Parquet vs JSON for Blockchain Data Exports
Choose columnar or record-oriented exports based on query patterns, schema needs and exact quantity handling rather than file extension alone.
Overview
When translating these concepts into an integration, keep the scope described by the wallet history api with the result. The examples in wallet transaction history and smart contract event logs show how the same distinction affects neighbouring data questions.
JSON and Parquet serve different workflows. JSON is convenient for inspecting individual records; Parquet can suit column-oriented analytical scans. The right choice depends on the consumer and data contract.
Compare access patterns
A JSON API can deliver nested transaction evidence naturally, but repeated text keys add overhead. Parquet stores typed columns with encoding and compression choices useful for analytical reads. Neither format automatically preserves the meaning of token units or event identities. Publish the schema and numeric representations in either case.
Worked example: reading two columns
An analyst needs event time and raw quantity from a large transfer export. A columnar reader can avoid loading many unrelated columns when the file layout and query engine support that access. A debugging tool inspecting one complete transaction may prefer a bounded JSON record with its nested evidence.
Test interoperability
Include large integers, nullable fields, schema evolution and timestamp precision. Confirm that the receiving engine interprets decimal and binary fields correctly. Do not downcast a 256-bit quantity into a smaller integer merely to fit a convenient column type. Version exports and retain enough metadata to explain their network and coverage boundaries.
A practical acceptance test
Export identical synthetic evidence in JSON and the selected typed columnar schema. Read both with the intended consumers and compare exact identities, quantities and timestamp precision. Include null metadata and a quantity wider than common machine integers. A smaller file is not a successful export if the receiving engine silently downcasts the amount or changes its units.
Questions about the topic
Frequently asked questions
Does Parquet solve unit ambiguity?
No. Typed storage still needs an explicit semantic schema.
Should all consumers receive the same format?
No. Inspection and analytical scanning can justify different representations.
Standards & technical documentation
