PDFKit is a JavaScript library for drawing PDFs imperatively, in Node or the browser: move here, set a font, write this string, draw that rectangle. It is free under the MIT license, and it has been generating PDFs for over a decade. Polotno SDK approaches the same output from the other end, with a declarative JSON schema and an editor that produces it. The choice comes down to who authors the layout.
Pick the one that matches how your layouts are made
Pick PDFKit if…
- A developer owns the layout and it rarely changes. An invoice whose shape is fixed in code is a perfectly good fit, and adding a design tool on top would be overhead.
- You want zero licensing cost. It is MIT, with no key and no quote to wait for.
- You need imperative control over the document. Precise cursor positioning, custom flow logic, and per-primitive control are natural in code and awkward in a schema.
- You are generating documents nobody designs. Receipts, logs, statements, and reports that come out of data and never pass a designer.
- The file needs PDF-native features. Fillable forms, annotations, encryption, outlines, PDF/A, and tagged PDF/UA output are all in the library.
Pick Polotno SDK if…
- Someone who is not a developer needs to change the layout. A marketer moving a logo should not require a deploy. That is the gap the editor fills.
- Your users design the document themselves. PDFKit has no editing surface and is not trying to have one.
- Templates need to live in a database. A design is JSON, so it is queryable, diffable, and versionable as data rather than as source code.
- You need more than PDF. The same schema exports PNG, JPEG, SVG, HTML, PPTX, GIF, and MP4 in the browser or on your own servers.
- You need press-ready files. Bleed, crop marks, PDF/X-4, and PDF/X-1a are built in. PDFKit handles CMYK and spot colors and leaves the rest to you.
Writing instructions vs describing a result
1. Imperative against declarative
PDFKit is a sequence of instructions:
doc.fontSize(24).text("Invoice", 50, 50);
doc.fontSize(12).text(customer.name, 50, 90);Polotno is a description of the result:
{ type: "text", text: "Invoice", x: 50, y: 50, fontSize: 24 }The instruction list is more flexible. The description is easier to generate, store, hand to a non-developer, and render into other formats.
2. Who can change a layout
This is usually the deciding question. With PDFKit, changing where the logo sits is a code change, a review, and a deploy. With Polotno, it is a drag in an editor and a new row in a table.
3. Reading PDFs
PDFKit writes only. Polotno also reads, through @polotno/pdf-import, so an existing document can be brought in and edited. See PDF editing.
Feature comparison
| Capability | Polotno SDK | PDFKit |
|---|---|---|
| Model | Declarative JSON design | Imperative drawing API |
| Who changes a layout | Non-developers, in an embedded editor | A developer, in code |
| Reads existing PDFs | Yes, through a separate package | No, writes only |
| Output | PNG, JPEG, PDF, PPTX, GIF, MP4, plus SVG and HTML outside Cloud Render | |
| CMYK and spot colors | Yes | Yes |
| Bleed, crop marks, PDF/X | Built in | Not built in |
| Fillable forms, annotations, encryption | Not documented | Built in |
| PDF/A, PDF/UA, tagged PDF | Not documented | Built in |
| License | Commercial, fixed license fee by custom quote, Cloud Render billed per use | MIT, free |
When PDFKit is the right call
A fixed-format document generated from data by a backend, with no designer and no end user involved, is exactly what PDFKit is for. Reaching for an editor SDK there adds a license and a dependency to solve a problem you do not have. PDFKit is also the pick when the file itself needs forms, encryption, PDF/A, or tagged PDF/UA output.
If a designer or your users need to change the layout, evaluate Polotno with the 30-day free trial, no credit card needed.
FAQ
Can Polotno generate PDFs without an editor?
Yes. The editor is optional. Build the JSON on your backend and render it through the Cloud Render API or @polotno/pdf-export under Node. See PDF generation.
Is Polotno's output vector like PDFKit's?
Yes, through @polotno/pdf-export. Note that the built-in store.saveAsPDF() is the raster path and flattens each page to an image; pick the vector one for selectable text. The Cloud Render API has a vector mode too.
Can I migrate a PDFKit layout to Polotno?
Not automatically. A PDFKit layout is code, not data. You can import a PDF it produced as a starting point, then rebuild the data-driven parts as a design. That is a good moment to hand the layout to whoever owns it.
What about pdf-lib?
Different job again. pdf-lib edits existing PDFs at the object level. There is a separate comparison for it.
