Document previews for your product — one container, no fonts to hunt.

You have a folder of Word and Excel files and want thumbnails and a readable view without installing an office suite. SumOffice Preview is one 224 MB container: post a file, get a PNG thumbnail, HTML pages or a PDF back in milliseconds. Fonts with Office metrics are inside, so text never turns into squares; the engines are the same SumDoc and SumSheet that power this site.

docker run -d -p 8099:8099 hissih/sumoffice-preview
curl -F file=@report.docx http://localhost:8099/thumb?w=320 > thumb.png    # first page, PNG
curl -F file=@report.docx http://localhost:8099/pages > report.html        # all pages, one HTML file
curl -F file=@report.docx http://localhost:8099/pdf   > report.pdf
curl -F file=@book.xlsx   http://localhost:8099/thumb > book.png           # first sheet as a grid
curl -F file=@book.xlsx   http://localhost:8099/pages > book.html          # every sheet as a table

Try it on your file

↥ Drop a Word or Excel file here or click to choose — .docx, .doc, .odt, .xlsx, .xlsm, .xlsb, .xls, up to 50 MB

The file goes to one server of ours, is rendered once and deleted before the response is sent. This box calls exactly the same service that runs in the container.

What you get back

• POST /thumb?w=320 — PNG of the first page (Word) or the first sheet as a grid of values (Excel). Width from 64 to 2000 px.
• POST /pages — a self-contained HTML file: real pages for Word, every sheet as a table for Excel. Opens from disk, no server needed.
• POST /pdf — PDF with fonts embedded, from the same layout engine as the SumDoc editor. Workbooks answer 415 for now; the engine has no PDF for sheets yet.
• Send multipart (file) or the raw bytes with ?name=report.docx. GET /health tells you which engines are inside.

Honest by contract

Every answer carries headers that say what happened: X-Preview-Pages (page count from the full layout), X-Preview-Coverage: 3/27 pages and X-Preview-Partial: true when the HTML viewer drew fewer pages than the PDF, X-Preview-Scripts-Outside-Font when the document uses a script the built-in font does not cover, X-Preview-Sheets and X-Preview-Uncomputed-Formulas for workbooks. Unknown formats get 415 with a sentence a person can read — presentations say SumPoint, December 2026, not a stack trace.

Why we built it

Two years ago the founder of Layers wanted thumbnails and a read-only view for the files people keep in their workspace. Apache POI and docx4j weighed hundreds of megabytes and drew squares instead of letters until fonts were found by hand; OnlyOffice DocumentBuilder needed a license, sessions and a week of integration. The files stayed as generic icons. This container is the answer we wished we had: docker run, one class in Java, done.

Questions

Is it free?

Evaluation is free with no time limit from us; view-only use (thumbnails, pages) stays free. Production use inside a product is licensed per embedding application or per volume — see licensing.

Does it phone home or keep files?

No. The container needs no network after docker pull; each request's files are deleted right after the response.

How big and how fast?

224 MB image; measured on 20 files of our corpus: a thumbnail in 0.3–0.6 s under x86 emulation on a laptop, under 0.1 s natively on a server. Two engines, ~250 MB of RAM per concurrent document.

PowerPoint?

Not yet: SumPoint, the third editor, is planned for public beta in December 2026; the service says so in its 415 answer.

The same engines as a server for editing: editors as a server. Inside your mobile app: view-SDK. For agents and scripts: developers.