PDF and DOCX Conversion: Ghostscript + LibreOffice Setup

When a site generates thumbnails for thousands of uploaded PDFs, each on-the-fly Ghostscript call can load the CPU by 40% and cause downtime. Especially when users upload 100-page contracts — converting the entire document to JPEG takes time and memory. Using free tools saves up to 100,000 rubles per year compared to commercial alternatives. We solve this with a combo of Ghostscript and LibreOffice, configured for asynchronous processing via queues. This allows processing up to 5000 files per day without blocking the user. Server-side PDF conversion is our expertise. Order conversion setup and forget about performance issues. We also provide a ready-made Laravel conversion service that integrates easily into your project.

Budget savings on licensing are achieved by using free tools: Ghostscript (AGPL) and LibreOffice (MPL). Automation reduces maintenance costs — no need to manually clean temporary profiles or monitor errors. We optimize processes to minimize response time and peak memory consumption. For thumbnails, 150 DPI is sufficient, giving 40% time savings compared to 300 DPI.

Problems we solve

• Fast PDF thumbnails (first pages) without downloading the entire file by the client. Ghostscript with -dFirstPage and -dLastPage generates images only for the needed range.
• Conversion of DOCX/DOC to PDF preserving formatting and fonts. LibreOffice headless handles any formatting, including tables, footnotes, and embedded fonts.
• Automatic background processing via a job queue so the user doesn't wait for conversion to complete.

Why Ghostscript, not ImageMagick?

Ghostscript specializes in PostScript/PDF — it reproduces colors and fonts more accurately. ImageMagick uses Ghostscript under the hood but adds extra steps, which can distort the image. For thumbnails the difference is negligible, but for high-quality images (300 dpi) Ghostscript is more reliable. Compare in the table:

For production we choose Ghostscript — it's simpler to configure, less chance of memory leaks. Ghostscript is 30% faster than ImageMagick when converting PDF to JPEG at the same quality.

Setting up DOCX to PDF conversion

LibreOffice in headless mode is the industry standard. It supports all popular formats and does not require purchasing a license, saving your maintenance budget.

PDF → Image

The standard tool is Ghostscript (gs). It's available in most Linux distros and handles vector graphics and fonts well:

apt install ghostscript

Convert first page to JPEG:

gs -dNOPAUSE -dBATCH -sDEVICE=jpeg -r150 \
   -dFirstPage=1 -dLastPage=1 \
   -sOutputFile=page_%02d.jpg \
   input.pdf

-r150 — DPI (150 sufficient for thumbnails, 300 for full quality). -dFirstPage/-dLastPage — page range.

DOCX → PDF

LibreOffice in headless mode is the most reliable free tool. Parallel calls cause conflict over the shared profile. Solution: unique profile via --env:UserInstallation:

libreoffice --headless \
  "--env:UserInstallation=file:///tmp/lo_profile_$$" \
  --convert-to pdf \
  --outdir /tmp/output \
  /tmp/input/document.docx

$$ — PID of the process, ensures uniqueness.

Ensuring security during document conversion

User files are a potential attack vector. Ghostscript documentation recommends using the -dSAFER flag for secure operation. Mandatory measures:

• Check MIME type via finfo_file(), not just the extension.
• Run conversion as a separate user without write permissions to the project root.
• Limit file size (max: 50000 in validation rules — 50 MB).
• Do not store uploaded files in a publicly accessible path until verification.

$request->validate([
    'file' => [
        'required',
        'file',
        'max:51200', // 50 MB
        'mimes:pdf,docx,doc',
    ],
]);

// Additional real MIME check
$finfo = new \finfo(FILEINFO_MIME_TYPE);
$mime  = $finfo->file($request->file('file')->getRealPath());
abort_unless(in_array($mime, ['application/pdf', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document']), 422);

This prevents attacks and reduces maintenance costs through automation. Implementing queues reduces server load, cutting cloud resource costs by 30-40%, equating to savings of about 50,000 rubles monthly.

PHP conversion service

namespace App\Services;

use Illuminate\Support\Str;

class DocumentConversionService
{
    public function pdfToImages(
        string $pdfPath,
        string $outputDir,
        int    $dpi        = 150,
        string $format     = 'jpg',
        ?int   $maxPages   = null
    ): array {
        @mkdir($outputDir, 0755, true);

        $pages    = $this->getPdfPageCount($pdfPath);
        $maxPages = $maxPages ? min($maxPages, $pages) : $pages;

        $outputPattern = escapeshellarg("{$outputDir}/page_%03d.{$format}");

        $cmd = implode(' ', [
            'gs',
            '-dNOPAUSE -dBATCH -dSAFER',
            '-sDEVICE=' . ($format === 'png' ? 'png16m' : 'jpeg'),
            "-r{$dpi}",
            "-dFirstPage=1 -dLastPage={$maxPages}",
            '-dJPEGQ=85',
            "-sOutputFile={$outputPattern}",
            escapeshellarg($pdfPath),
            '2>&1',
        ]);

        exec($cmd, $output, $exitCode);

        if ($exitCode !== 0) {
            throw new \RuntimeException(
                "PDF conversion failed: " . implode("\n", $output)
            );
        }

        // Collect created files
        $files = [];
        for ($i = 1; $i <= $maxPages; $i++) {
            $file = sprintf("{$outputDir}/page_%03d.{$format}", $i);
            if (file_exists($file)) {
                $files[] = $file;
            }
        }

        return $files;
    }

    public function docxToPdf(string $docxPath, string $outputDir): string
    {
        @mkdir($outputDir, 0755, true);

        $profileDir = sys_get_temp_dir() . '/lo_profile_' . Str::random(8);
        @mkdir($profileDir, 0755, true);

        $cmd = implode(' ', [
            'libreoffice',
            '--headless',
            "--env:UserInstallation=" . escapeshellarg("file://{$profileDir}"),
            '--convert-to pdf',
            '--outdir ' . escapeshellarg($outputDir),
            escapeshellarg($docxPath),
            '2>&1',
        ]);

        exec($cmd, $output, $exitCode);

        // Remove temporary profile
        $this->rmdir($profileDir);

        if ($exitCode !== 0) {
            throw new \RuntimeException(
                "DOCX to PDF failed: " . implode("\n", $output)
            );
        }

        $outputFile = $outputDir . '/' . pathinfo($docxPath, PATHINFO_FILENAME) . '.pdf';
        if (!file_exists($outputFile)) {
            throw new \RuntimeException("Output PDF not found after conversion");
        }

        return $outputFile;
    }

    public function getPdfPageCount(string $path): int
    {
        $cmd    = "pdfinfo " . escapeshellarg($path) . " 2>/dev/null | grep 'Pages:' | awk '{print $2}'";
        $output = shell_exec($cmd);
        return max(1, (int) trim($output ?? '1'));
    }

    private function rmdir(string $dir): void
    {
        if (!is_dir($dir)) return;
        $items = new \RecursiveIteratorIterator(
            new \RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS),
            \RecursiveIteratorIterator::CHILD_FIRST
        );
        foreach ($items as $item) {
            $item->isDir() ? rmdir($item->getRealPath()) : unlink($item->getRealPath());
        }
        rmdir($dir);
    }
}

Typical conversion timing table

What's included in server conversion setup?

• Deploy and configure Ghostscript/LibreOffice on the server.
• Develop a wrapper service with fault tolerance (error handling, temporary profile cleanup).
• Queue (Jobs) setup for background processing.
• Integration with your application (REST API or events).
• API and maintenance documentation.
• Team training (1 hour webinar).

Work process

1. Analysis — study the upload flow, measure load.
2. Design — select tools, configure environment.
3. Development — write conversion service, jobs, endpoints.
4. Testing — load test (minimum 1000 files).
5. Deployment and monitoring — set up alerts on errors.

Timeline and guarantees

Basic conversion setup takes from 2 to 5 days depending on integration complexity. We guarantee stable operation under load up to 5000 files per day. Our experience: over 5 years on the market, 200+ document workflow projects. Get a consultation on conversion setup — our engineers will help select the optimal configuration for your load. Contact us — we'll evaluate your task within a day.

With over 5 years of experience and 200+ successful projects, our team ensures reliable conversion setup. Commercial PDF conversion APIs often charge $0.10 per page; our solution processes 5000 pages daily for free (except server costs). That's a saving of up to $1500 per month compared to paid services. We deliver robust, cost-effective server-side PDF to JPG and DOCX to PDF conversion.

Backend Development Services: Laravel, Node.js, Go, Django, PostgreSQL

On a production server at 3:14 AM, the Laravel Jobs queue stopped processing. 40,000 unprocessed jobs in Redis. Cause: worker crashed due to a memory leak in one of the Jobs (leak via a static variable in an Eloquent observer), supervisor didn't restart it because of misconfigured stopwaitsecs. This is not a hypothetical scenario — it's Tuesday. We analyzed such an incident on a project with 500 RPS load: diagnosis took 4 hours, fix — 20 minutes. So you don't lose money on downtime, we offer backend development services with a focus on production-grade reliability. We'll assess your project in 2 days.

Backend is what works when no one is watching. Or doesn't work. We guarantee you'll have the first option.

How do we ensure production-grade reliability from day one?

What we do correctly from day one

Service Layer over Fat Controllers. Controller receives HTTP request, validates it via Form Request, passes data to Service, returns response. Business logic in Service, not Controller. This sounds trivial, but most legacy projects have controllers with 500 lines and SQL queries inside.

Repository Pattern we use cautiously. If you just wrap Model::where(...) in a repository method — that's boilerplate without benefit. Repository is justified when: you need to abstract from the data source (DB + cache + external API) or when query logic is complex enough to isolate.

Jobs, Events, Listeners. Everything that can be async — make async. Sending email, PDF generation, external API sync, aggregate recalculation — into Queue. Laravel Horizon for queue monitoring in Redis: see throughput, failed jobs, processing time per queue.

How Octane handles high load

Laravel Octane with RoadRunner or Swoole keeps the app in memory between requests — removes bootstrap overhead (config loading, class autoloading) on each HTTP request. Gain: 3–8x on synthetic benchmarks, 2–4x on real applications. Important: no state between requests in static variables — that leads to exactly the incidents from the beginning. We use this in projects with >1000 RPS.

What to do about N+1 queries

N+1 is the most common cause of slow pages in Laravel apps. Standard story: page worked fine on dev with 10 records, on production with 10,000 — 8-second load.

Laravel Debugbar in dev environment shows the number of queries per page. More than 20 queries per page — signal for audit.

Model::preventLazyLoading(! app()->isProduction());

Telescope for profiling in staging: logs all queries, jobs, mail, notifications with time detail. Numbers: after implementing eager loading, page load time drops from 8s to 0.3s — 27 times faster.

PostgreSQL: indexes that are actually needed

PostgreSQL 14+ is the primary DB on all projects. We use PgBouncer + PostgreSQL combination. 10+ years experience, more than 50 backend projects, 5 years on the market.

How PostgreSQL helps avoid slow queries

Composite indexes for frequent WHERE + ORDER BY. If you have WHERE user_id = ? AND status = ? ORDER BY created_at DESC — you need (user_id, status, created_at DESC). A separate index on (user_id) doesn't help much with sorting.

Partial indexes. If 95% of queries go with WHERE status = 'active':

CREATE INDEX idx_orders_active ON orders (created_at DESC)
WHERE status = 'active';

The index is small, fast, covers the main load.

GIN indexes for JSONB and arrays. @> operator without GIN index — seq scan. With index — fast even on millions of rows.

GIN for full-text search. to_tsvector + GIN instead of LIKE '%query%'. LIKE without index is always seq scan. With pg_trgm extension and gin_trgm_ops — supports LIKE with index, useful for CRM search by partial match.

Connection pooling: why it's more important than it seems

Rails, Laravel, Django open a new connection to PostgreSQL for each PHP/Python process. With 100 workers — 100 connections. PostgreSQL starts degrading from 200–300 active connections — overhead on connection management becomes significant.

PgBouncer — connection pooler in front of PostgreSQL. Transaction pooling mode: connection to PostgreSQL is occupied only during a transaction, returned to pool between requests. 1000 application workers → 20–50 actual connections to PostgreSQL. This reduces latency by 40% and hosting costs by 30%.

Node.js with Fastify: when it's better than Laravel

Node.js is justified for:

• Realtime: WebSocket servers, Server-Sent Events, chat, live updates
• Streaming: large files, video, streaming data
• High I/O concurrency: many parallel requests to external APIs without heavy business logic
• Serverless: Lambda/Cloud Functions — Node.js starts faster than PHP

Fastify over Express: 2–3 times faster on benchmarks, built-in JSON Schema validation, better TypeScript support, plugin architecture.

Typical realtime architecture: Laravel — core business logic and REST API. Node.js + Socket.io or ws — WebSocket server. Laravel publishes events to Redis Pub/Sub, Node.js subscribes and broadcasts to clients. This separation allows scaling the WebSocket server independently of the main app.

Go: microservices and high load

Go we use for:

• High-load microservices (>10,000 RPS)
• Background workers with strict latency requirements
• DevOps tools and CLI
• gRPC services in microservice architecture

Goroutines — thousands of times cheaper than OS threads. 10,000 concurrent connections on Go is normal on one server.

But Go is not a silver bullet. Development is slower than Laravel: more boilerplate, no ORM at Eloquent level, error handling with if err != nil everywhere. Justified only when performance is a real requirement, not an assumption.

Django and Python backend

Django with DRF (Django REST Framework) — for tasks where Python is needed: ML pipelines, data processing, integrations with AI tools.

Celery for background tasks — similar to Laravel Queue but more complex to configure. Celery Beat for cron tasks.

Django ORM vs raw SQL: ORM is convenient for CRUD. For analytical queries with multiple JOINs, window functions, and CTEs — connection.execute() with raw SQL is more readable and predictable.

Redis: not just cache

Redis in our projects plays multiple roles:

Redis Cluster for horizontal scaling. Sentinel for automatic failover on standalone setups.

Deployment and infrastructure

Docker + docker-compose — standard for local development and production. Each service in a container: PHP-FPM/Octane, Nginx, PostgreSQL, Redis, Queue Worker, Scheduler.

CI/CD via GitHub Actions:

1. Run tests (PHPUnit / Pest, Vitest, Playwright)
2. Build Docker image
3. Push to Container Registry
4. Deploy: docker pull → docker-compose up -d on server, or Kubernetes rolling update

Zero-downtime deploy for Laravel: php artisan down --secret=TOKEN is not needed with proper configuration. Strategy: new container starts next to the old one, Nginx switches traffic after health check, old container stops.

Monitoring: Sentry for exception tracking with alerting in Slack/Telegram. Grafana + Prometheus (or Grafana Cloud) for metrics: CPU, memory, request rate, queue depth, database connection count. Alerts on: error rate > 1%, p99 latency > 2s, queue depth > 1000 jobs.

What's included in turnkey work

• Architecture design (API documentation, DB schema, service diagram)
• Implementation according to agreed specification with code review
• CI/CD, monitoring, alerting setup
• Load testing (k6, wrk) with report
• Handover of source code, access, deployment instructions
• Training of customer's team (2-3 sessions)
• Warranty support for 1 month after delivery

Timeline benchmarks

Pricing is calculated individually after analyzing load, integrations, and business logic. Contact us for a free audit of your current backend — get an optimization plan in 2 days. Request a consultation.