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NFT Metadata Validator

Validate NFT metadata against ERC-721, OpenSea, and Solana Metaplex standards. Preview your NFT before minting.

Free No signup Client-side Privacy friendly

Preview

How to use

  1. 1 Pick the standard your NFT targets — ERC-721 (Ethereum), OpenSea extended, or Metaplex (Solana).
  2. 2 Paste your metadata JSON into the input panel.
  3. 3 Validation runs instantly. Fix any errors before minting.

Why use this tool

  • Catches missing required fields, malformed URLs, and non-standard attributes before you mint.
  • OpenSea-style preview card so you see exactly what collectors will see.
  • Supports IPFS CIDs (Qm… and bafy…) with auto-rewrite to a gateway for preview.
  • Runs entirely in your browser — your metadata stays private.
  • Free, no signup.

Frequently asked questions

Which standards are supported?

ERC-721 (the minimum required fields), OpenSea's extended schema (background_color, animation_url, display_type attributes), and Solana's Metaplex (symbol, properties.files, creators).

Does this guarantee my NFT will appear correctly on OpenSea?

No tool can guarantee that — OpenSea has additional indexing rules and trait normalization. But passing all checks here catches the most common rejection causes.

What about ERC-1155?

ERC-1155 metadata is identical to ERC-721 with optional {id} placeholder in URIs. Use the ERC-721 mode and validate your URI template separately.

Why does my IPFS image not load in the preview?

Cloudflare's public IPFS gateway can be slow or rate-limited for some CIDs. The metadata can still be valid even if the gateway times out.

Summary

NFT Metadata Validator is a free web3 utility by Zerethon Tools. Validate NFT metadata against ERC-721, OpenSea, and Solana Metaplex standards. Preview your NFT before minting. Runs entirely in the browser — no signup, no upload.

Category
Web3
Pricing
Free
Privacy
Browser-based
Signup
Not required

Privacy

Your data never leaves your browser unless explicitly stated. NFT Metadata Validator runs entirely client-side — no server upload, no logging, no tracking of your input.

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