If you work with PDF data extraction long enough, you run into the same question:
Should I use OCR, or is text/layout parsing enough?
The short answer: it depends on the source document.
The practical answer: you should detect document type early and choose the cheapest reliable path.
In this post, we will break down:
- Text-based PDFs vs scanned/image PDFs
- When text extraction is enough (and faster)
- When OCR is required
- How 0xPdf handles both automatically
- Performance and cost trade-offs
Text-based PDFs vs scanned/image PDFs
Not all PDFs are equal.
Text-based PDFs
These are generated digitally (from software exports, billing systems, etc.).
The text is selectable/copyable.
Typical examples:
- SaaS invoice exports
- E-invoices from ERP systems
- Bank statements generated from online portals
Scanned/image PDFs
These contain image data, not machine-readable text.
Typical examples:
- Scanned paper invoices
- Photos of receipts converted to PDF
- Faxed/printed documents re-uploaded
For these, plain text extraction often returns little or nothing useful. You need OCR.
When text extraction is enough (and faster)
Use text/layout parsing when your PDFs are mostly digital and clean.
Why:
- Lower latency
- Lower compute cost
- Fewer OCR-induced recognition errors
- Better throughput in bulk jobs
If your incoming docs are 90% machine-generated invoices, start with text extraction first.
In many production systems, this is the default path.
When you need OCR
Use OCR when documents are scanned, photographed, or have embedded text issues.
Common signs OCR is needed:
- Extracted text is empty or very sparse
- Page appears as one large image layer
- Line items or totals are unreadable in raw extraction
- Mobile-captured docs (skewed, noisy, blurry)
OCR is often the difference between "no parse" and "usable parse" on real-world messy data.
How 0xPdf handles both automatically
A robust pipeline should not force you to hardcode one mode forever.
0xPdf supports both strategies and can be used with a practical fallback model:
- Try text/layout extraction for speed
- If confidence/coverage is low, retry with OCR
- Return structured JSON in the same schema shape
That means your downstream systems do not care whether OCR was used -- they still receive the same JSON contract.
Example flow:
- Clean invoice PDF -> text parse path
- Scanned receipt PDF -> OCR path
- Same output schema -> same integration code
Performance comparison: with OCR vs without
Actual numbers vary by file quality and page count, but the pattern is consistent:
- Without OCR: faster, cheaper, ideal for machine-generated PDFs
- With OCR: slower, more compute-heavy, necessary for image documents
A practical benchmark pattern:
- 1-page digital invoice: text extraction significantly faster than OCR
- 10-page scanned statement: OCR slower but required for correctness
- Mixed workload: hybrid/fallback strategy gives best reliability/cost balance
If you care about both speed and accuracy, avoid "always OCR everything."
Cost implications
OCR costs more because it is computationally heavier.
If you run OCR on every document regardless of need, you will:
- Increase infrastructure/API costs
- Increase processing time
- Reduce throughput under load
A better strategy:
- Default to text/layout extraction
- Escalate to OCR only when needed
- Cache results for repeat documents
- Track OCR usage rate as an ops KPI
This keeps your unit economics healthy as volume scales.
Practical decision framework
Use this quick rule:
- Digital, selectable text PDF? Start without OCR.
- Scanned/photo-based or poor extraction quality? Enable OCR.
- Mixed unknown traffic? Use automatic fallback.
This gives you the best balance of latency, cost, and extraction quality.
Final thoughts
OCR and layout parsing are not competing strategies -- they are complementary tools.
If your goal is reliable production extraction, treat them as a routing problem:
- Fast path for clean digital docs
- OCR path for messy image docs
- Unified structured JSON output for the rest of your stack
That is the approach we use with 0xPdf to keep both developer experience and operational cost under control.
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