An in-house calibre for accounts payable.
Watchmakers who design and build their own movement call it an in-house calibre. Calibre is ours: a document model we run ourselves reads every supplier invoice, GST rules and your purchase orders prove it, and it posts to the ERP you already run.
Most AP products rent their intelligence. We built the movement.
A general-purpose AI service sees your invoices, forgets them and answers to someone else’s priorities. Calibre’s reader, rules and calibration are ours, and they run on private infrastructure we operate.
Our reader
A document model fine-tuned for Indian invoices and hosted by us. No invoice is sent to a third-party AI API, and every value it reads must point to the page.
Our rules
A rules engine runs beside the model on every invoice: GSTIN check digits, tax type, rate slabs, arithmetic, amount in words and the signed e-invoice QR.
Our regulation
Confidence calibrated against verified outcomes, so an invoice clears on its own only when the evidence supports it, and reaches a person when it does not.
| # | Description | HSN | Qty | Unit | Rate | Amount |
|---|---|---|---|---|---|---|
| 1 | Pump housing, SG iron, machined | 84139190 | 120 | NOS | 1,450.00 | 1,74,000.00 |
| 2 | Valve body, CF8M stainless | 84819090 | 60 | NOS | 2,380.00 | 1,42,800.00 |
| 3 | Impeller blank, cast | 73259999 | 200 | NOS | 312.50 | 62,500.00 |
Payment 45 days from invoice date
Authorised signatory
Watch one invoice go through the movement.
- 01 · Layout
The page is found before the words.
Turned upright, then divided into regions: supplier, buyer, lines, totals and signature.
- 02 · Words
Every word, with where it sits.
Native PDF text is used exactly. Scans and photos are read and every word is placed on the page.
- 03 · Fields
Values read by our model, each tied to its words.
Our document model reads each field and a rules engine reads beside it. Nothing the model says counts unless it can point to the page.
- 04 · Arithmetic
The numbers add up, to the rupee.
Lines, tax and total agree within ₹1 or 0.5%. Then the amount in words is read and compared with the figures.
1,74,000.00 + 1,42,800.00 + 62,500.00 = 3,79,300.00
3,79,300.00 × 18% = 68,274.00 IGST
3,79,300.00 + 68,274.00 = 4,47,574.00 ✓ words agree - 05 · Identity and GST
Who sent it, and is the tax right?
GSTIN check digit, the PAN inside it and the state. Telangana to Maharashtra is an inter-state supply, so IGST is expected, and 18% is a valid slab.
36AAJCG4821K1ZE · check digit E ✓
PAN AAJCG4821K · company ✓ · state 36 Telangana ✓
Place of supply 27 → inter-state → IGST ✓ - 06 · Signature
The signed QR settles it.
The e-invoice QR is verified against the e-invoice portal’s published keys. Supplier GSTIN, invoice number, date, total and IRN become authoritative and are locked.
RS256 signature ✓ · IRN eb671be2…4edc
Locked: GSTIN · invoice no. · date · total - 07 · Decision
One field to confirm, so a person confirms it.
Everything passed except the PO number, printed as “Your ref” in the footer of this vendor’s first invoice. It goes to review with that reason attached.
- 08 · Correction
Correct it once. Calibre remembers.
The reviewer confirms the PO. Vendor memory records how this vendor prints it, so the next invoice clears on its own.
The parts of the Calibre movement
- i
IntakeMainspring
Invoices arrive by email or upload, are scanned for malware and queued. Nothing is read until the file is proven safe.
- ii
VisionEscapement
Pages are turned upright, laid out and read word by word, each word with its position on the page.
- iii
Reader modelBalance wheel
Our own document model, fine-tuned for Indian invoices and run on infrastructure we operate, reads every field. Every value must point to the page.
- iv
Proof tiersJewels
Four tiers of checks run beside the model on every invoice: form, arithmetic, GST and identity, and policy.
- v
CalibrationRegulator
Confidence calibrated against verified outcomes, so an invoice clears on its own only when the evidence supports it.
- vi
LearningRotor
Every verified invoice becomes vendor memory, agreeing corrections become rules, and every release brings a better reader.
- vii
InfrastructureCase back
Tenant isolation, a separate key for every customer, pointers instead of documents, and private compute.
Built to be right on 99% of the invoices it clears on its own.
A vendor earns clearance the way a movement earns its certificate: by evidence over time. Until the evidence is there, Calibre asks a person and shows them why.
- At least three verified invoices from this vendor
- Calibrated confidence on every critical field
- Quality checks on that vendor at or above 99%
Self-winding. Every verified invoice winds it.
An automatic movement winds itself from the motion of the wrist. Calibre gets better from the work your team already does: every correction is kept as evidence, with where it sits on the page, and it is yours alone.
- Next invoice
Vendor memory and rules
What a reviewer verifies about a vendor is remembered for that vendor. Five corrections that agree become a rule, proven in the background before it is trusted.
- Every week
Calibration
Confidence is re-fitted to verified outcomes, so “sure” keeps meaning sure.
- Every release
A better reader
Trained on pooled, pseudonymised data from customers who opt in, and released only when it beats the reader before it on vendors it has never seen.
Six GST checks, on every invoice.
Built for the Indian invoice from the first line of code: identity, place of supply, rate slabs, arithmetic, amount in words and the signed e-invoice.
- E
GSTIN check digit
Computed from the first fourteen characters and compared with the one printed.
- 36→27
Place of supply
Telangana to Maharashtra is inter-state, so IGST, not CGST and SGST.
- 18%
Rate slab
Every rate must sit on a valid GST slab.
- ±₹1
Arithmetic
Lines, taxes and total agree, to within ₹1 or 0.5%.
- = ₹
Amount in words
“Four Lakh Forty-Seven Thousand…” must equal the figures.
- RS256
Signed QR
The e-invoice QR is verified against the portal’s published keys.
From intake to gateways. The whole movement on one plate.
Hover over any station. Invoices that pass every check clear and post; anything Calibre cannot prove goes to review, and the correction flows back into memory.
- 01
Intake
Email or upload. Every file is scanned for malware before anything reads it.
- 02
Vision
Pages turned upright, laid out and read word by word, with positions.
- 03
Reader
Our own document model reads each field and points to its words.
- 04
Proof
Four tiers of checks: form, arithmetic, GST and identity, policy.
- 05
Decision
Clears with calibrated confidence, or goes to a person with the reason.
- 06
Review
The document beside its fields, evidence one click away. Approval chains apply.
- 07
Memory
Corrections kept as evidence. Vendor memory and rules feed the next read.
- 08
Gateways
A preflight, then the invoice is posted once to your ERP with the PDF attached.
Fits the case you already wear.
Calibre posts verified invoices into the ERP you run, through one connector platform with preflight checks, versioned mappings and postings that never happen twice. Running something else? We connect new ERPs in days.
- CalibreOne connector platform
- S/4HANA
- NetSuite
- Fusion Cloud ERP
- M3
- LN
- TallyPrime
- Tally.ERP 9
- Business One
Closed to the world. Open to you.
Your invoices are read on private GPU infrastructure we operate, never by a shared AI service, and every decision Calibre makes can be traced back to the page.
- No invoice is sent to a third-party AI API. The rule is enforced in our code, not just written in a policy.
- Every customer is isolated at every layer, with its own encryption key.
- Services pass pointers, never documents. No invoice content is written to logs.
- Sharing for model training is off unless you turn it on, and identifiers are replaced before anything is pooled.
- An audit trail of every action, and results you can reproduce: each value records its source, model version and prompt.
Four references from the industries we know best.
Illustrative scenarios built from how finance teams in each industry work today.
- Ref. 01Manufacturing
A pharma API manufacturer with three plants
Raw-material invoices run to dozens of lines, arrive at every plant, and are keyed line by line before anyone checks them against the purchase order.
Illustrative scenarioSAP S/4HANA → - Ref. 02Construction and infrastructure
A mid-size EPC contractor working in nine states
Subcontractor and supplier bills reach site offices first.
Illustrative scenarioTallyPrime → - Ref. 03Real estate
A residential developer with fourteen project companies
Contractor and consultant invoices are addressed to the wrong project company, approvals run over email, and evidence is assembled only when the auditor asks for it..
Illustrative scenarioOracle Fusion Cloud ERP → - Ref. 04Wholesale and distribution
The Indian arm of a global pharma distributor
Suppliers send one PDF holding many invoices, long invoices are keyed line by line, and e-invoice details are retyped from the page..
Illustrative scenarioOracle NetSuite OneWorld →
Questions finance teams ask
Does Calibre send our invoices to ChatGPT or another AI service?
No. Calibre reads invoices with its own document model, run on private infrastructure we operate. No invoice is ever sent to a third-party AI API.
Which ERPs does Calibre work with?
SAP S/4HANA, SAP Business One, Oracle NetSuite, Oracle Fusion Cloud ERP, Infor M3, Infor LN, TallyPrime, Tally.ERP 9 and Zoho Books. If you run something else, our connector platform connects new ERPs in days.
How does Calibre check GST?
Every invoice passes four tiers of checks: the GSTIN’s check digit, PAN and state; tax type against the place of supply; rate slabs and arithmetic to the rupee; the amount in words; and the signed e-invoice QR, verified against the portal’s published keys.
How accurate is Calibre?
Calibre is built to be right on 99% of the invoices it clears on its own. Anything it cannot prove goes to a person with the reason attached. Your demo includes a replay of your own invoices, so you can judge it on your data.
Does Calibre learn from our corrections?
Yes. Every correction is kept as evidence. It becomes vendor memory for the next invoice, recalibrates confidence, and trains a better reader with every release, using pooled, pseudonymised data only from customers who opt in.
Where is our data kept?
Calibre is built to keep your invoices in India, isolated per customer with its own encryption key. Services pass pointers, never documents, and no invoice content is written to logs.
See it on your own invoices.
Send us a month of invoices. We replay them against your ERP’s records and show you, vendor by vendor, what Calibre would have cleared, and why the rest would have gone to a person.