Interact with any contract
on any EVM chain.
gulltoppr resolves a usable ABI for any address — including the ones nobody verified, straight from bytecode — then lets an agent read, simulate, and prepare transactions with provenance it can actually reason about.
Resolve any contract, right now
Runs against the live engine at api.gulltoppr.dev from your browser — no key, no signup.
Paste an unverified address: it still resolves, and tells you the ABI was decompiled.
Advanced — use your own RPC endpoint
Five rungs, and it never gives up at rung one
Every answer carries provenance — source, confidence, and whether names were inferred — so an agent knows exactly how much to trust the interface it just got.
Etherscan
Verified source and ABI where the explorer has it.
Sourcify
Open, decentralized verification as the second opinion.
Proxy hop
EIP-1967, beacon, and diamond patterns followed to the implementation.
Decompile
heimdall lifts an interface out of raw bytecode when there is no source at all.
4byte
Selector lookup as the floor — you still get callable signatures.
Then use it: resolve_abi · read_contract · encode_call ·
simulate · prepare_tx · decode_tx · resolve_name.
prepare_tx returns an unsigned transaction, a wallet request, a simulation, and warnings — signing stays with the user.
An agent resolving a live unverified MEV bot
No source on Etherscan, nothing on 4byte, trading seconds earlier — resolved to a full interface in two MCP tool calls, with a provenance warning attached. That exact contract is the first example chip above.
Three ways in
Point an agent at the MCP endpoint, install the typed SDK, or just curl it.
{
"mcpServers": {
"gulltoppr": { "url": "https://mcp.gulltoppr.dev/mcp" }
}
}
Drop it into Claude Code, Claude Desktop, Cursor, or any MCP client. Wallet, explorer, and coding-agent recipes live in the integration guide. Prefer to run it yourself? npm run mcp (stdio) or npm run mcp:http.
npm i gulltoppr import { Gulltoppr } from "gulltoppr"; const g = new Gulltoppr(); const r = await g.resolveAbi("base", "0x833…2913"); // r.interface.reads / .writes, r.provenance, r.proxy const tx = await g.prepareTx("base", addr, "transfer", [to, "1000000"], { from: myWallet }); // → unsigned tx + wallet request + simulation + warnings // (it never signs)
Typed, zero-config, works in Node and the browser. gulltoppr on npm.
curl 'https://api.gulltoppr.dev/v1/base/0x833…2913/abi?include_abi=false' # same ladder, same provenance, no SDK required # OpenAPI spec: https://api.gulltoppr.dev/openapi.json
Plain HTTP, CORS-enabled — which is exactly how the playground above talks to it.