Toolvana: production-ready media tools platform (CodeIgniter 4)

- 134-tool registry with programmatic SEO (unique titles/H1/descriptions,
  JSON-LD graphs, sitemap index, canonical 301 enforcement via required filter)
- DB-backed job queue (SKIP LOCKED) with drivers: Ffmpeg, Images (GD),
  Pdf (qpdf/gs/poppler), Youtube (thumbnails), Qr (server-side PNG)
- Security: SSRF guard, MIME validation, rate limits, API-key auth,
  bcrypt admin login, security headers
- Admin panel: dashboard, tools/categories/guides CRUD, SEO audit,
  analytics, job inspector with retry, system health, feature flags
- Docker deployment (nginx + web/api FPM pools + scalable workers),
  PHPUnit suite (19 tests / 1139 assertions), PWA manifest + service worker

content/guides/how-to-merge-pdf-files.md

@@ -0,0 +1,51 @@
+---
+slug: how-to-merge-pdf-files
+title: "How to Merge PDF Files Into One Document"
+excerpt: "Combine scans, contracts and statements into a single ordered PDF — plus page-order tricks and privacy notes."
+seo_title: "How to Merge PDF Files Online – Free & Private"
+seo_description: "Merge multiple PDF files into one document online for free. Reorder pages, keep quality, and learn how private the process really is."
+date: "2025-12-18"
+tools: ["pdf-merger", "pdf-splitter", "pdf-page-extractor"]
+---
+
+Merging PDFs is the most common document chore there is: scanned pages that arrived separately, a contract split across three emails, statements needing one combined archive. Here is the fast path.
+
+## Merging in four steps
+
+1. Open the [PDF Merger](/pdf-merger).
+2. Upload your first file — then add the rest; upload order becomes page order.
+3. Press Merge.
+4. Download the combined document.
+
+Files are stitched with qpdf, a battle-tested open-source engine. Output keeps original page quality — no re-compression unless you ask for it separately.
+
+## Getting page order right
+
+The most common mistake: uploading files alphabetically when the intended order differs. Two fixes:
+
+- **Rename before uploading** (`01-scan.pdf`, `02-scan.pdf` ...).
+- Or merge first, then reorder by extracting page ranges with the [PDF Page Extractor](/pdf-page-extractor) and re-merging.
+
+## When to split instead of merge
+
+Sometimes the opposite job is needed. The [PDF Splitter](/pdf-splitter) breaks a document into single-page files (zipped), which suits:
+
+- Distributing individual chapters
+- Pulling one signed page from a packet
+
+## Privacy notes worth knowing
+
+- Merged documents exist on our workers only during processing and expire automatically afterwards.
+- Merging never adds identifying metadata — but source files may carry some. Run [PDF Metadata Remover](/pdf-metadata-remover) on sensitive output.
+- Nothing you merge is readable by other users; jobs are isolated per session.
+
+## FAQ
+
+**Is there a page or file limit?**
+Practical limits come from total upload size rather than file count — dozens of typical documents merge fine.
+
+**Do bookmarks and form fields survive?**
+Bookmarks flatten during merging (page content is preserved perfectly). Interactive form fields survive when they live on the pages being merged.
+
+**Why does my merged file look rotated?**
+Individual scans often carry inconsistent rotation flags. Rotate pages at the source scanner, or rasterize-and-rebuild via [PDF to JPG](/pdf-to-jpg) then [JPG to PDF](/jpg-to-pdf).