# Reference The Open Contracting Data Standard is maintained using JSON Schema. In this section you will find the schema for [releases](release) along with the schemas for [release packages](release_package) and [record packages](record_package), which act as envelopes for releases and records, respectively. The [release schema reference](reference) provides guidance on using each of the [sections](reference.md#release-structure) and [building blocks](reference.md#building-block-reference) in the schema, and the [record schema reference](records_reference) provides additional information on publishing records with compiled and versioned releases. OCDS data must follow the I-JSON (Internet JSON) specification in [RFC7493](https://tools.ietf.org/html/rfc7493), according to which JSON text must be encoded using [UTF-8](https://en.wikipedia.org/wiki/UTF-8), and which introduces a number of requirements for numbers, objects and dates. ```{toctree} :hidden: reference release release_package records_reference record_package merging identifiers codelists conformance_and_extensions ```