XLS to XLSX

What it’s for

• Exports from older systemsSoftware that still writes .xls can feed tools that only read .xlsx.
• Before parsingLibraries that handle .xlsx well get a file they understand.
• Old archivesBring a folder of old workbooks forward, one call per file.
• Quick, in lineTypical workbooks convert in well under a second, so the sync route fits.

How it runs

1. DownloadFetches the workbook from your http(s):// URL. The download times out after 30 s.
2. ReadParses the binary BIFF format. A file that is already .xlsx, or a CSV renamed to .xls, fails.
3. WriteCopies every sheet’s cell values into a new .xlsx. Formulas keep their last computed value.
4. StoreOne .xlsx file on the job.

Values only. Formatting, charts, macros and merged-cell styling don’t come across.

Input

Send these fields as input in the request body. Anything not listed is refused with 400.

The request body

What comes back

Example

curl https://api.servicelabs.dev/v1/utilities/xls-to-xlsx \
  -H "Authorization: Bearer $DU_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": {
      "url": "https://example.com/report.xls"
    }
  }'

# 1. Start the job. Answers 202 straight away.
curl https://api.servicelabs.dev/v1/utilities/xls-to-xlsx/jobs \
  -H "Authorization: Bearer $DU_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: xls-to-xlsx-0001" \
  -d '{
    "input": {
      "url": "https://example.com/report.xls"
    },
    "callbackUrl": "https://example.com/hooks/servicelabs"
  }'

# 2. Collect it by id. Long-polls for up to 60 s.
curl "https://api.servicelabs.dev/v1/jobs/job_01K7Z3Q4N5P6R7S8T9V0W1X2Y3?wait=60" \
  -H "Authorization: Bearer $DU_API_KEY"

const API = 'https://api.servicelabs.dev/v1'
const headers = {
  Authorization: `Bearer ${process.env.DU_API_KEY}`,
  'Content-Type': 'application/json',
}

// Sync: holds the connection for up to 90 s
const res = await fetch(`${API}/utilities/xls-to-xlsx`, {
  method: 'POST',
  headers,
  body: JSON.stringify({ input: { url: 'https://example.com/report.xls' } }),
})
if (res.status === 400) throw new Error((await res.json()).error.message)
let job = await res.json()

// Still running after 90 s? It carries on. Collect it by id.
while (job.status === 'queued' || job.status === 'running') {
  job = await (await fetch(`${API}/jobs/${job.id}?wait=60`, { headers })).json()
}

if (job.status === 'succeeded') console.log(job.result.files.map((f) => f.url))
else console.error(job.error.code, job.error.message)

{
  "id": "job_01K7Z3Q4N5P6R7S8T9V0W1X2Y3",
  "object": "job",
  "utility": "xls-to-xlsx",
  "mode": "sync",
  "status": "succeeded",
  "createdAt": "2026-09-10T17:30:06.650Z",
  "finishedAt": "2026-09-10T17:30:09.009Z",
  "timings": { "queueMs": 0, "upstreamMs": 2140, "storageMs": 196, "totalMs": 2359 },
  "result": {
    "files": [
      {
        "url": "https://…/1789061409_report.xlsx",
        "name": "1789061409_report.xlsx",
        "size": 18342,
        "contentType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
      }
    ]
  },
  "error": null,
  "links": {
    "self": "/v1/jobs/job_01K7Z3Q4N5P6R7S8T9V0W1X2Y3"
  }
}

{
  "error": {
    "code": "invalid_request",
    "message": "input failed validation for xls-to-xlsx",
    "details": [
      {
        "path": "input.url",
        "message": "must be an http(s) URL"
      }
    ]
  }
}

Limits

When it fails

A 400 means nothing ran. Everything else is a failed job with status: "failed", an error code and the utility’s own message.

Any call can also get 401 unauthorized, 403 forbidden (the key isn’t allowed this utility) or 429 rate_limited. The full list is in Conventions & errors.

Reference

• XLS to XLSX guideEvery option, with worked examples.
• runXlsToXlsxPOST /v1/utilities/xls-to-xlsx
• createXlsToXlsxJobPOST /v1/utilities/xls-to-xlsx/jobs
• getJobGET /v1/jobs/{id}
• JobsStatuses, timings, retries and cancelling.
• CallbacksVerifying the signature on a finished job.

Also in service

• HTML to PDF
• Split PDF
• Zip files
• Unzip archive