Getting Started

Kura can be used in a few different ways, but the engine underneath is always the same. Whichever surface you pick, you get the same 25 targets, the same preflight profiles, the same options, and the same JSON report from the same settings.

The fastest way: your browser

If you just want to convert or check a PDF, you do not need to install anything.

1. Open kura.bentopdf.com.
2. Drop your PDF onto the page, or click to choose it.
3. Pick a target, PDF/A-2b for most archival work, and press Convert. Or turn on "Check only" to see what would change without producing a file.
4. Save the result.

The engine runs as WebAssembly inside your browser. Your file is never uploaded anywhere; load the page, disconnect from the internet, and it still works.

From the terminal

With npm

npm install -g kura-pdf
kura --level 2b input.pdf output.pdf

kura-pdf installs the native engine through a platform package for Linux x64, macOS arm64 or Windows x64; the kura command is the native CLI itself. On any other platform, npm install -g kura-pdf-wasm gives the kura-wasm command with the same flags on the WebAssembly build.

With the native binary

Prebuilt binaries for Linux, Windows and macOS are attached to every release. They are single files with no dependencies beyond the operating system, and they are faster than the npm build and add --sign, --ocr and a few other features that need the host. Download the archive for your platform, verify it against SHA256SUMS, and put kura on your PATH.

Common variations, identical on both:

kura --level 2a --ua in.pdf out.pdf          # archival plus accessibility
kura --level x1a in.pdf out.pdf              # CMYK print
kura --check --level 2b in.pdf               # report only, write nothing
kura --einvoice invoice.xml in.pdf out.pdf   # hybrid e-invoice
kura --password hunter2 --level 2b in.pdf out.pdf
kura --level 2b -r -d out/ inbox/            # a whole folder

Every flag is documented on the CLI page.

From Node.js code

import { readFile, writeFile } from 'node:fs/promises';
import { convert } from 'kura-pdf';

const input = new Uint8Array(await readFile('input.pdf'));
const result = await convert(input, '2b', { ua: false });

await writeFile('output.pdf', result.pdf);
for (const issue of result.issues) console.log(issue.code, issue.detail);

Save that as convert.mjs next to an input.pdf and run node convert.mjs. The npm page walks through check(), error handling, e-invoices and running the engine in a worker.

In a container

docker run -d -p 8080:8080 ghcr.io/alam00000/bentopdf-kura:latest

That serves the web interface at http://localhost:8080 and an HTTP API on the native engine, all on your own machine. The same image is the CLI when you pass arguments:

docker run --rm --user "$(id -u):$(id -g)" -v "$PWD:/work" \
  ghcr.io/alam00000/bentopdf-kura:latest --level 2b in.pdf out.pdf

Self-hosting covers configuration, TLS, updates and monitoring.

Picking a target

Most people want one of three:

You want	Use
a document that will still open and read correctly in decades	2b
the same, plus text that is guaranteed searchable and copyable	2u
the same, plus accessibility for screen readers	2a --ua

Add 3b, 3u or 3a instead when the document must carry attachments, and 4 when you want the current PDF 2.0-based standard. Print, engineering and variable-data work use the PDF/X, PDF/E and PDF/VT families. The standards page explains every target and when to choose it.

Three things to know before you start

1. The output conforms or you get an error. Kura never writes a file that claims a standard it does not meet. A rejection carries an error code and, where one exists, a suggestedLevel that would work; TRANSPARENCY_P1 on a PDF/A-1 job, for instance, suggests 2b.
2. Every change is in the report. The issues list is complete: fonts substituted, colour converted, pages rasterized, content removed. Nothing happens silently.
3. Check mode is a preflight, not a validator. --check reports exactly what the converter would repair, so it never gives a false finding, but it cannot see defects the converter does not know how to fix. Use an independent validator for certification.

Where next

• Every flag and exit code: CLI
• The programming interface: npm package and C API
• What each target means: The standards
• Every error code and what to do: Rejection codes
• Factur-X, ZUGFeRD, XRechnung, Order-X: E-invoices
• Print and archival rules of your own: Preflight profiles