Unable to replicate it. Please try to follow my steps so we can isolate the issue.
Running jsreport docker image docker run -p 5488:5488 jsreport/jsreport:2.1.1 Create template test with xlsx recipe and content {{#xlsxAdd "xl/worksheets/sheet1.xml" "worksheet.sheetData[0].row"}} <row> <c t="inlineStr"><is><t>Hello world</t></is></c> <c><v>11</v></c> </row> {{/xlsxAdd}} {{{xlsxPrint}}} Create client which remotely render report const client = require('jsreport-client')('http://localhost:5488') const fs = require('fs') async function run() { const report = await client.render({ template: { name: 'test' } }) report.pipe(fs.createWriteStream('out.xlsx')) } run().catch(console.error)The output file out.xlsx can be open in the ms excel.