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Compare · Kernstra vs Apryse WebViewer, formerly PDFTron

Apryse, once PDFTron, and Kernstra both put a PDF editor in your web app. Only one publishes a monthly price.

Apryse WebViewer, formerly PDFTron WebViewer, is a deep and mature web SDK sold the enterprise way: a custom quote, a base package, and add-on modules for editing, signing and conversion. The Kernstra Web SDK starts at $149 a month for an internal or back-office app, billed monthly if you like, with every tool included at that price. This page sets the two side by side, including where Apryse WebViewer is the better choice.

See the first-year costCompare the features
Kernstra Web SDK
$149/ month
  • Published on the pricing page
  • Monthly billing, no minimum term
  • All twenty-six tools at the $149 entry price
  • Free development key, watermarked
Apryse WebViewer
Quoteon request
  • Custom pricing; packages from $1,500 a year
  • Yearly contracts, one to three years as buyers report
  • Base package, then add-on modules
  • Trial key, every document watermarked
First-year cost

Apryse pricing next to Kernstra: what a team pays in year one.

Kernstra's entry plan, twelve months at the published price, next to what buyers report paying Apryse. The bars share one scale.

Kernstraentry plan · 12 × $149
$1,788
Aprysepublished entry package
$1,500
ApryseVendr low
$6,556
ApryseVendr median
$24,351
ApryseVendr high
$108,539
14×Vendr's median, across Apryse's SDKs, is about fourteen times a year of Kernstra's entry plan, with true text editing included and no yearly contract.
$149a month, and true text editing is in it: no PDF Editing add-on, no annual contract, stop after any month. Bigger use gets a price within one business day.
$0to build the whole integration first. Development keys are free, never counted, watermarked and never expire.

Kernstra: the published $149 entry price for an internal or back-office app with a limited number of users, billed monthly; public-facing apps and larger use are priced to their use, and yearly billing includes two months free. Apryse: every figure comes from the public sources listed below, chiefly Vendr marketplace data from 45 Apryse purchases, last updated July 2026, which is for Apryse as a whole, not broken down by SDK. Vendr adds that discounts of 15–30% off initial quotes are common. Apryse itself publishes only that packages start from $1,500 a year, so your quote may differ. Sources

How you buy it

A price you can read today, or a quote after a sales call.

For a startup or a SaaS team with a document feature on the roadmap, how the license is sold matters as much as the number on it.

KernstraApryse WebViewer
PriceFrom $149 a month, publishedNot published beyond the entry point; custom-quoted
Entry point$149 a month for an internal or back-office app, or $1,490 a year on yearly billingPackages from $1,500 a year; most reported deals are higher
BillingMonthly, quarterly or yearly (two months free)Annual; buyers report one- to three-year terms
Minimum termNone on monthly billingNot published; reported terms are one year or longer
What you licenseThe whole SDK: twenty-six tools and the full API at the $149 entry priceA base package, then add-ons such as PDF editing, digital signatures, DOCX and spreadsheet editors, conversion and data extraction
What sets the priceWho uses the app (internal or public-facing), your users and your apps; never below $149Modules, use case, document volume, client- or server-side; licensed per application and per platform
Before you payFree development key, watermarked, never expiresSeven days without a key, then a free trial key; documents watermarked
Time to a priceWritten quote in one business day, or read the entry price on the pageQuote form; a specialist replies within one business day
What the SDK does

Apryse vs Kernstra, feature by feature, including the rows we lose.

Apryse WebViewer covers more ground than Kernstra does today. If a row marked for Apryse WebViewer is a requirement, that should decide it.

IncludedPartly, or as a paid add-onNot available
KernstraApryse WebViewer
Viewing and editing
Renders in the browser, no server neededAlwaysWebAssembly; WebViewer Server optional
Edit existing text in the document's own fontIncluded at the $149 entry pricePDF Editing add-on
Large files open before the download finishesPage streaming: a 107 MB file opens after about 0.2 MBLinearized PDFs
Phone, tablet and desktop layouts from one configMeasured from the containerResponsive UI
React, Vue, Angular, Svelte, Next.js, NuxtAlso SvelteKitAlso Electron and Blazor
Accessible viewer interface (WCAG)Accessible text layer and ARIA page regions, designed for a WCAG 2.1 review; audit report to followApryse states WCAG 2.2 AA for the UI
Compare two versions of a documentCompare package: overlay, side-by-side and text compare
Annotation, forms and signing
Highlights, notes, drawing, shapes, stampsIncluded at the $149 entry priceBase package
Fill existing PDF formsIncluded at the $149 entry priceBase package
Create form fields (form designer)Coming nextWith the Digital Signatures add-on
Drawn, typed or uploaded signaturesIncluded at the $149 entry priceDigital Signature package
Certificate-based digital signatures (PKI)Lists existing ones; does not create or verify themDigital Signatures add-on
Threaded comment replies and review statusComments panel, written as Acrobat writes themNotes panel
Real-time collaborationWith a sync server you build
Security and processing
Documents never sent to the vendorNothing from a document leaves the browserIn the client-side deployment
Password protection and permissionsIncluded at the $149 entry priceSecurity package, with the Full API
True redaction (content removed from the file)Black-out covers, it does not removeRedaction module
OCR for scanned pagesWith the Server SDK, licensed separately
Office and CAD files in the viewerConversion add-on; CAD needs a server
SOC 2 Type 2 reportNot yet

The Apryse WebViewer column comes from the public Apryse pages and Vendr data listed under Sources; "add-on" or "module" means it is licensed separately and priced into the quote. Checked 27 October 2026. Sources

Which one to choose

When Kernstra is the better Apryse (PDFTron) alternative, and when it is not.

Choose Kernstra if

  • You want to ship before you sign a contract. Build on a free key, go live on a monthly plan, and stop any month.
  • Your budget is a line on a company card, not a procurement cycle. For an internal or back-office app, $149 a month is a decision one person can make.
  • You need true text editing without an add-on. Editing in the original font, annotation, form filling and signing are all included at the $149 entry price.
  • Documents must never leave the browser, with nothing for you to host: the SDK makes a license status check on each load and downloads its engine and fonts, none of it carrying a document's content, and there is no telemetry.

Choose Apryse WebViewer if

  • Your users work in Word, Excel or CAD files and need to view or edit them in the browser alongside PDFs.
  • You need certificate-based digital signatures or form building today, or true redaction for regulated disclosure.
  • You process scans, compare versions or measure drawings and want OCR, data extraction, comparison and measurement from the same vendor.
  • Your procurement requires SOC 2, ISO 27001 or a WCAG 2.2 AA claim and a yearly enterprise agreement is the norm for you.
Switching from Apryse WebViewer

Switching from Apryse WebViewer to Kernstra.

Both SDKs mount into one element and take a document and a configuration object, so the shape of your code stays the same.

  1. 1
    Take a free development keyRun Kernstra beside your current viewer on localhost or any HTTPS host while you compare, watermarked, with no expiry.
  2. 2
    Swap the mount callAfter Kernstra.init() and PDFDocument.fromUrl(), new PDFViewer(container, doc, config) replaces the WebViewer() call; the container and document URL carry over, and your toolbar choices become tools and toolbar settings.
  3. 3
    Map your eventsPage, form-field, annotation, signature and export events have counterparts in the SDK API reference: pageChanged, formFieldChanged, annotationsChanged, signatureCaptured and exportCompleted.
  4. 4
    Go live monthlyMove to a production key when you are ready. Your Apryse term can run out while you are already live.
Questions

Questions before you switch from Apryse or sign.

Anything else, ask in the quote form and an engineer answers in writing.

Ask in the quote form

Is Apryse the same company as PDFTron?

Yes. PDFTron renamed itself Apryse in February 2023. WebViewer is the same web SDK, and its npm package is still published as @pdftron/webviewer (version 12.2.1 in October 2026).

How much does Apryse WebViewer (PDFTron) cost, and where do these prices come from?

From the public sources listed at the foot of this page. Apryse does not publish WebViewer prices; it says entry packages start from $1,500 a year. The other figures are Vendr's marketplace data from 45 Apryse purchases, last updated July 2026: a median of $24,351 a year, with a low of $6,556 and a high of $108,539 as Vendr states them. They are for Apryse as a whole, not broken down by SDK, and your quote depends on the modules and volume you need. If a figure is wrong or out of date, tell us and we will correct it.

Is $149 really the price, or a teaser?

It is the published entry price for an internal or back-office app with a limited number of users, billed monthly, and it includes every tool, Edit Text and Add Text among them. A public-facing app or larger use gets a package priced to its use, never below $149, quoted within one business day. Billing is monthly with no minimum term, quarterly, or yearly with two months free ($1,490 a year).

Does Kernstra do everything Apryse WebViewer does?

No, and the feature table says where. Office and CAD files, certificate-based signing, form building, true redaction, OCR, document comparison, measurement and real-time collaboration are available from Apryse (OCR and CAD through its Server SDK), not in Kernstra today; form building and measurement are the next tools we are working on.

Can we try both side by side?

Yes. Apryse WebViewer runs for seven days without a key and then on a free trial key that watermarks every document; a Kernstra development key is free, watermarked and never expires, so you can run both on the same page of your app and decide on your own schedule.

Start where the price is

Build it this afternoon. Decide about a plan when there is something to ship.

A free development key, the whole SDK, and a published price you can check without a call.

Start freeSee pricing

Sources, checked 27 October 2026

Apryse WebViewer and PDFTron are trademarks of their owner. Every figure and claim about Apryse WebViewer on this page comes from the public sources listed here, read on 27 October 2026. If anything is wrong or out of date, tell us at hello@kernstra.com and we will correct it.

  1. vendr.comJuly 2026Apryse Software Pricing & Plans 2026 (Vendr)

    Median $24,351 a year from 45 purchases, with a low of $6,556 and a high of $108,539 as Vendr states them; for Apryse as a whole, not broken down by SDK; discounts of 15–30% off initial quotes are common; a base package plus à la carte modules such as OCR/ICR, redaction, digital signatures and conversion; terms commonly one to three years.

  2. apryse.comApryse Pricing and Licensing

    Custom, modular pricing set by features, document volume and client- or server-side use; entry packages from $1,500; base package (viewer, annotations, linearization, form filling, measurement, WCAG 2.2 AA UI); form building only with the Digital Signing add-on; add-ons DOCX Editor, Spreadsheet Editor, Digital Signatures, Smart Data Extraction, PDF Editing and Conversion (30+ formats); a specialist replies to the quote form within one business day.

  3. apryse.comApryse SDK Pricing Guide

    Entry packages "as low as $1500 a year"; modular components such as viewing, annotation, secure redaction and data extraction; price set by the application and its intended use.

  4. apryse.comWebViewer: JavaScript Document SDK for PDF, Office & CAD

    Client-side WebAssembly, document content never leaves the browser; 30+ formats including Office and CAD; React, Angular, Vue, Nuxt, Next.js, Svelte, Electron and Blazor; linearization; text editing; redaction; overlay, side-by-side and semantic text comparison; measurement; ISO 27001 and SOC 2.

  5. docs.apryse.comOverview of the WebViewer JavaScript PDF and DOCX Library

    Renders in the browser with WebAssembly; WebViewer Server is an optional backend; CAD documents load through WebViewer Server.

  6. docs.apryse.comEdit text and images in PDFs using the WebViewer JavaScript library

    Content editing is a separate add-on, not included in a standard WebViewer license.

  7. docs.apryse.comWhy do I see watermark when I enter a valid license key?

    Apryse licenses per application and per platform; keys carry an expiry date.

  8. docs.apryse.comAdd a License Key to WebViewer

    A watermark shows until a valid key is entered; a commercial key is required in production.

  9. cdn.jsdelivr.net@pdftron/webviewer 12.2.1, README

    A 7-day trial with no trial key needed, extended with a trial key from the developer portal; responsive UI; framework guides.

  10. registry.npmjs.org16 October 2026@pdftron/webviewer on the npm registry

    Still published under the @pdftron name; latest version 12.2.1.

  11. docs.apryse.com1 October 2026Apryse Web SDK release notes

    The latest WebViewer release listed is v12.2.0.

  12. community.apryse.com27 March 2025Know how to access the webviewer all the time without being in a 7-day free trial (Apryse Community)

    Apryse staff: a demo license key gives an unlimited trial; all documents loaded or generated are watermarked.

  13. docs.apryse.comUse the digital signature tool in WebViewer

    Ink, typed and uploaded signatures; the Digital Signature package is required in production.

  14. sdk.apryse.comApryse WebViewer Namespace: NotesPanel

    Comment threads with replies, and review statuses (Accepted, Rejected, Cancelled, Completed and others).

  15. docs.apryse.comLearn More About Document Collaboration in WebViewer

    "Apryse does not ship any server side collaboration tools"; you implement the sync flow yourself.

  16. docs.apryse.comApplying redactions to PDFs

    Redacted content is destroyed, not hidden; applying redactions, even programmatically, needs the Full API or WebViewer Server.

  17. community.apryse.com27 November 2025How to access OCR module in webviewer (Apryse Community)

    Apryse staff: the OCR module is not available in WebViewer and runs with the Server SDK.

  18. docs.apryse.comCompare PDF File Differences with JavaScript

    PDF overlay, pixel-by-pixel image overlay and semantic text comparison; the Compare package is required in production.

  19. docs.apryse.comEncrypting & securing PDFs using JavaScript

    User passwords and permissions; the Security package is required in production, with the Full API enabled.

  20. docs.apryse.comAccessibility for the WebViewer JavaScript PDF Viewer

    WebViewer 11.6 achieved WCAG 2.2 AA for the UI (Apryse's statement); no VPAT or conformance report is linked.

  21. apryse.comSecurity and Compliance | Apryse

    ISO/IEC 27001:2022 certified (certifications held since 2018); yearly SOC 2 Type II audits.

  22. apryse.com8 February 2023PDFTron Rebrands as Apryse

    PDFTron Systems Inc. rebranded under the name Apryse.