ininvoice + A3 ERP: automate accounts payable and export a clean accounting entry

A3 ERP is the accounting engine for many Spanish tax advisor firms and SMEs that delegate accounting to an external office. Its strength is accounting. The weak spot when receiving a lot of paper is intake: someone still types invoices before generating the entry.

This guide explains how ininvoice fits in front of A3 so that someone stops typing, without touching the accounting base.

Why A3 doesn't do native three-way matching

A3 is accounting-first. Its mental model is the entry, the VAT book, the quarterly tax return. There it excels: tax validations, close, reconciliation with AEAT, SII and Verifactu. But three-way matching —cross-checking invoice, PO and delivery note line by line before approving payment— is not a native primitive.

It's not a defect: it's a scope. A3 serves companies where a formal PO does not always exist, the delivery note is not digitized and purchase-receipt verification is done manually. When volume grows —200, 500, 1,000 invoices/month— the model stops scaling. That's where ininvoice fits: touchless accounts payable in front of the entry.

End-to-end flow: email → ininvoice → A3

1. The invoice arrives at the client's mailbox (Gmail or Outlook) as PDF, XML or FacturaE.
2. ininvoice ingests, dedupes by hash and extracts structured header and lines.
3. Cross-checks line by line against PO and delivery note with 2% / EUR 1.50 OR-mode pre-tax tolerance. Without a PO, validates against supplier history.
4. Detects duplicates and applies risk score.
5. Assigns the accounting account by supplier or category (memory per client).
6. Generates the entry with VAT / withholding tax / concept / due-date breakdown.
7. Exports to A3 as a ready-to-post block.

The advisor sees the entry already formed in A3 with all fields squared. What they don't see is the hours of keyboard work the system has saved.

Data that reaches A3: account + VAT + withholding tax + concept

Field	Source	Notes
Supplier (tax ID / legal name)	Invoice	Validated against the supplier master in A3
Expense account	Memory per client	Learns from posted history
Taxable base	Invoice (pre-tax, line by line)	Sum of lines, not header totals
VAT (rate and amount)	Invoice	Breakdown per rate when multiple
Withholding tax (if applicable)	Invoice	Professionals, rentals, agricultural
Entry concept	Template per supplier	Configurable: date + concept + number
Due date	Invoice	For SEPA payment reconciliation
Cost center / project	Tag by supplier or category	If the client's A3 uses it

The VAT breakdown follows Spanish RD 1619/2012: bases per rate and amounts per rate. So the entry comes in coherent with the VAT book and SII.

Technical integration: CSV or API

Two ways to transport the entry from ininvoice to A3:

• Structured file export (CSV with the accounting import format A3 accepts). The common path in advisor firms: ininvoice publishes the daily batch and the advisor imports it for the client. Works on any A3 version.
• API connector. Modern A3 versions offer integration interfaces; scope depends on module and partner.

CSV is the safe start: any installation supports it. The API is evaluated client by client based on volume.

Multi-client advisor firms with A3

Typical case: a tax advisor firm with 30-50 client companies, all booked in A3, each with its own invoice mailbox. Without AP automation, the accounting clerk opens each PDF, types header and bases, and the quarterly close turns into a two-week race against Spanish form 303.

With ininvoice in front of A3: each client connects its mailbox once (48 h), ininvoice proposes the entry with accounting memory that learns from history, the advisor reviews batches and the close drops from a race to a verification. Each client has an isolated environment; the advisor operates all of them from a multi-client panel.

Verifactu and A3: combined impact for advisor firms

The AEAT Verifactu regulation (Spanish Royal Decree 1007/2023) requires verifiable invoicing systems. A3 covers the client's issuance when applicable. What Verifactu doesn't solve is the intake of received invoices: that's where the PDFs that someone has to read still live.

ininvoice prioritizes signed data (FacturaE / XML) over pixels when available. For an advisor firm exporting to A3 this means better extraction, clean traceability between document and entry, and lower SII discrepancy risk. More context in Verifactu and accounts payable.

Estimated savings: advisor with 300 invoices/client per month

Metric	Without AP automation	With ininvoice + A3
Average time per invoice	~3-5 min (keyboard + review)	~30 s (review)
Hours/month per client (300 invoices)	15-25 h	2-3 h
Hours/month for 10 clients	150-250 h	20-30 h
Freed capacity	—	~130-220 h/month
Typing errors / duplicates	Detected at close	Blocked at intake

AP productivity benchmarks are published by IOFM: teams with automated capture + matching process 3-5x more invoices per person than manual teams.

Activation time: 48 h per client

1. Day 0 — mailbox connection (Gmail / Outlook), read-only.
2. Day 0-1 — load supplier master and chart of accounts from A3 (CSV).
3. Day 1-2 — ingest the last 30-90 days as training. Accounting memory learns from history.
4. Day 2 — first real export batch to A3 ready to review.

No migration. No touching the accounting base. No lock-in.

Tax advisor checklist before activating

• [ ] Confirm the client's A3 ERP version (Eco / Professional).
• [ ] Identify accounting import format (standard CSV or custom).
• [ ] Agree on the inbox (Gmail, Outlook or firm alias).
• [ ] Export supplier master and usual accounts from A3.
• [ ] Define account rules for recurring suppliers (top 20 covers 80%).
• [ ] Decide whether withholding tax is automatic or reviewed case by case.
• [ ] Agree export frequency to A3: daily, weekly or pre-close.
• [ ] Designate batch reviewer before posting.

Frequently asked questions

Does ininvoice replace A3 ERP?

No. ininvoice is not an ERP and doesn't do accounting. It sits in front of A3: ingests, reads and reconciles before generating the entry. A3 remains the accounting base.

Does it work with all A3 versions?

CSV export works with any version that accepts accounting import. API depends on version and partner.

Who validates the entry before posting to A3?

The advisor or firm lead. ininvoice proposes, the human confirms. Review is not removed: typing is.

Does it learn each client's accounts?

Yes. Memory per client learns from history: if "Endesa" always goes to 628000, it keeps it. Configurable.

Is it compatible with SII and Verifactu?

Yes. Prioritizes signed data (FacturaE / XML) and exports a VAT breakdown coherent with SII. A3 remains the system that submits to AEAT.

What about paper invoices?

Works via scan or forwarded scanned document. Quality improves when the supplier issues electronically.

How is multi-client service billed?

By environment (client). The EUR 249/month plan covers up to 300 invoices/month; firms with several clients contract by aggregated volume or per client.

Three takeaways

1. A3 ERP is excellent as accounting-first; the missing piece is the automatic intake of invoices with three-way matching. That's where ininvoice fits in front.
2. The entry reaches A3 with account, VAT, withholding tax and concept already formed. The advisor reviews, doesn't type.
3. Activation is 48 h per client, with no migration and no touching the accounting base. Start with the client that receives the most invoices.

Related content

• Touchless accounts payable: what it means and how to measure it
• Three-way matching: how to cross-check invoice, PO and delivery note line by line
• ininvoice + Holded for accounts payable
• ininvoice + Sage for accounts payable
• IDP vs OCR for supplier invoices