk (TypeScript)
Typed REST + WS client and viem helpers: prepareBuy, executeBuy, prepareCreate… Source in packages/sdk.
fling (Python)
Minimal REST client plus web3 transaction building. Source in packages/sdk-python.
MCP server
Exposes the SDK as tools so Claude, Cursor and other agents can launch and trade. Source in packages/mcp.

For bots and terminals

You never need our servers to trade: the contracts are permissionless. Use the API for quotes and unsigned transactions, or call the router directly. Pass your own address as referrer on every trade and you earn 7% of the 1% fee (700 bps of the fee) on the volume you route. Apps that originate launches earn 3% of that token's fees for life via createReferrer.

Chain: Anvil (31337)
Launch fee: 0.0005 ETH
Trade fee: 1.00% of the quote leg
Fee split (creator / protocol / trade ref / create ref): 6000 / 3000 / 700 / 300 bps of fee
Sniper tax: 98% → 0% over 6s after launch and graduation
Wallet cap: 2% of supply for 2s after launch
Curve: 793.1M sold on curve, 206.9M to pool, raise 4 ETH (WETH preset)

FlingRouter: 0x2279B7A0a67DB372996a5FaB50D91eAA73d2eBe6
Launchpad: 0xa513E6E4b8f2a923D98304ec87F64353C4D5C853
FeeVault: 0xDc64a140Aa3E981100a9becA4E685f962f0cF6C9
FlingHook: 0xa77eCcF122d0Ba783D3629B8433c9e9227e820cC
Locker: 0x0165878A594ca255338adfa4d48449f69242Eb8F
PoolManager: 0x5FbDB2315678afecb367f032d93F642f64180aa3
WETH: 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512
USDG: 0x9fE46736679d2D9a65F0992F2272dE9f3c7fa6e0

Rate limits: unauthenticated reads are limited per IP; sign in with SIWE (POST /auth/siwe/nonce → /verify) for an API key with higher limits and webhook access. Every POST honours an Idempotency-Key header.