Document Generation & PDF Automation

Expert in generating, filling, and assembling PDF documents programmatically for legal, HR, and business workflows.

When to Use

✅ Use for:

Legal form automation (expungement, immigration, contracts) Invoice/receipt generation at scale Certificate creation (completion, participation, awards) Contract assembly from templates Government form filling (IRS, court filings) Multi-document packet creation

❌ NOT for:

Simple PDF viewing (use browser or pdf.js) Basic file conversion (use online tools) OCR text extraction (use Tesseract.js or AWS Textract) PDF editing by hand (use Adobe Acrobat) Technology Selection pdf-lib vs Puppeteer vs LaTeX Feature pdf-lib Puppeteer LaTeX Form filling ✅ Native ❌ Complex ❌ No Template rendering ❌ No ✅ HTML/CSS ✅ Templates Performance (1000 PDFs) 5s 60s 30s File size Small Medium Small Signature fields ✅ Yes ❌ No ❌ No Best for Government forms Invoices, reports Academic papers

Timeline:

2000s: LaTeX for academic documents 2010: PDFKit (Node.js) for generation 2017: Puppeteer for HTML → PDF 2019: pdf-lib for pure JS form filling 2024: pdf-lib is gold standard for forms

Decision tree:

Need to fill existing form? → pdf-lib Need complex layouts? → Puppeteer (HTML/CSS) Need academic formatting? → LaTeX Need to merge PDFs? → pdf-lib Need digital signatures? → pdf-lib + DocuSign API

Common Anti-Patterns Anti-Pattern 1: Using Puppeteer for Simple Form Filling

Novice thinking: "I'll use Puppeteer for everything, it's versatile"

Problem: 12x slower, 10x more memory, can't preserve form fields.

Wrong approach:

// ❌ Puppeteer for simple form filling (SLOW!) import puppeteer from 'puppeteer';

async function fillForm(data: FormData): Promise { const browser = await puppeteer.launch(); const page = await browser.newPage();

// Load PDF in browser await page.goto(file://${pdfPath});

// Somehow fill form fields? (hacky) await page.evaluate((data) => { // Can't easily access PDF form fields from DOM // Would need to convert PDF → HTML first }, data);

const pdf = await page.pdf(); await browser.close();

return pdf; }

Why wrong:

Browser overhead (200MB+ RAM per instance) Can't access native PDF form fields Loses interactive form capabilities 12x slower than pdf-lib

Correct approach:

// ✅ pdf-lib for form filling (FAST!) import { PDFDocument } from 'pdf-lib';

async function fillForm(templatePath: string, data: FormData): Promise { // Load existing PDF form const existingPdfBytes = await fs.readFile(templatePath); const pdfDoc = await PDFDocument.load(existingPdfBytes);

// Get form const form = pdfDoc.getForm();

// Fill text fields form.getTextField('applicant_name').setText(data.name); form.getTextField('case_number').setText(data.caseNumber); form.getTextField('date_of_birth').setText(data.dob);

// Fill checkboxes if (data.hasPriorConvictions) { form.getCheckBox('prior_convictions').check(); }

// Fill dropdowns form.getDropdown('state').select(data.state);

// Flatten form (make non-editable) form.flatten();

// Save return await pdfDoc.save(); }

Performance comparison (1000 PDFs):

Puppeteer: 60 seconds, 4GB RAM pdf-lib: 5 seconds, 200MB RAM

Timeline context:

2017: Puppeteer released, everyone used it for PDFs 2019: pdf-lib released, proper form handling 2024: pdf-lib is standard for government forms Anti-Pattern 2: Not Flattening Forms

Problem: Users can edit filled forms, causing data inconsistencies.

Wrong approach:

// ❌ Don't flatten - form stays editable const pdfDoc = await PDFDocument.load(existingPdfBytes); const form = pdfDoc.getForm();

form.getTextField('name').setText('John Doe');

const pdfBytes = await pdfDoc.save(); // User can open PDF and change "John Doe" to anything!

Why wrong:

User can modify official documents Data doesn't match database Violates document integrity

Correct approach:

// ✅ Flatten form after filling const pdfDoc = await PDFDocument.load(existingPdfBytes); const form = pdfDoc.getForm();

form.getTextField('name').setText('John Doe');

// Flatten (convert fields to static text) form.flatten();

const pdfBytes = await pdfDoc.save(); // User can't edit filled values ✅

When NOT to flatten:

Draft documents (user needs to review/edit) Multi-step workflows (partial completion) Templates for users to fill manually Anti-Pattern 3: Generating PDFs from HTML Without Page Breaks

Novice thinking: "HTML → PDF is easy with Puppeteer"

Problem: Content splits mid-sentence across pages.

Wrong approach:

// ❌ No page break control const html = `

`;

const pdf = await page.pdf({ format: 'A4' }); // Result: Ugly page breaks in middle of sections

Correct approach:

// ✅ Explicit page break control with CSS const html = `
<style> @media print { .page-break { page-break-after: always; } .avoid-break { page-break-inside: avoid; } h1, h2, h3 { page-break-after: avoid; page-break-inside: avoid; } section { page-break-inside: avoid; } } </style>

`;

const pdf = await page.pdf({ format: 'A4', printBackground: true, margin: { top: '1in', right: '1in', bottom: '1in', left: '1in' } });

CSS print properties:

page-break-before: always - Force new page before element page-break-after: always - Force new page after element page-break-inside: avoid - Keep element together Anti-Pattern 4: Not Handling Signature Fields

Problem: Signature fields aren't clickable in generated PDFs.

Wrong approach:

// ❌ Add signature as image (not a real signature field) const pdfDoc = await PDFDocument.load(existingPdfBytes);

const signatureImage = await pdfDoc.embedPng(signaturePngBytes); const page = pdfDoc.getPage(0);

page.drawImage(signatureImage, { x: 100, y: 100, width: 200, height: 50 });

await pdfDoc.save(); // Not a real signature field - can't be signed digitally

Why wrong:

Not legally recognized (just an image) Can't use DocuSign/Adobe Sign No signature metadata (who, when)

Correct approach 1: Create signature field (for DocuSign)

// ✅ Create signature field for electronic signing const pdfDoc = await PDFDocument.load(existingPdfBytes); const form = pdfDoc.getForm();

// Create signature field const signatureField = form.createTextField('applicant_signature'); signatureField.addToPage(pdfDoc.getPage(0), { x: 100, y: 100, width: 200, height: 50 });

// Mark as signature field (metadata) signatureField.updateWidgets({ borderWidth: 1, borderColor: { type: 'RGB', red: 0, green: 0, blue: 0 } });

await pdfDoc.save(); // DocuSign can now detect and fill this field ✅

Correct approach 2: DocuSign API integration

// ✅ Send to DocuSign for e-signature import { ApiClient, EnvelopesApi } from 'docusign-esign';

async function sendForSignature(pdfBytes: Uint8Array, signerEmail: string) { const apiClient = new ApiClient(); apiClient.setBasePath('https://demo.docusign.net/restapi');

const envelopesApi = new EnvelopesApi(apiClient);

const envelope = { emailSubject: 'Please sign: Expungement Petition', documents: [{ documentBase64: Buffer.from(pdfBytes).toString('base64'), name: 'Petition.pdf', fileExtension: 'pdf', documentId: '1' }], recipients: { signers: [{ email: signerEmail, name: 'John Doe', recipientId: '1', tabs: { signHereTabs: [{ documentId: '1', pageNumber: '1', xPosition: '100', yPosition: '100' }] } }] }, status: 'sent' };

return await envelopesApi.createEnvelope(accountId, { envelopeDefinition: envelope }); }

Anti-Pattern 5: Storing Filled PDFs Without Encryption

Problem: Sensitive legal documents stored in plain text.

Wrong approach:

// ❌ Save PDF to disk unencrypted const pdfBytes = await pdfDoc.save(); await fs.writeFile(./documents/${caseId}.pdf, pdfBytes); // Sensitive data accessible to anyone with file system access

Why wrong:

Legal/medical data exposed HIPAA/GDPR violations Data breach liability

Correct approach 1: Encrypt at rest

// ✅ Encrypt PDF with user password const pdfBytes = await pdfDoc.save({ userPassword: generateSecurePassword(), ownerPassword: process.env.PDF_OWNER_PASSWORD, permissions: { printing: 'highResolution', modifying: false, copying: false, annotating: false, fillingForms: false, contentAccessibility: true, documentAssembly: false } });

await fs.writeFile(./documents/${caseId}.pdf, pdfBytes);

Correct approach 2: Store in encrypted storage (S3 with SSE)

// ✅ Upload to S3 with server-side encryption import { S3Client, PutObjectCommand } from '@aws-sdk/client-s3';

const s3Client = new S3Client({ region: 'us-east-1' });

await s3Client.send(new PutObjectCommand({ Bucket: 'expungement-documents', Key: cases/${caseId}/petition.pdf, Body: pdfBytes, ServerSideEncryption: 'AES256', Metadata: { caseId: caseId, documentType: 'petition', generatedAt: new Date().toISOString() }, ACL: 'private' // Not publicly accessible }));

// Store S3 URL in database (encrypted) await db.documents.insert({ case_id: caseId, s3_url: encrypt(s3://expungement-documents/cases/${caseId}/petition.pdf), created_at: new Date() });

Compliance requirements:

HIPAA: Encryption at rest + in transit, access logging GDPR: Right to deletion, data minimization State bar rules: Attorney-client privilege protection Production Checklist □ Form fields filled correctly (test with validation) □ Forms flattened after filling (non-editable) □ Page breaks controlled (no mid-sentence splits) □ Signature fields created (for DocuSign/Adobe Sign) □ PDFs encrypted at rest (S3 SSE or user password) □ Access logged (who viewed/downloaded) □ Auto-deletion scheduled (retention policy) □ Fonts embedded (cross-platform compatibility) □ File size optimized (<5MB per document) □ Batch generation tested (1000+ PDFs)

When to Use vs Avoid Scenario Appropriate? Fill 50+ government forms ✅ Yes - automate with pdf-lib Generate invoices from template ✅ Yes - Puppeteer from HTML Create certificates at scale ✅ Yes - pdf-lib or LaTeX Assemble multi-doc packets ✅ Yes - pdf-lib merge View PDFs in browser ❌ No - use pdf.js or browser Edit PDF by hand ❌ No - use Adobe Acrobat Extract text with OCR ❌ No - use Tesseract/Textract References /references/pdf-lib-guide.md - Form filling, field types, flattening, encryption /references/puppeteer-templates.md - HTML templates, page breaks, styling for print /references/document-assembly.md - Merging PDFs, packet creation, watermarks Scripts scripts/form_filler.ts - Fill PDF forms from JSON data, batch processing scripts/document_assembler.ts - Merge multiple PDFs, add cover pages, watermarks

This skill guides: PDF generation | Form filling | Document automation | Digital signatures | pdf-lib | Puppeteer | LaTeX | DocuSign