What is a fully on-chain NFT?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 5 min
In short
A fully on-chain NFT stores its image and metadata entirely in blockchain state rather than pointing outward. That removes any dependence on servers or IPFS, but on-chain storage is expensive and sharply limits how much data the work can contain.
Key points
- Image and metadata are held in chain state itself
- No dependency on outside servers or IPFS
- Storage is costly, so size is tightly constrained
- Often expressed as compact SVG or generating code
Definition
An NFT whose display data is stored entirely in blockchain state, with tokenURI returning data assembled on chain rather than an external URI.
A common implementation has tokenURI return a data: URI with Base64-encoded JSON embedded directly, and the JSON's image field carry an encoded SVG in the same way. The result is a token with no outward reference at all.
The constraint is cost. Writing a single storage word on Ethereum costs substantial gas, so storing a multi-megabyte image is not viable. Works are therefore expressed compactly — a few hundred bytes of SVG shapes, or a pixel palette and layout assembled at render time.
Some projects described as fully on-chain still pull in fonts or libraries from outside. Fetching the actual tokenURI output and checking it for external URLs settles whether a given collection is genuinely self-contained.
Watch out for
- · Check the actual tokenURI output — some 'on-chain' collections still load outside resources
- · If the chain itself halts or splits, access to the data is affected too
- · A better storage design has no bearing on whether anyone will buy the token