What fields does ERC-721 metadata require?

The widely-supported schema uses name, description and image, plus an optional attributes array of trait objects. Marketplaces like OpenSea read these directly, so a valid file needs at least those three top-level fields with a reachable image URL.

Should the image link be IPFS or HTTPS?

For permanence, pin the image to IPFS and use an ipfs:// URI so the art cannot disappear if a server goes down. An HTTPS gateway URL also works and is sometimes easier for previews, but it depends on that host staying online.

How are attributes formatted?

Each attribute is an object with trait_type and value, for example { "trait_type": "Model", "value": "SDXL" }. Numeric traits like the seed can include a display_type of number. Marketplaces use these to build filters and rarity tables.

Why record the prompt and seed?

The prompt and seed make a generative piece reproducible and provable. Storing a prompt hash (rather than the full prompt) keeps the recipe private while still letting you prove provenance later by revealing the original prompt.

What is the AI Art NFT Metadata Builder?

Form-based builder for ERC-721 NFT metadata. Enter name, description, image URL and AI generation attributes (model, prompt, seed, style) to produce standards-compliant, OpenSea-ready metadata JSON. It runs free in your browser on Gera Tools, with nothing uploaded.

AI Art NFT Metadata Builder

Name: AI Art NFT Metadata Builder
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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AI art NFT metadata builder

Minting AI artwork as an NFT needs a metadata JSON file that marketplaces read to display the piece. The de-facto standard is the ERC-721 metadata schema — name, description, image, and an attributes array. This builder collects your fields and AI generation details and outputs a clean, compliant file ready to pin to IPFS.

How it works

You fill in the core fields and any generation attributes — model, seed, style and a prompt hash. The tool assembles them into a valid ERC-721 object, encoding each attribute as a { trait_type, value } pair so OpenSea and similar marketplaces can build filters and rarity tables. The seed is marked as a numeric display type. The output is pure, parseable JSON with no trailing commas or invalid fields.

Understanding the ERC-721 metadata schema

The ERC-721 standard defines what a token is but says nothing about what it looks like. The community converged on a metadata schema that extends the contract:

{
  "name": "My AI Artwork #1",
  "description": "A description of the piece.",
  "image": "ipfs://Qm...",
  "attributes": [
    { "trait_type": "Model", "value": "SDXL" },
    { "trait_type": "Seed", "value": 42, "display_type": "number" },
    { "trait_type": "Style", "value": "photorealistic" }
  ]
}

The image field holds a URI to the artwork itself — ideally an ipfs:// content-addressed URI rather than an HTTPS link, so the image remains accessible independently of any single server. The attributes array is where AI generation details belong; marketplaces read these to build trait filters and rarity distributions.

Why AI-specific attributes matter

Recording the model, seed, and style in the metadata does several things for AI artwork specifically:

Provenance. A collector or auditor can verify which generative model produced the piece, which is increasingly relevant as platforms develop policies around AI-generated content.
Reproducibility. A documented seed means the image can be regenerated from the same model to confirm authenticity, at least while that model version remains available.
Rarity mechanics. For a generative collection, traits like model, sampler, or style can drive rarity tables the same way hand-drawn trait layers do.
Prompt privacy. Storing a cryptographic hash of the prompt lets you prove the exact prompt later (by revealing it and showing it matches the hash) without exposing the recipe to competing creators while the work is current.

Tips and notes

Pin to IPFS for permanence. Use an ipfs:// URI for the image so the art outlives any single server.
Store a prompt hash, reveal later. Keep the exact prompt private while still being able to prove provenance.
Use numeric display types for the seed and any edition number so marketplaces sort them correctly.
Validate before minting. Paste the output into a JSON validator — a single malformed character can make a marketplace fail to render your token.
Save the raw prompt separately. Metadata is immutable once minted; keep the original prompt and seed in a secure record off-chain so you can reconstruct or prove it later.