Kernstra next to PSPDFKit, Apryse, ComPDF and Syncfusion. PDF SDK pricing, in the open.
Choosing a JavaScript PDF viewer and editor for your web app? Here is how the Kernstra Web SDK is sold and what it does, beside Nutrient (formerly PSPDFKit), Apryse (formerly PDFTron), ComPDF and Syncfusion. Every figure comes from a public page, and each comparison says where the other SDK is the better choice.
How each PDF SDK is priced and sold.
Five questions a buyer asks before the first call. Each column links to the full comparison, where every cell has its source.
| Compared on | Kernstra Web SDKfrom $149 / month, internal app | Nutrient (PSPDFKit) | Apryse (PDFTron) | ComPDF Web SDK | Syncfusion PDF Viewer SDK |
|---|---|---|---|---|---|
| Published price | From $149 a month for an internal app; public-facing apps by quote | Quoted by sales; no price published | Packages from $1,500 a year, then quoted | Starting at $1,300, then quoted | $599 per developer a year |
| Monthly billing, no minimum term | Cancel any month | One year; cannot be monthly | Reported one year or longer | One year at a reseller | One year, payable monthly |
| Priced by | Apps and monthly users; PDFs opened are never counted | Components, deployment mode and users | Base package plus add-ons, per app and platform | Products, features and deployment | Developers, support level, then end users |
| True text editing, in the document's own font | Included in every plan, from $149 a month | Content Editor component | PDF Editing add-on | Content Editor, priced by feature | Not in the viewer |
| Before you pay | Free development key, watermarked | 30-day trial, watermarked | Seven days, then a watermarked trial key | 30-day trial key | 30-day evaluation |
| Kernstra vs Nutrient (PSPDFKit): Full comparison → | Kernstra vs Apryse (PDFTron): Full comparison → | Kernstra vs ComPDF Web SDK: Full comparison → | Kernstra vs Syncfusion PDF Viewer SDK: Full comparison → |
From each vendor's public pages and public pricing data, read on 27 October 2026 (Nutrient's on 10 November 2026); every full comparison links its sources, and we correct anything that turns out wrong. The Nutrient column is its Web SDK license; Nutrient also sells a hosted Viewer API from $199 a month by viewer sessions, a separate service it lists for viewing, annotations, form filling and electronic signatures. Their SDKs do more in places: certificate signing, true redaction, OCR, Office formats, form building, document comparison, real-time collaboration. The full comparisons say where.
One internal app. True text editing and every other tool. As many PDFs as your team opens.
See how pricing scales →Unlimited PDFs
We never count documents, pages or sessions. A user is counted once a month, however many PDFs they open.
True text editing included
Along with annotation, forms, signatures and page tools. Every tool is in the entry price, and a bigger plan never unlocks one.
For internal apps
The entry price is for an internal or back-office app with a limited number of users and a limited development team.
Public-facing apps: by quote
An app your customers or the public use is quoted by its audience. Every tool is still included.
Licensing three or more apps? There is a package for that.They share one subscription at a package price, each on its own domains, on a yearly term.
Ask for package pricingChange the words in a PDF. Included in every plan.
Click a sentence and retype it, in the document's own font, with the paragraph reflowing around it. Not a white box over the old words. Other SDKs sell it as an add-on or a separate component, or leave it out of the viewer. In Kernstra it comes with every plan, from $149 a month.
How each SDK sells text editing
- Kernstra Web SDKIncluded in every plan
- Nutrient (PSPDFKit)Content Editor component
- Apryse (PDFTron)PDF Editing add-on
- ComPDF Web SDKContent Editor, priced by feature
- Syncfusion PDF Viewer SDKNot in the viewer
Kernstra as an alternative to each: first-year cost, features, and when to choose them.
- Nutrient Web SDK · formerly PSPDFKit
Only one publishes its SDK price.
PSPDFKit alternative: Kernstra vs Nutrient →Quote on requestNo published price: scoped and quoted by sales$149 / monthInternal app, true text editing included - Apryse WebViewer · formerly PDFTron
Only one publishes a monthly price.
Apryse (PDFTron) alternative: Kernstra vs Apryse →Quote on requestCustom pricing; packages from $1,500 a year$149 / monthInternal app, true text editing included - ComPDF Web SDK · formerly ComPDFKit
Only one puts every tool in the price.
ComPDF alternative: Kernstra vs ComPDF →Quote on requestFrom $1,300 for simple use cases, says ComPDF$149 / monthInternal app, true text editing included - Syncfusion PDF Viewer SDK
One is priced per developer, the other per app.
Syncfusion PDF Viewer alternative: Kernstra vs Syncfusion →$599 / dev / yearPublished, with a price calculator$149 / monthInternal app, true text editing included
A comparison you can check, line by line.
Public sources only
Each figure comes from the vendor's own pages or public pricing data, and every comparison lists its sources at the foot of the page.
Dated
Prices change. Each page states the day its sources were read, so you know how fresh a figure is before you rely on it.
The rows we lose are in
Every feature table keeps the rows where the other SDK does more, and every page says when it is the better choice.
Corrected when wrong
If a vendor changes a price or we got something wrong, write to us and we correct the page.
Before you shortlist.
Anything else, ask in the quote form and an engineer answers in writing.
Ask in the quote formIs there a PSPDFKit alternative with a published price?
Yes. PSPDFKit is now Nutrient, and its Web SDK license is quoted by sales. The Kernstra Web SDK publishes its price: from $149 a month for an internal app, billed monthly, with every tool included. Kernstra vs Nutrient Web SDK sets the two side by side.
Which PDF SDK includes text editing in its base price?
Kernstra does: true text editing, in the document's own font, is in every plan from $149 a month. Nutrient sells its Content Editor as a separate component, Apryse sells PDF Editing as an add-on, ComPDF prices its Content Editor by feature, and Syncfusion's own FAQ says changing existing text typically needs other tools. You can try it on your own PDF in the playground.
How much does a PDF SDK cost?
It depends on how it is sold. Syncfusion publishes $599 per developer a year. Apryse publishes packages from $1,500 a year and quotes above that, ComPDF states a starting figure of $1,300, and Nutrient quotes. Kernstra starts at $149 a month for an internal app.
What does $149 a month include, and do you count PDFs?
One internal or back-office app with a limited number of users, billed monthly, with every tool. We do not count PDFs: a user is one browser that loads the SDK in the billing month, counted once however many documents, pages or sessions it opens. Public-facing apps are priced by quote, by apps and monthly users, and three or more apps get package pricing. The pricing page has the detail.
When is another SDK the better choice?
When you need something Kernstra does not do today, such as certificate signing, true redaction, OCR, Office formats, form building, document comparison or real-time collaboration. Each comparison lists those rows.
Build it this afternoon. Decide about a plan when there is something to ship.
Development keys are free and watermarked. No call, no quote.