v0

Reference for v0 REST APIs served by Espresso nodes and query services

API v0 was the default API version from genesis until the proof-of-stake upgrade. Proof-of-stake launched on testnet on April 15, 2025 and on Mainnet in March 2026, after which v1 became the default API version. v0 continues to be supported indefinitely; however, certain endpoints will fail when querying for data originating after the proof-of-stake upgrade, and fields of certain types added in the proof-of-stake upgrade are not accessible via this API.

The differences between v0and the subsequent version v1are:

• v0lacks new fields which were added to the Leaftype in v1 . For leaves created before the proof-of-stake upgrade, the leaf structure without these fields is equivalent to the new structure. However, for leaves created after the proof-of-stake upgrade, it will be impossible to compute accurate commitments or verify consensus artifacts using the v0API.

  • next_epoch_justify_qc

  • next_drb_result

  • with_epoch

• v0lacks new fields which were added to the QC type in v1 . For QCs created before the proof-of-stake upgrade, the QC structure without these fields is equivalent to the new structure. However, for QCs created after the proof-of-stake upgrade, it will be impossible to compute accurate commitments or verify consensus artifacts using the v0API.

  • epoch

• The types of VID artifacts (VID shares, VID common, and namespace proofs) are different in v0and v1. For blocks created before the proof-of-stake upgrade, the VID types are equivalent, and any proofs using these types can still be verified using the information returned by the v0API. However, the new version of the Rust SDK will not be able to deserialize the v0types, and for blocks created after the proof-of-stake upgrade, the v0endpoints will return errors.

• v0lacks all APIs related to rewards state

• v0lacks the availability/state-cert/:epochand catchup/:height/leafchainAPIs which are necessary for running a consensus client after proof of stake

• v0lacks the convenience endpoint node/stake-tablefor fetching the latest stake table from a trusted server