A Stirling PDF Alternative: What Matches and Where Your File Goes
On October 21, 2026, we matched the 56 tools listed in Stirling PDF's docs against PulsarKit. 28 had a counterpart, 4 matched only in part and 24 had none, from editing existing text to certificate signatures.
By PulsarKit ·
Three ways to run Stirling PDF
Stirling PDF is a PDF editor from Stirling PDF Inc. On October 21, 2026, its home page called it “a free, private PDF editor you can run on any infrastructure”. Its pricing page listed a free plan for individuals with “60+ PDF tools”. A Team plan cost $99 a month for 100 users.
There are three ways to run it. Its docs say the desktop app for Windows, Mac and Linux runs most tools on your own computer, with no account. You can also host it on your own servers or cloud account, where the free plan covers up to five users.
The third is Stirling Cloud, Stirling PDF hosted online at stirling.com/app. That day it opened on a sign-in page with a Skip button. Its docs say guests can use every manual PDF tool, while AI tools, automation and the API need an account. Manual tools are free, and automation, AI and API calls use credits.
PulsarKit is a website with more than 200 free tools for files. There is nothing to install, and there is no sign-up, subscription or payment form. The site is paid for by advertising.
28 of 56 Stirling tools, checked on October 21, 2026
The All tools page of Stirling's docs lists 56 tools in 12 groups, “grouped as the tool picker shows them”. Their site says 60+ and their GitHub README says 50+, so we counted the docs list. For each tool we looked for a PulsarKit tool that gives the same result, not identical features. Both sites change, so this is a count on one date.
At that check, 28 of the 56 had a counterpart. Merge, Split, Rotate, Crop PDF, Extract Pages, Extract Images, Remove Pages, Compress and Compare match one to one. So do Redact, Sign, Flatten, Annotate, Add Password, Add Watermark, Add Page Numbers, Repair and OCR / Cleanup scans. Remove Blank pages matches the Blank pages option of our Delete pages tool, and Multi-Page Layout matches our N-up tool.
Eight more match through tools with other names. Their Page Editor rotates, reorders, deletes, splits and inserts blank pages; here that takes Organize PDF, Split PDF and Insert blank page. Organize PDF alone covers Reorganize Pages. Our Edit PDF covers Add Text and Add image. Watermark PDF places a text or image stamp in a corner, like Add Stamp to PDF. Read matches PDF Viewer, Form Editor matches PDF Forms, and Remove Password matches Unlock PDF, which also needs the password.
Four more match only in part and are not counted. Convert is one tool for dozens of formats, covered below. Change Permissions works here only together with an open password, in Protect PDF. Auto Rotate exists here only as an option of OCR PDF. Automate runs saved steps on files in one go. Our saved chains repeat a run on a new file, one step at a time.
What Stirling PDF has and PulsarKit does not
The other 24 had no counterpart. One gap is editing: their PDF Text Editor changes the existing text and images in a PDF. Our Edit PDF adds text and images on top of the page and cannot rewrite what is already there.
Signatures go further there too. Sign with Certificate adds a digital signature, Timestamp PDF adds an RFC 3161 timestamp, and Validate PDF Signature checks a signed file. Our Sign PDF places a drawn or typed signature, or a photo of one, with no certificate.
The rest are specialist tools for bookmarks, attachments, portfolios, booklets, overlays, page size, colours and metadata. Stirling can also remove JavaScript or every image from a file and find form fields on a flat page by itself.
The product differs as well. Stirling is open-core: its code is on GitHub under the MIT License, except folders that carry their own license. It has a desktop app, a REST API and automated pipelines, and its README lists an interface in 40+ languages. PulsarKit has no desktop program, no version for your own server and no API.
Where your file goes
On Stirling Cloud, their docs place viewing, reading and rearranging pages in your browser. “Server tools such as compress, OCR, convert and watermark” are “Sent to Stirling's servers, processed and returned”. The cloud runs on Amazon Web Services, and their Compare guide says that tool runs on your device.
Their docs say the desktop app in Local Only mode uploads nothing, and a tool it cannot run is blocked. They list OCR, Office and eBook conversions and Repair among tools that usually need Stirling Cloud or a server. On a self-hosted server, every tool runs on that server.
On PulsarKit, 26 of the 28 counterparts ran in the browser that day, so the file stayed on your device. That includes Compress PDF and Watermark PDF, which Stirling Cloud sends to its servers. OCR PDF and Repair PDF ran on our server, the same kind of jobs that Stirling's desktop app hands to a server.
Each of our server tool pages says the file is deleted after processing and the result is wiped within about two hours. Those tools take files up to 300 MB, with up to 30 jobs an hour.
Convert, format by format
Stirling's Convert guide lists 28 formats it turns into PDF, counting JPG and JPEG once, and 24 targets it makes from a PDF. On October 21, 2026, PulsarKit had a converter for 19 of the 28 and for 13 of the 24.
Into PDF, we cover Word, Excel, PowerPoint, OpenDocument, RTF, TXT, Markdown, HTML, EPUB and five image formats. Missing were BMP, SVG, EML and MSG email files, MOBI, AZW3, FB2, and CBZ and CBR comics.
From a PDF, we make Word, ODT, RTF, Excel, CSV, PowerPoint, text, Markdown, JPG, PNG, TIFF, PDF/A and EPUB. Missing were ODP, GIF, BMP, WebP, HTML, XML, PDF/X, PDF/UA, AZW3, CBZ and CBR.
Here the image and text conversions run in your browser, while Office files, HTML, EPUB and PDF/A go to our server. Of these 32 conversions, 12 ran in the browser and 20 on the server, PDF to Word among them.
Which one fits
If documents must stay inside your own network, Stirling on your own server or desktop does what PulsarKit cannot. That includes OCR and Office conversions on servers you control, certificate signatures, editing existing text, an API and automated runs.
If you need one job done on a phone or a borrowed computer, PulsarKit needs no install and no account. Most of its tools run in the browser, and it also handles images, video, audio and text. A list of next tools under each result passes the file straight on.
Tools used in this article
Compress PDFMake a PDF smaller by re-encoding the images inside it, dropping duplicated objects and clearing metadata, without sending the document anywhere.
Edit PDFPut text, images, shapes and white-out boxes on any page and save the result as a PDF, without the file ever leaving your device.
OCR PDFTurn a scanned PDF into one you can search and copy text from. Runs on our server; files are deleted automatically within about two hours.
Organize PDFPut the pages of a document in the order you want, and rotate, duplicate or drop individual pages along the way.
Watermark PDFStamp a word or a logo across every page, tiled or in one spot, with the opacity, angle and layer you choose.
PDF to WordTurn a PDF back into an editable DOCX, DOC, ODT or RTF file, with OCR for scans that have no text layer at all. Runs on our server; files are deleted automatically within about two hours.Read next
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