hucre

Zero-dependency spreadsheet engine — XLSX, CSV, ODS, JSON, NDJSON, XML

Drop an XLSX file to parse it. All cell types, shared strings, dates, and merged cells are handled correctly.

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Drop .xlsx file here or click to browse

Options

Sheets

Header Row

Read Styles

Detect Dates

Skip Hidden Sheets

Drop an XLSX file to see parsed data

Generate XLSX files from JSON data. Define columns, styles, and sheet options.

JSON Data

Sheet Options

Sheet Name

Freeze Rows

Auto Filter

Auto Width

Columns

Column Config (JSON)

Click "Generate XLSX" to preview

Parse and generate CSV with auto-delimiter detection, type inference, and RFC 4180 compliance.

CSV Input

Parse Options

Delimiter

Has Header

Type Inference

Skip Empty

Edit CSV and click Parse

Parse JSON arrays, objects with single-array properties, or NDJSON (JSON Lines). Nested objects flatten into dot-path keys. Round-trip back to NDJSON or XLSX.

Mode

JSON

NDJSON

Input

Parse Options

Flatten Nested

Array Join

rowsAt path (optional)

Edit input and click "Parse"

Read tabular XML — auto-detects the most-frequent repeating element as the row tag. Attributes prefix with @. Use cases: GS1 GDSN, Trendyol, SAP B1, Logo GO, Netsis, marketplace product feeds.

XML Input

Parse Options

rowTag (auto if empty)

attrPrefix

Flatten

Strip Namespaces

Edit XML and click "Parse"

Validate spreadsheet data against a schema. Type coercion, pattern matching, min/max, enums.

Sample Data (CSV)

Schema Definition (JSON)

Click "Validate" to check data against schema

Stream large XLSX files row-by-row without loading everything into memory. Or generate XLSX incrementally with XlsxStreamWriter.

Generate & Stream

Number of rows to generate

Number of columns

Click "Generate & Stream" to write and read back rows

Stream from File (ReadableStream)

Drop an .xlsx file to stream-read it via ReadableStream<Uint8Array>. Compares streaming vs buffered read performance.

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Drop .xlsx file here or click to browse

Drop an .xlsx file to stream rows via ReadableStream

Auto-split past Excel's 1,048,576-row limit

When maxRowsPerSheet is reached, the writer rolls over to {name}_2, {name}_3, … with the captured header repeated.

Total rows to write

maxRowsPerSheet

Repeat header on each sheet

Click "Generate & Split" to see how rows roll over to new sheets

Read and write OpenDocument Spreadsheet (.ods) files — compatible with LibreOffice, Google Sheets, and other open-source tools.

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Drop .ods file here or click to browse

Or generate ODS from JSON

Drop an ODS file or click "Generate ODS"

Convert XLSX, CSV, or ODS files to HTML table or Markdown format.

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Drop .xlsx, .csv, or .ods file

Or paste CSV

Options

First Row as Header

Include Styles (HTML)

Drop a file or paste CSV, then click "HTML" or "Markdown"

Apply Excel number formats to values. formatValue(value, numFmt) renders any cell value with its format string.

Value

Format String

Quick Examples

Click "Format" or pick a quick example

Drop a template .xlsx with one or more charts. Hucre lists every chart it finds via getCharts(workbook), then lets you tweak per-chart knobs and re-emit the workbook through cloneChart + addChart + writeXlsx. Refs #136.

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Drop .xlsx file with charts (or click to browse)

Output

Mode

Destination Sheet

New sheet name (when "New")

Drop an XLSX file containing charts to see them listed here