Integration

Token metadata

How a coin's description, image and links are encoded at launch, and how to read them back.

A coin's name and symbol are ERC-20 fields. Everything else a creator enters, the description, the image and the links, travels as the tokenData argument of LauncherFactory.launch, is stored on chain once, and cannot be changed afterwards.

Encoding

tokenData is the ABI encoding of one tuple. Send 0x when there is no metadata at all: the factory accepts it, whereas bytes it cannot decode revert the launch.

import { encodeAbiParameters, toHex } from "viem";

const tokenData = encodeAbiParameters(
  [{ type: "tuple", components: [
    { name: "description", type: "string" },
    { name: "website",     type: "string" },
    { name: "image",       type: "string" },
    { name: "extraData",   type: "bytes"  },
  ] }],
  [{
    description: "The bull that never sleeps.",
    website: "https://bullcoin.example",
    image: "https://…/bull.webp",
    extraData: toHex(JSON.stringify({
      x: "https://x.com/bullcoin",
      telegram: "https://t.me/bullcoin",
      website: "https://bullcoin.example",
    })),
  }]
);

Field	What goes in it
description	Plain text, shown on the coin's page.
website	One URL. The coin's own site when it has one, otherwise its X link, then Telegram. Older launches put an X or Telegram URL here, so classify it by host before drawing it as a website.
image	An absolute `https` URL, stored on chain as written. PNG, JPEG or WebP; square, around 600px, is what every surface draws.
extraData	UTF-8 JSON, hex-encoded, with any of `x`, `telegram`, `website` as full URLs. The contract never reads it; it exists so a launch can carry more than one link. Empty is `0x`.

Reading it back

The indexer decodes all of it: token { name symbol image description } plus the links, on the same GraphQL API the app uses (see Indexer API). From the chain alone, decode tokenData from the TokenLaunched event or the launch transaction's input.

Treat every field as untrusted input: it is whatever the creator typed. Allow only http and https links, and never render the description as HTML.