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Automated Solutions

Automating invoice processing with RPA and document AI

A blueprint for automating accounts payable end to end — extraction, validation, matching and exception routing — with honest handling of the cases the automation should not attempt.

8 min read
  • Azure Document Intelligence
  • UiPath
  • Power Automate
  • ERP APIs
  • Azure Functions
Finance team reviewing invoice processing on office workstations

This is a blueprint, not a client case study. The situation described is a composite of the conditions we design for, not a named engagement. Targets below are measures we would baseline and report against — not results already achieved.

The situation

What we'd be walking into

A shared services finance function processes somewhere around 14,000 supplier invoices a month across two entities. Invoices arrive by email as PDFs, as scanned paper, and through a supplier portal that exports a weekly file in a format nobody chose.

Six people key invoice data into the ERP. A seventh handles the exceptions — mismatched purchase orders, missing GRNs, invoices for entities that no longer exist. Month-end accrual is a scramble because nobody knows what is sitting unprocessed.

A previous automation attempt built four bots that worked until the ERP was upgraded. Two were repaired, two were quietly abandoned, and the team's confidence in automation went with them.

Constraints that shape everything

  • A confidently wrong extraction is worse than no extraction

    An invoice paid at the wrong amount costs more to unwind than it cost to key manually. Confidence thresholds have to route uncertainty to a person rather than guess.

  • The exception rate is the whole problem

    Roughly a third of invoices have something wrong with them. An automation that handles only the clean two-thirds and dumps the rest changes very little.

  • The ERP will be upgraded again

    Brittle UI automation against an upgrading ERP is exactly what failed last time. Integration must prefer APIs and must be monitored for silent failure.

  • Audit and segregation of duties apply

    An automated process that creates and approves its own payments fails the control. The automation posts; it does not approve.

  • The team is sceptical

    Credibility has to be rebuilt with a parallel run on real invoices, not with a demo on curated samples.

Architecture

How the pieces fit

The shape of the solution, before any of the detail below.

Confidence-gated invoice processing

Email PDFsScanned paperSupplier portalClassifydocument type + entityExtractheader + line itemsConfidenceper fieldReview queuehuman-in-the-loopThree-way matchPO · GRN · invoiceException taxonomyclassified by causeERPpostFixupstreambelow thresholdabovecorrectedno matchStraight-through path shown in accent. Every exception is classified by cause, and the top causes are fixed upstream rather than serviced indefinitely.
Extraction is scored per field. Anything below threshold routes to a human review queue with the document alongside, rather than being posted on a guess.
Our approach

The decisions that matter

These are the calls that determine whether the engagement works — most of them made before any build starts.

1

Qualify before building anything

We measure the real distribution first — volume by channel, exception rate by cause, actual handling time per invoice type. That produces a ranked view of where automation pays back and, just as importantly, which invoice categories should stay manual because their variability makes automation a maintenance liability.

2

Redesign before automating

A meaningful share of exceptions are caused upstream: suppliers sending invoices without PO references, a portal export format that loses data, tolerance settings that were never revisited. Fixing those removes exceptions rather than automating them, and it is cheaper than any bot.

3

Extract with confidence thresholds, not certainty

Layout-aware document AI extracts header and line-level fields with a per-field confidence score. Fields above threshold pass through; anything below routes to a review queue with the extraction pre-populated and the source document beside it. Thresholds are tuned per field, because a wrong supplier name and a wrong total carry very different costs.

4

Build the exception taxonomy first

Every exception is classified by cause — PO mismatch, missing receipt, tolerance breach, unknown supplier, duplicate. Each class gets a defined handling path, and volume by class drives the improvement backlog. Without this, the exception queue is just a different inbox.

5

Integrate over APIs, monitor for silence

ERP posting goes through APIs wherever they exist, with UI automation as a last resort and explicitly flagged as fragile. Synthetic transactions run daily so a broken integration is detected by monitoring rather than by a supplier chasing payment.

6

Parallel run to rebuild trust

The automation runs alongside the manual process on live invoices for a defined period, with variance analysed and explained. The business case is then built on the team's own data, which is also what earns the team's confidence back.

Delivery plan

Phases, with indicative timing

Durations are indicative for an engagement of this shape. Yours would be sized during assessment.

  1. 01Weeks 1–3

    Discover & qualify

    Measure the real process — volumes, channels, exception causes and handling times — and produce a ranked automation scope with an explicit do-not-automate list.

    Activities

    • Volume and channel analysis across all intake routes
    • Exception sampling and root-cause classification
    • Task-level time capture with the processing team
    • Suitability scoring and payback modelling
    • Do-not-automate list with reasoning documented
  2. 02Weeks 4–6

    Process redesign

    Remove the exceptions that are caused upstream, then design the target process with its exception taxonomy and control points.

    Activities

    • Supplier onboarding and PO reference remediation
    • Portal export format correction
    • Tolerance and matching rule review with finance
    • Exception taxonomy with defined handling paths
    • Control and segregation-of-duties design
  3. 03Weeks 7–14

    Build & pilot

    Develop extraction, matching and posting, then run in parallel with the manual process on live invoice volume.

    Activities

    • Document classification and extraction model configuration
    • Per-field confidence threshold tuning
    • Three-way matching logic and tolerance handling
    • Review queue interface for below-threshold fields
    • Parallel run on live volume with variance analysis
  4. 04Weeks 15–20

    Deploy & ramp

    Phased production rollout by invoice category and entity, with monitoring live from the first transaction.

    Activities

    • Category-by-category volume ramp
    • Monitoring, alerting and synthetic transaction checks
    • Operator training on the review queue
    • Benefits tracking against the week-one baseline
    • Runbook and failure escalation procedures
  5. 05Ongoing

    Operate & improve

    Steady-state operation with exception causes reviewed on a cadence and the top drivers fixed rather than serviced indefinitely.

    Activities

    • Monthly exception review by cause and volume
    • Extraction accuracy monitoring with retraining triggers
    • Upstream system change impact assessment
    • Straight-through rate improvement backlog
    • Extension to adjacent processes once stable
Measurement

What success would look like

Every one of these is baselined before work starts, so the comparison at the end is defensible rather than flattering.

Success measures for Invoice automation with RPA + document AI, with targets and measurement method
MeasureTarget
Straight-through processing rateBaselined in pilot, improved quarterlyShare of invoices posted with no human touch, tracked by invoice category rather than as a single blended figure.
Extraction accuracy above thresholdValidated against manual keying in parallel runField-level comparison between automated extraction and manual entry across the full parallel-run sample.
Exception volume by causeTop three causes reduced, not just routedException taxonomy counts tracked monthly, with upstream fixes prioritised by volume.
Handling time per invoiceMeasured on a consistent definitionBefore and after comparison using the same task boundaries, so the improvement figure is defensible.
Automation availabilityFailures detected by monitoring, not by suppliersSynthetic daily transactions plus alerting on queue depth and posting failures.
Risk

What could go wrong, and what we'd do about it

Named up front. A risk register written after something goes wrong is just a post-mortem.

ERP upgrade breaks the automation again

API-first integration with UI automation minimised and explicitly flagged. Upstream change impact assessment is part of ongoing support, not an afterthought.

Confidence thresholds set too permissively

Thresholds are derived from parallel-run data per field, and reviewed monthly against actual error rates rather than set once at go-live.

Exception queue becomes a new bottleneck

Exception taxonomy drives an improvement backlog targeting causes. Queue depth is monitored and alerted, and the top causes are fixed upstream.

Team resistance from the previous failed attempt

Parallel running on live data with transparent variance reporting, and the processing team involved in threshold tuning rather than presented with a finished system.

Your situation won't match this exactly.

It never does. Tell us where yours differs and we'll tell you honestly whether we're the right people for it.

Or email us directly at reachus@segakiv.com