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PLXI specification
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Specification

PLXI file format, version 6: specification
Document PLXI file format, version 6: specification
Revision 6.0 (2026-10-01; amended 2026-10-06)
Applies to file format 6

Contents

  1. 1. Scope and conventions
  2. 2. File layout
  3. 3. Header line
  4. 3.1 Grammar
  5. 3.2 Semantics
  6. 3.3 Final and placeholder headers
  7. 4. Body: JSONL records
  8. 4.1 Lines
  9. 4.2 The record envelope
  10. 4.3 Typed records
  11. 4.4 Opaque records (forward compatibility)
  12. 5. Kind registry
  13. 5.1 Typed kinds (19)
  14. 5.2 Reserved kinds
  15. 5.3 Identity, sort order and dedup key
  16. 5.4 Payload binding targets
  17. 6. Integrity: SHA-256 coverage
  18. 7. Appendix: embedded CSDT container
  19. 7.1 What it is
  20. 7.2 Version bytes (not published)
  21. 7.3 Container checks (not published)
  22. 7.4 Section descriptor fields PLXI uses (not published)
  23. 8. Operations
  24. 8.1 Merge
  25. 8.2 Diff
  26. 8.3 Shard
  27. 9. Verify algorithm
  28. 10. Footer byte table and canonical JSON
  29. 10.0 Footer byte table (96 bytes)
  30. 10.1 Emitted bytes: one member order for every build
  31. 10.2 Value spelling
  32. 10.3 Identity form
  33. 10.4 Relation to RFC 8785 (JCS)
  34. 11. Transport encoding: .plxi.gz
  35. 12. Versioning
  36. 12.1 File format version
  37. 12.2 Record versions
  38. 12.3 Spec revisions
  39. 13. Differences from the reference implementation (not published)
  40. 14. Conformance levels
  41. 15. Reserved (not published)
  42. 16. References

The whole specification on one page

Conventions in brief

Section 1 is normative; this list only points to it. Section 1, Scope and conventions

  • The key words MUST, SHOULD, MAY and the rest are used as BCP 14 defines them, and only when written in capitals.
  • Byte offsets count from zero, from the first byte of the file. L is the length of the file in bytes.
  • Binary integers are little-endian and unsigned unless a rule says otherwise.
  • Grammar is ABNF. Every case-sensitive literal is written as byte values.
  • SHA-256 is as in FIPS 180-4. CRC32C is the Castagnoli checksum.
  • A section labelled “This section is informative” states no requirement. Every other numbered section is normative.

Scope of this publication

This publication covers the format, its records, verification and operations. Section numbers and ids match the full text. This publication leaves out:

A reader that meets a record whose kind it does not know keeps that record whole, as an opaque record. That includes the ten further reserved names.

Kinds 8 to 18 are typed. Section 5.1 gives each rank and primary id, which sorting, merging and comparing use.

© 2020-2026 Cintile Inc. All Rights Reserved.

Anyone may implement this format. Copying or republishing the text of this specification requires permission from Cintile Inc.

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