Chains API

Is this compressed address still free, and what proves it

Says whether one address is still unused in a Solana ZK-compression address tree, and returns the non-inclusion proof — root, neighbours and Merkle path — a program needs to create it there.

GET/api/external/chain-analysis/compressed-address-proof/{chain}/{address}

Get a free API key Try it in the API reference

What it returns

Answers whether one address is still unused in a Solana ZK-compression address tree, and when it is, returns the non-inclusion proof a program needs to create it: the tree root and its sequence number, the two addresses the new one would sit between, their leaf indexes and the Merkle path. unused: false is a full answer, not an error — the tree already holds the address and nobody can create it again — and it carries no proof. Name a tree to ask about one address tree; with none, the default address tree is used and named back in tree. The answer is about that ONE tree: a compressed account's address does not have to live in the default tree, so unused: true there does not mean no account uses the address on Solana. The proof is read at the slot in slot and ages with the tree: every compressed address anyone creates moves the root, so submit it promptly or ask again.

Chains

Solana SOL

Request

Send your key in the x-dex-data-key header. Replace each <placeholder> with a real value.

curl -H "x-dex-data-key: $DEXDATA_API_KEY" \
  "https://api.dexdata.io/api/external/chain-analysis/compressed-address-proof/SOL/<address>"

Parameters
Parameter	Description
`tree` query · string · optional	The address tree to ask about, base58. Omit it for the default address tree. An address that is not an indexed address tree returns 400.
`chain` path · string · required	SOL. Every other chain returns 400: compressed addresses live in an address tree, a Solana construct.
`address` path · string · required	A base58 32-byte address in a ZK-compression address tree, typically derived from a seed before anything is created at it. Not a wallet or contract address in the ordinary account space: an address tree is its own namespace, and the same value in two trees is two addresses.

Response fields

A JSON response. Every field is always present; null means the value could not be established, never zero.

Response fields of Is this compressed address still free, and what proves it
Field	Type	Description
`address`	string	The address asked about.
`tree`	string \| null	The address tree the answer is about. Null only when the address is already taken in the default tree: the answer to that is a refusal, which names no tree.
`unused`	boolean	True when THIS tree does not hold the address yet, so a program can still create it in this tree. Says nothing about any other address tree: an address already used by a live account in another tree still reads true here.
`slot`	integer \| null	The slot the tree was read at; null on the refusal described under `tree`.
`proof`	object \| null	The non-inclusion proof. Null whenever `unused` is false: a taken address has nothing to prove.
`proof.root`	string	The tree root this proof verifies against.
`proof.rootSeq`	integer	That root's sequence number; it moves every time the tree changes.
`proof.lowerRangeAddress`	string	The largest address in the tree below the one asked about.
`proof.higherRangeAddress`	string	The next address above it. The highest element's neighbour wraps to the all-zero address.
`proof.lowElementLeafIndex`	integer	The leaf index of `lowerRangeAddress`.
`proof.nextIndex`	integer	The next pointer stored on `lowerRangeAddress`: the leaf index of `higherRangeAddress`. Not the index the new address would take.
`proof.path`	string[]	The sibling hashes from that leaf up to the root, bottom first.

Price per call

Solana: 21 credits

Charged only when the call succeeds. Prices as of 2026-10-30; the current ones are always in the API reference.

Blocks a validator or builder produced
Same inputs: address, chain.
The address lookup tables an authority controls
The other Solana-only construct a transaction builder reads before it submits.
Transactions that touched ZK-compressed state on Solana
The other ZK-compression read: whether an address is still free to create.
Which ZK-compressed accounts a wallet or program holds
One reads the compressed accounts that exist, the other proves an address is still free to create one.
What one Solana slot did
One named slot: whether its leader produced a block, who led it, its transactions split into votes and user traffic, how many failed, the fees paid, and for a recent slot the stake voted on it.
The newest validator deposits on Ethereum
The newest beacon-chain validator deposits accepted on Ethereum (validator public key, amount, withdrawal address, status) and the total number accepted so far.

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