> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/web/digital-signature/sign-pdf.md).

# Sign a PDF document using JavaScript

Learn how to digitally sign PDF files with the Apryse SDK. Add approval signatures using a Digital Certificate for authenticity and security. Get started now! The Apryse Web SDK streamlines secure, se

{% hint style="info" %}
**Requirements**

*These packages are required to use these features in production. Trial keys have unlimited access to all features*

<a href="https://apryse.com/capabilities#DigitalSignature" class="button primary">Package: Digital Signature</a><a href="https://showcase.apryse.com/digital-signatures" class="button primary">Live demo</a>
{% endhint %}

{% hint style="warning" %}
Make sure you have [Full API enabled in WebViewer.](/web/what-is-webviewer/full-api.md)
{% endhint %}

To sign an existing approval signature field in a PDF Document:

{% tabs %}
{% tab title="JavaScript (SDK v11.12+)" %}
{% code lineNumbers="true" %}

```js
WebViewer({
  fullAPI: true,
  // ...Other config options
}).then(async (instance) => {
  /* This example assumes:
   * - The certificates are hosted from `your-test-env.com/digital-sig/certificate_x.pfx` and `your-test-env.com/digital-sig/cert_x.pem`
   * * - `.pem` files should contain public certificates
   * → used to verify signatures
   *
   * - `.pfx` files contain private key + certificate (PKCS#12 bundle)
   * → used to create digital signatures (requires password)
   */

  const { Annotations, documentViewer } = instance.Core;
  const { VerificationOptions } = instance.UI;
  const annotationManager = documentViewer.getAnnotationManager();
  const fieldManager = annotationManager.getFieldManager();

  // 1. Add trust certificates (PUBLIC certs only)
  VerificationOptions.addTrustedCertificates([
    '/digital-sig/cert_1.pem',
    '/digital-sig/cert_2.pem',
    '/digital-sig/cert_3.pem',
    '/digital-sig/cert_4.pem',
    '/digital-sig/cert_5.pem',
  ]);
  console.log('🔒 Trust certificates added');

  // 2. Listen for signature application events
  annotationManager.addEventListener('digitalSignatureApplied', (details) => {
    console.log('SignatureWidgetInfo From Event: ', details);
  });

  // 3. Create signature fields
  const sigConfigs = [
    { name: 'Sig_1' + Math.random(), page: 1, x: 50, y: 50, w: 200, h: 50 },
    { name: 'Sig_2' + Math.random(), page: 1, x: 300, y: 50, w: 200, h: 50 },
    { name: 'Sig_3' + Math.random(), page: 1, x: 50, y: 120, w: 200, h: 50 },
    { name: 'Sig_4' + Math.random(), page: 1, x: 300, y: 120, w: 200, h: 50 },
    { name: 'Sig_5' + Math.random(), page: 1, x: 50, y: 190, w: 200, h: 50 },
  ];

  const widgets = [];
  for (const cfg of sigConfigs) {
    const field = new Annotations.Forms.Field(cfg.name, { type: 'Sig' });
    fieldManager.addField(field);

    const widget = new Annotations.SignatureWidgetAnnotation(field, {
      appearance: '_DEFAULT',
      appearances: { _DEFAULT: { Normal: { offset: {} } } },
    });
    widget.PageNumber = cfg.page;
    widget.X = cfg.x;
    widget.Y = cfg.y;
    widget.Width = cfg.w;
    widget.Height = cfg.h;
    widgets.push(widget);
  }
  annotationManager.addAnnotations(widgets);
  annotationManager.drawAnnotationsFromList(widgets);
  console.log('📝 Created 5 signature fields');

  // 4. Fetch the cryptographic PFX bundles
  const certs = await Promise.all(
    [1, 2, 3, 4, 5].map(async (i) => {
      const resp = await fetch(`/digital-sig/certificate_${i}.pfx`);
      const buf = await resp.arrayBuffer();
      console.log(`📄 Loaded certificate_${i}.pfx (${buf.byteLength} bytes)`);
      return buf;
    })
  );

  // 5. Apply signatures sequentially
  let signedData;
  for (let i = 0; i < sigConfigs.length; i++) {
    const fieldName = sigConfigs[i].name;
    try {
      console.log(`🖊️ Signing "${fieldName}" with certificate_${i + 1}.pfx...`);
      signedData = await annotationManager.sign(fieldName, {
        certificate: certs[i],
        password: 'test123',
      });
      console.log(`"${fieldName}" signed!`);
    } catch (err) {
      console.error(`Failed to sign "${fieldName}":`, err);
      break;
    }
  }

  console.log('All 5 signatures applied!');

  // 6. Save the signed document
  // sign() resolves to { buffer, fieldName, widget }. Save the buffer —
  // the document open in the viewer is not the signed file.
  const blob = new Blob([signedData.buffer], { type: 'application/pdf' });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = 'signed_doc.pdf';
  link.click();
  URL.revokeObjectURL(url);
});
```

{% endcode %}

[WebViewerInstance](https://sdk.apryse.com/api/web/WebViewerInstance.html)
{% endtab %}

{% tab title="JavaScript (SDK v6.0+)" %}
{% code lineNumbers="true" %}

```js
WebViewer({
  fullAPI: true,
  // ...Other config options
}).then(instance => {
  const { PDFNet, docViewer } = instance;

  docViewer.on('documentLoaded', () => {
    await PDFNet.initialize();
    const doc = await docViewer.getDocument().getPDFDoc();

    // Run PDFNet methods with memory management
    await PDFNet.runWithCleanup(async () => {

      // lock the document before a write operation
      // runWithCleanup will auto unlock when complete
      doc.lock();

      // Add an StdSignatureHandler instance to PDFDoc, making sure to keep track of it using the ID returned.
      const sigHandlerId = await doc.addStdSignatureHandlerFromURL(cert_file_path, 'password');

      // Retrieve the unsigned approval signature field.
      /**
       * Note: Replace approvalFieldName with the field name in the document
       * that is being signed and approved
       */
      const foundApprovalField = await doc.getField(approvalFieldName);
      const approvalSigField = await PDFNet.DigitalSignatureField.createFromField(foundApprovalField);

      // (OPTIONAL) Add more information to the signature dictionary.
      await approvalSigField.setLocation("Vancouver, BC");
      await approvalSigField.setReason("Document approval.");
      await approvalSigField.setContactInfo("www.apryse.com");

      // (OPTIONAL) Add an appearance to the signature field.
      const img = await PDFNet.Image.createFromURL(doc, appearance_img_path);
      const approvalSignatureWidget = await PDFNet.SignatureWidget.createWithDigitalSignatureField(doc, await PDFNet.Rect.init(0, 100, 200, 150), approvalSigField);
      await approvalSignatureWidget.createSignatureAppearance(img);
      const page1 = await doc.getPage(1);
      page1.annotPushBack(approvalSignatureWidget);

      // Prepare the signature and signature handler for signing.
      await approvalSigField.signOnNextSaveWithCustomHandler(sigHandlerId);

      // The actual approval signing will be done during the save operation.
      const buf = await doc.saveMemoryBuffer(0);
      const blob = new Blob([buf], { type: 'application/pdf' });
      saveAs(blob, 'signed_doc.pdf');
    });
  })
})
```

{% endcode %}

[WebViewerInstance](https://sdk.apryse.com/api/web/WebViewerInstance.html) [PDFDoc.createFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#.createFromURL__anchor) [PDFDoc.addStdSignatureHandlerFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#addStdSignatureHandlerFromURL__anchor) [PDFDoc.getField](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getField__anchor) [Field.useSignatureHandler](https://sdk.apryse.com/api/web/Core.PDFNet.Field.html#useSignatureHandler__anchor) [PDFNet.Obj.putName](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putName__anchor) [PDFNet.Obj.putString](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putString__anchor)
{% endtab %}

{% tab title="JavaScript (SDK v8.0+)" %}
{% code lineNumbers="true" %}

```js
WebViewer({
  fullAPI: true,
  // ...Other config options
}).then(instance => {
  const { PDFNet, documentViewer } = instance.Core;

  documentViewer.addEventListener('documentLoaded', () => {
    await PDFNet.initialize();
    const doc = await documentViewer.getDocument().getPDFDoc();

    // Run PDFNet methods with memory management
    await PDFNet.runWithCleanup(async () => {

      // lock the document before a write operation
      // runWithCleanup will auto unlock when complete
      doc.lock();

      // Add an StdSignatureHandler instance to PDFDoc, making sure to keep track of it using the ID returned.
      const sigHandlerId = await doc.addStdSignatureHandlerFromURL(cert_file_path, 'password');

      // Retrieve the unsigned approval signature field.
      /**
       * Note: Replace approvalFieldName with the field name in the document
       * that is being signed and approved
       */
      const foundApprovalField = await doc.getField(approvalFieldName);
      const approvalSigField = await PDFNet.DigitalSignatureField.createFromField(foundApprovalField);

      // (OPTIONAL) Add more information to the signature dictionary.
      await approvalSigField.setLocation("Vancouver, BC");
      await approvalSigField.setReason("Document approval.");
      await approvalSigField.setContactInfo("www.apryse.com");

      // (OPTIONAL) Add an appearance to the signature field.
      const img = await PDFNet.Image.createFromURL(doc, appearance_img_path);
      const approvalSignatureWidget = await PDFNet.SignatureWidget.createWithDigitalSignatureField(doc, await PDFNet.Rect.init(0, 100, 200, 150), approvalSigField);
      await approvalSignatureWidget.createSignatureAppearance(img);
      const page1 = await doc.getPage(1);
      page1.annotPushBack(approvalSignatureWidget);

      // Prepare the signature and signature handler for signing.
      await approvalSigField.signOnNextSaveWithCustomHandler(sigHandlerId);

      // The actual approval signing will be done during the save operation.
      const buf = await doc.saveMemoryBuffer(0);
      const blob = new Blob([buf], { type: 'application/pdf' });
      saveAs(blob, 'signed_doc.pdf');
    });
  })
})
```

{% endcode %}

[WebViewerInstance](https://sdk.apryse.com/api/web/WebViewerInstance.html) [PDFDoc.createFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#.createFromURL__anchor) [PDFDoc.addStdSignatureHandlerFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#addStdSignatureHandlerFromURL__anchor) [PDFDoc.getField](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getField__anchor) [Field.useSignatureHandler](https://sdk.apryse.com/api/web/Core.PDFNet.Field.html#useSignatureHandler__anchor) [PDFNet.Obj.putName](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putName__anchor) [PDFNet.Obj.putString](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putString__anchor)
{% endtab %}
{% endtabs %}

{% hint style="info" %}
**Info**

The signed PDF is in the buffer returned by the signing call. Save or download this buffer, as shown in the code sample above. The document open in the viewer is not the signed file. Downloading the document from the viewer, for example with the Download button or `downloadPdf()`, produces a copy whose signatures fail validation.
{% endhint %}

For more advanced controls - including document permissions, custom signing for HSM integration, and LTV/time stamping - please refer to the sample below: [Digitally sign PDF files](/web/get-started/samples/digitalsignaturestest.md)

## About Adding An Approval Signature to a PDF Document

The Apryse SDK enables approval signatures in PDF documents using a Digital Certificate, in accordance with the latest PDF specification. By leveraging [public key infrastructure (PKI)](https://en.wikipedia.org/wiki/Public_key_infrastructure) technology, with a certificate issued by a trusted [certificate authority (CA)](https://en.wikipedia.org/wiki/Certificate_authority), a signer can use a certificate-based digital ID to guarantee the authenticity of a signature. Placing a digital signature with a certificate can also guarantee that a document has not been modified since the signature was applied, ensuring its authenticity.

![](https://3532544125-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FX9YnTSKIHvV7m0A36LbO%2Fuploads%2Fgit-blob-51c4b698c1ec2efcc0d46686d1342347626f1a9d%2F8130e2be0155c3a56bbf8548f836090a8beb0ac2-299x658.png?alt=media)

Image taken from Apryse WebViewer

Above is an example of a document containing a certified signature, guaranteed by a certificate generated by Apryse.com.


---

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Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.apryse.com/web/digital-signature/sign-pdf.md?ask=<question>&goal=<endgoal>
```

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