Smeltor API Docs

1How it works

Deterministic resolver with structured JSON input. Any LLM or application can call the API directly. You describe the user's intent — a structured action (swap, earn, perp_open, bridge, borrow, restake, limit_order) or a multi-step plan — and Smeltor returns ready-to-sign EVM calldata. The user's wallet executes. We never touch funds.

One endpoint, two transports. Call the REST API directly from any language, or run the MCP server from any LLM client (Claude Desktop, Cursor, Inspector, custom agent loop). Both wrap the same engine — fee params, slippage clamping, aggregator failover, gas estimation, simulation, EIP-7702 atomic batching live in one place.

2The action catalogue

Pass one of these as action on /api/public/workflow/resolve, or chain several together via steps[] for a multi-step plan. Amounts pipe between steps automatically.

3Capabilities table

Live coverage as of this deploy. The authoritative source is GET /api/public/system/coverage — poll it any time.

Strategy templates. The resolver recognises higher-level strategy phrases and expands them into multi-step plans: basis_trade (long Ondo tokenized stock + short matching Hyperliquid perp = delta-neutral funding-rate yield), stock_yield (tokenized stock collateral on Felix Protocol → borrow → earn — ROADMAP-gated), leveraged_staking, yield_stack, hedge_earn. Trigger phrases: "basis trade on SPY", "delta neutral TSLA", "hedge SPY", "earn yield on my SPYon".

4MCP server config

Streamable HTTP transport, no auth, hosted on Supabase Edge Functions. Drop this block into your MCP client config (Claude Desktop, Cursor, Inspector, custom LLM agent) and the Smeltor tools become available immediately. mcp-remote handles the streaming transport for clients that don't speak it natively.

{
  "mcpServers": {
    "smeltor": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://juaroposgdkfbvqvzvxf.supabase.co/functions/v1/smeltor-mcp"
      ]
    }
  }
}

Smoke-test the MCP endpoint directly:

curl -sX POST https://juaroposgdkfbvqvzvxf.supabase.co/functions/v1/smeltor-mcp \
  -H "Content-Type: application/json" \
  -H "Accept: text/event-stream, application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

5REST: /resolve (the primary endpoint)

One endpoint, any action. Pass a single action + params for structured callers (agents, wallets) or a steps[] array for multi-step plans. The same endpoint accepts a natural-language intent string for callers who want the resolver to parse first — most production integrations pass structured input directly.

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "action": "swap",
    "params": {
      "fromToken": "USDC",
      "toToken": "ETH",
      "amount": "10",
      "chain": "base"
    }
  }'

Multi-step plans pipe amounts automatically. The example below swaps USDC→ETH, bridges to Ethereum, then stakes via Lido — three protocols, one request, one composed response.

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "steps": [
      { "action": "swap",   "params": { "fromToken": "USDC", "toToken": "ETH", "amount": "100", "chain": "base" } },
      { "action": "bridge", "params": { "token": "ETH", "fromChain": "base", "toChain": "ethereum" } },
      { "action": "earn",   "params": { "token": "ETH", "chain": "ethereum", "protocol": "lido" } }
    ]
  }'

The response carries the composed plan + ready-to-sign calldata, plus an execution object describing EIP-7702 batch grouping so single-chain plans with multiple txs collapse to one signature on supporting wallets (Coinbase Smart Wallet, MetaMask with EIP-7702, Privy embedded wallets).

{
  "steps": [ /* one entry per action with transactions[], simulationPassed, quoteFreshness, mevRisk, estimatedGas */ ],
  "execution": {
    "atomic": true,
    "totalSignatures": 1,
    "method": "eip7702_batch",
    "batches": [{ "chainId": 8453, "calls": [ /* approve + swap as one batch */ ] }]
  },
  "summary": "3-step plan · 1 signature · ~$0.012 gas · highest net APY 4.74%",
  "nextActions": [ /* per-action suggestions agents can render as buttons */ ],
  "warnings": [],
  "reasoning": [ /* NL inference trail when the caller passed a natural-language intent */ ]
}

6Testnet mode

Pass testnet: true on any /resolve call. The endpoint returns the same shape as mainnet, with network: "testnet", real calldata, and zero risk to user funds. The intended use is integration testing — partners can exercise the full request/response surface before any mainnet address is touched.

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "testnet": true,
    "action": "swap",
    "params": { "fromToken": "USDC", "toToken": "ETH", "amount": "10", "chain": "base" }
  }'

What's real on testnet: swap, bridge, earn, and the simulated EIP-7702 batch — every action returns calldata against testnet routers / contracts when an equivalent testnet deployment exists. What's mocked: perps (Hyperliquid / dYdX testnet is not configured), restake (EigenLayer testnet surface is intentionally read-only), and any protocol that only runs on mainnet. Mocked actions return a simulated: true step with representative response shape so integration tests can assert against it.

7Partner fees

Pass partnerFee (decimal, max 5%) plus partnerAddress on /resolve. The resolver deducts the fee from the input amount BEFORE running gates, then prepends a USDC.transfer(partner, fee) call to the EIP-7702 batch — the partner is paid in the SAME on-chain tx as the user's workflow. Atomic. Verified live on Base (tx 0xaf934d17…): a 0.20 USDC swap with 3% fee paid the partner 6000 raw units of USDC in the same transaction as the swap.

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "partnerFee": 0.03,
    "partnerAddress": "0xYourPartnerWallet…",
    "action": "swap",
    "params": { "fromToken": "USDC", "toToken": "ETH", "amount": "10", "chain": "base" }
  }'

8Portfolio endpoint

Returns the wallet's on-chain holdings plus DeFi positions detected via the receipt-token registry, plus a typed list of factual opportunities (idle_asset, yield_upgrade, consolidation). Opportunities are informational — never "recommendations" — so the calling agent picks. Data is pulled from Zerion (primary) with a viem multicall fallback when Zerion lags.

curl -sX POST https://api.smeltor.com/api/public/portfolio \
  -H "Content-Type: application/json" \
  -d '{ "walletAddress": "0xYourWallet…" }'

{
  "tokens": [ /* { symbol, address, chain, balance, usdValue } */ ],
  "positions": [ /* { protocol, kind, asset, chain, balance, apy } */ ],
  "opportunities": [
    { "type": "idle_asset",    "asset": "USDC",  "chain": "base",  "info": "100 USDC idle on Base" },
    { "type": "yield_upgrade", "from": "aave",  "to": "moonwell",  "delta_apy": 0.81 },
    { "type": "consolidation", "asset": "USDC", "chains": ["base", "arbitrum"] }
  ]
}

9Advanced actions

All of these flow through /api/public/workflow/resolve with the matching action value.

Limit orders (1inch LOP v4)

Returns EIP-712 typed-data + orderHash. Gasless for the user — resolvers pay gas when the order fills. NL: "buy ETH at $2000", "sell ETH at $3000". Gates: PARAM_REQUIRED, INVALID_PRICE, expiry range [60s, 30d].

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "action": "limit_order",
    "params": {
      "fromToken": "USDC", "toToken": "ETH",
      "amount": "100", "limitPrice": "2000",
      "side": "buy", "expiry": 86400, "chain": "base"
    }
  }'

Borrow (Aave V3)

On-chain reads (getUserAccountData, getReserveConfigurationData, getReserveCaps), post-borrow Health Factor projection, classification taxonomy (ok / warn / danger / liquidatable / no_collateral / asset_disabled / frozen / cap_exceeded). Variable rate (interestRateMode=2).

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "action": "borrow",
    "params": {
      "token": "USDC", "amount": "100",
      "chain": "base", "protocol": "aave"
    }
  }'

Restake (EigenLayer)

Deposits stETH, cbETH, or rETH into the corresponding EigenLayer Strategy contract on Ethereum mainnet. Returns approval + deposit calldata. Operator delegation is a separate flow surfaced via nextActions[].

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "action": "restake",
    "params": {
      "token": "stETH", "amount": "1",
      "chain": "ethereum", "protocol": "eigenlayer"
    }
  }'

Perps — Hyperliquid + dYdX v4

Smeltor builds the bridge2 deposit calldata when needed (HL only — dYdX is native on its app-chain), formats the limit price to the protocol's tick size, and returns the unsigned EIP-712 order body. The caller signs with the user's local agent key and POSTs to the venue. Default venue: "hyperliquid"; pass venue: "dydx" to route to dYdX v4.

curl -sX POST https://api.smeltor.com/api/public/workflow/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "0xYourWallet…",
    "action": "perp_open",
    "params": {
      "asset": "ETH", "side": "short",
      "leverage": 5, "amount": "50",
      "venue": "hyperliquid"
    }
  }'

10Factual metadata (no risk scores)

Every earn option in the response carries a facts block. We present facts; the agent decides risk. Fields: tvl_usd, audited, audit_firms[], months_live, previous_exploits[], governance, type. The earn / yield-comparison response includes a yieldComparison object with options[], highestApy, longestLive, and largestTvl so callers can rank by whichever axis matters to them.

Smeltor is a routing engine, not a financial advisor. Options are surfaced with technical descriptors (highest_yield, same_chain, fixed_rate, lowest_cost, no_bridge, primary) — never "best" or "recommended". The calling agent or end user picks.

11Try it

The fastest way to internalize the surface is the live demo — same routes, browser-side, no setup. Click around and watch real on-chain data. Toggle testnet mode at the top of the demo to preview the calldata against testnet routers.