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Omniparser is a native Golang ETL parser that ingests input data of various formats (CSV, txt, fixed length/width, XML, EDI/X12/EDIFACT, JSON, and custom formats) in streaming fashion and transforms data into desired JSON output based on a schema written in JSON.

Please kindly consider sponsoring the project to fund future development and issue resolutions:

Min Golang Version: 1.14





In the example folders above you will find pairs of input files and their schema files. Then in the .snapshots sub directory, you'll find their corresponding output files.

Online Playground

Use (may need to wait for a few seconds for heroku instance to wake up) for trying out schemas and inputs, yours or existing samples, to see how ingestion and transform work.


  • No good ETL transform/parser library exists in Golang.
  • Even looking into Java and other languages, choices aren't many and all have limitations:
    • Smooks is dead, plus its EDI parsing/transform is too heavyweight, needing code-gen.
    • BeanIO can't deal with EDI input.
    • Jolt can't deal with anything other than JSON input.
    • JSONata still only JSON -> JSON transform.
  • Many of the parsers/transforms don't support streaming read, loading entire input into memory - not acceptable in some situations.


  • Golang 1.14 or later.

Recent Major Feature Additions/Changes

  • 2022/09: v1.0.4 released: added csv2 file format that supersedes the original csv format with support of hierarchical and nested records.
  • 2022/09: v1.0.3 released: added fixedlength2 file format that supersedes the original fixed-length format with support of hierarchical and nested envelopes.
  • 1.0.0 Released!
  • Added Transform.RawRecord() for caller of omniparser to access the raw ingested record.
  • Deprecated custom_parse in favor of custom_func (custom_parse is still usable for back-compatibility, it is just removed from all public docs and samples).
  • Added NonValidatingReader EDI segment reader.
  • Added fixed-length file format support in omniv21 handler.
  • Added EDI file format support in omniv21 handler.
  • Major restructure/refactoring
    • Upgrade omni schema version to omni.2.1 due a number of incompatible schema changes:
      • 'result_type' -> 'type'
      • 'ignore_error_and_return_empty_str -> 'ignore_error'
      • 'keep_leading_trailing_space' -> 'no_trim'
    • Changed how we handle custom functions: previously we always use strings as in param type as well as result param type. Not anymore, all types are supported for custom function in and out params.
    • Changed the way how we package custom functions for extensions: previously we collect custom functions from all extensions and then pass all of them to the extension that is used; This feels weird, now changed to only the custom functions included in a particular extension are used in that extension.
    • Deprecated/removed most of the custom functions in favor of using 'javascript'.
    • A number of package renaming.
  • Added CSV file format support in omniv2 handler.
  • Introduced IDR node cache for allocation recycling.
  • Introduced IDR for in-memory data representation.
  • Added trie based high performance times.SmartParse.
  • Command line interface (one-off transform cmd or long-running http server mode).
  • javascript engine integration as a custom_func.
  • JSON stream parser.
  • Extensibility:
    • Ability to provide custom functions.
    • Ability to provide custom schema handler.
    • Ability to customize the built-in omniv2 schema handler's parsing code.
    • Ability to provide a new file format support to built-in omniv2 schema handler.