Example project · Document AI · Back office
Document AI for a distributor: from inbox to ERP, with a human where it counts.
“Tekton Supply” (a fictional company) distributes building materials in Ukraine. Four operators retype data from supplier invoices, waybills and acceptance acts into the ERP every day. Documents arrive as PDFs, phone photos and scans; formats change with every supplier. Here is how we would automate it without losing control.
By Nythrex EngineeringUpdated 3 min read
Illustrative scenario. This is an illustrative scenario that shows how Nythrex approaches this type of project. It is not a specific client case study: names, figures and timelines are examples.
- 01
Inbox & scans
Email, upload, mobile photos
- 02
Classify
Invoice · waybill · act · other
- 03
Extract
OCR + LLM → structured JSON
- 04
Validate
Totals · VAT · PO match
- 05
Review exceptions
Operator confirms or fixes
- 06
Post to ERP
Via API, with audit trail
Starting point
~6,000
documents per month
200+
suppliers with their own formats
4
operators retyping data
1
ERP (BAS) as the system of record
Example figures for an illustrative scenario.
The pain wasn’t only time. Typos in amounts and item codes caused reconciliation problems at month-end, and documents that arrived as photos from drivers were often skipped until someone chased them. A previous template-based OCR tool broke every time a supplier changed its invoice layout.
Approach
- 1
Sample and label
We would take a few hundred real documents across the top suppliers and document types, including bad photos, and label the fields that matter: supplier tax ID, document number and date, line items, quantities, prices, VAT, totals.
- 2
Extraction without templates
OCR for scans and photos, then an LLM that returns strict JSON against a schema. No per-supplier templates — new layouts work on day one, and the evaluation set tells us how well.
- 3
Validation with rules, not trust
Line totals must add up, VAT must match rates, the supplier must exist, and the document must match an open purchase order within tolerances. Anything that fails goes to review.
- 4
A review screen built for speed
Operators see the document and the extracted fields side by side, with the uncertain ones highlighted and the source region outlined. Confirm with one key; fix a field inline.
- 5
ERP integration
Validated documents are posted to BAS through its integration interface, with the original file attached and an audit record of who confirmed what.
Architecture
Inputs
- Shared mailbox
- Web upload
- Driver mobile photos
- Supplier EDI where available
Processing
- Queue
- Classification
- OCR
- LLM extraction (JSON schema)
- Confidence scoring
Validation
- Arithmetic & VAT
- Supplier registry
- PO matching
- Duplicate detection
People
- Exception review UI
- Keyboard-first
- Source highlighting
Systems (client-owned)
- BAS ERP
- Document archive
- Audit log
- Monitoring
What we would measure
| Metric | Why it matters |
|---|---|
| Field-level accuracy per document type | Shows where extraction is reliable and where review must stay |
| Straight-through rate | Share of documents posted without human edits — the real efficiency number |
| Review time per exception | The review screen’s job is to make the human part fast |
| Errors reaching the ERP | Must go down, not up — the safety metric |
| Cost per document | OCR and model usage at your volume, tracked monthly |
Discovery & labelling
Document sample · field schema
Extraction PoC
Accuracy by type
Validation & review UI
Rules · operator screen
ERP integration
Posting · audit
Parallel run
Old and new side by side
Lessons that transfer
- Photos from phones are a different problem from scans. Budget for image preprocessing and a clear “retake photo” path.
- Purchase-order matching catches more errors than extraction confidence does. Business rules are your best guardrail.
- Measure straight-through rate, not accuracy alone. 98% field accuracy can still mean most documents need a touch.
- Keep the original and the lineage. Auditors will ask where a number came from.
Frequently asked questions
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