Apache PDFBox is a widely used open-source Java library maintained by the Apache Software Foundation. It covers text extraction, form filling, PDF creation, and digital signatures. The main constraints are JVM startup overhead, minimal XFA support, and no WASM target. PDFluent is a native Rust library with a WASM package (@pdfluent/sdk-wasm 1.0.0: 3.8 MB Brotli-compressed, measured 2026-09-16).
use pdfluent::PdfDocument;
fn main() -> pdfluent::Result<()> {
let mut doc = PdfDocument::open("contract.pdf")?;
// Extract text
let text = doc.page(1)?.text()?;
println!("{}", text);
// Fill an AcroForm field, then flatten
doc.form_mut().set_text("signature_date", "2024-04-14")?;
doc.flatten_forms()?;
doc.save("contract_signed.pdf")?;
Ok(())
}import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
public class Example {
public static void main(String[] args) throws Exception {
PDDocument doc = PDDocument.load(new File("contract.pdf"));
// Extract text
PDFTextStripper stripper = new PDFTextStripper();
String text = stripper.getText(doc);
System.out.println(text);
// Fill AcroForm field
PDAcroForm acroForm = doc.getDocumentCatalog().getAcroForm();
acroForm.getField("signature_date").setValue("2024-04-14");
acroForm.flatten();
doc.save("contract_signed.pdf");
doc.close();
}
}| Feature | PDFluent | Apache PDFBox |
|---|---|---|
| Language / runtime | Rust, no runtime | Java / JVM required |
| Cold start | No runtime to start; opening a file: 1.7 ms median on one MacBook (A22, 2026-08-24) | JVM startup on every cold invocation |
| Memory baseline | No JVM | Requires a JVM |
| WASM / browser support | ||
| XFA forms | Limited | |
| PDF/A validation | Partial | |
| Digital signatures (PAdES) | ||
| License | AGPLv3 or commercial | Apache 2.0 (free) |
PDFluent fits serverless environments, or anywhere a JVM cold start or memory overhead is a problem. Also choose PDFluent if you need XFA support or digital signatures.
Apache PDFBox is a reasonable choice if you already have a Java stack, cost is a constraint (it's free), and throughput requirements are moderate. For basic PDF reading and text extraction in a Java service, PDFBox works well.
PDFBox is a solid choice for JVM-based applications that do not need XFA, WASM, or cold starts without a JVM. It is free and well documented. If your stack is already Java, it works. If you are starting new, need serverless, or need XFA support, PDFluent is a better fit.
Free under the AGPLv3, or a commercial licence if you would rather not publish your own source.