Binary.InferContentType

Binary

Infers the MIME content type and optional encoding information from a binary stream.

Syntax

Binary.InferContentType(source as binary) as record

Parameters

Name	Type	Required	Description
`source`	`binary`	Yes	The binary stream to inspect for content type inference.

Return Value

record — A record containing Content.Type (MIME type) and optionally Content.Encoding and Csv.PotentialDelimiter or Csv.PotentialPositions.

Remarks

Binary.InferContentType inspects a binary stream and returns a record with a Content.Type field containing the inferred MIME type (e.g., "text/csv", "application/json").

Additional fields may be present depending on the inferred type:

If the content type is text/* and an encoding code page is detected, the record includes a Content.Encoding field with the encoding.
If the content type is text/csv with a delimited format, the record includes a Csv.PotentialDelimiter field containing a table of potential delimiter characters for further analysis.
If the content type is text/csv with a fixed-width format, the record includes a Csv.PotentialPositions field containing a list of potential column positions.

This function is useful when processing binary data from unknown sources and you need to determine the format before parsing.

Examples

Example 1: Infer the content type of a CSV-like binary

let
    CsvData = Text.ToBinary("Name,Age#(lf)Alice,30#(lf)Bob,25"),
    Inferred = Binary.InferContentType(CsvData),
    ContentType = Inferred[Content.Type]
in
    ContentType

Applied Steps

Extracts the Content.Type field from the inferred record, yielding "text/csv".

	Value
1	text/csv

Compatibility

✓ Power BI Desktop✓ Power BI Service✓ Excel Desktop✓ Excel Online✓ Dataflows✓ Fabric Notebooks