Connected in the domain, separated in integration
NG One connects to every digital service Serbia operates, to banks, to devices in the warehouse and on the shop floor, and to the rest of the Konis family. How it connects is a decision rather than an accident: the flows are connected in the domain, but every service has its own adapter with its own lifecycle, statuses and retry. When SEF changes its rules in April, one adapter changes here — the e-delivery note, CRF and fiscalisation carry on.
- SEF, SEO, CRF, ePorezi
- CROSO, sick leave, eGovernment
- Fiscalisation LPFR/VPFR
- Banks and NBS
- REST and OpenAPI over everything
- Handhelds and shop-floor terminals
Why adapters rather than one “state module”
In 2026 the state merged invoicing, VAT records, delivery notes and the invoice registry into a single ecosystem. The easiest answer would be to merge all of it on our side too, into one module. It would also be the most expensive mistake available to us.
The connection between those flows is a business fact, and it is modelled as one: the invoice, the VAT record, the delivery note and the CRF entry share the same graph of business objects in the domain. When an invoice is issued, the record knows which lines produced it, the delivery note knows which goods it concerns, and the CRF ID sits on the invoice it belongs to. No data is copied between them and no operator maintains the link by hand. That is what connected in the domain means.
Towards the services, however, each is a separate adapter: its own lifecycle, its own synchronisation statuses, its own inbox and outbox staging, its own persistent watermark and its own per-document retry. The reason is mundane and therefore convincing: these are different systems, with different deadlines, different rules and different days on which they fail. An integration layer that assumes shared state across distinct external systems will one morning halt three flows because one broke. When SEF changes its rules in April, one adapter changes here, while the e-delivery note, CRF and fiscalisation keep working. That is what separated in integration means — a structural advantage without a dangerous coupling.
The other half of the decision is configurability. No link is configured in code: everything is set through the console, per tenant and per legal entity within a tenant — environment (demo or production), credentials in the secrets vault, which services are enabled, synchronisation schedules. Every link has a test-connection button and a health status on the compliance dashboard. Credentials never enter the database in clear text and never enter git. The consequence is a rule the system holds without exception: a consultant sets up a new client without a developer. A system in which every new link requires a code change turns every client into a project and every upgrade into a negotiation.
The third decision is that the data comes before the channel. Underneath every adapter sits a module that produces the document in its statutory form — UBL 2.1 for SEF, POPDV XML, PPP-PD XML — so the file stands on its own, and the adapter is transport rather than a source of truth. Two concrete things follow: a company that files by hand for reasons of its own files a correct file, with nothing changed in the system, and a company that files through the link knows the link carries exactly what an inspection would see. In a system where the link is the only route and the document is assembled at the moment of sending, its own errors reach the state services precisely as fast as the connection allows — with less chance that anyone catches them.
What NG One connects to
Five groups, organised by who is on the other side. Each link states the direction its data flows.
State services
Serbia runs more digital services than any ERP covers from a single system. NG One covers them — each as a separate adapter with its own lifecycle, synchronisation statuses, inbox/outbox staging and per-document retry.
SEF — e-Invoicing system
Outbound invoices sent as UBL 2.1 with status tracking (sent, accepted, rejected, cancelled), cancellations and advances, plus retrieval of inbound invoices under the 15-day accept-or-reject deadline. An inbound invoice does not stop in a mailbox — it enters procurement with a proposed link to its purchase order and goods receipt.
BidirectionalSEF VAT records
Aggregate and individual electronic VAT calculation records (EEO) and input-tax records (EPP), with recorded, corrected and cancelled statuses. Deadlines come from the compliance rule pack — EEO and EPP follow different rules and neither is hard-coded.
Outbound from NG OneSEO — e-Delivery note
Creating the electronic delivery note before goods move, with carrier and vehicle, tracking status through to receipt confirmation, the e-receipt and the link to the e-invoice. Excise goods follow their own flow.
BidirectionalCRF — Central Invoice Registry
Retrieving and storing the CRF ID against the invoice — derived from SEF from 1 July 2026 — tracking settlement per JBKJS and reconciling open items towards the public sector.
Inbound to NG OneePorezi (tax portal)
Preparing, validating and signing XML filings with a qualified certificate (PP PDV, PPP-PD, PDP and others), a register of filings and their status, and deadline reminders. The portal has no public API, so the flow is semi-automatic by the nature of the service — an authorised person performs the filing.
Outbound from NG OneCROSO (social insurance)
Registrations, deregistrations and changes to mandatory social insurance, derived from the employment contract already in the system. Automation goes as far as the portal permits; the remainder is prepared and recorded.
Outbound from NG OneeBolovanje (RFZO sick leave)
Retrieving e-certificates and linking them to the payroll run, electronic reimbursement claims and status tracking. The absence, the calculation and the RFZO receivable remain one record.
BidirectionaleGovernment — eMailbox and eID
Receiving acts from state bodies into the eMailbox and filing them into the registry book and DMS, with a number, a deadline and an owner. eID (ConsentID) is available as a sign-in option for signatories.
Inbound to NG Onee-Fiscalisation — LPFR and VPFR
Adapters for the local processor on a security element (LPFR) and the virtual processor (VPFR), all receipt types, QR verification, up to five days offline and the journal. The fiscal receipt ↔ SEF e-invoice link covers corporate cards and retail sales to the public sector.
Bidirectional
Banks and payments
Serbian banks share no common standard: one offers an API, another a file, another both under its own rules. The channel is therefore configuration per bank, not an assumption baked into code.
Statements and payment orders — per-bank channels
Automatic statement import through whichever channel the bank offers (folder, mail or API) and export of payment orders, with auto-matching that runs without a manual step. Format support expands against the real files of the banks a client actually uses — Halcom, OfficeBanking, Asseco and others.
BidirectionalNBS exchange rates
Automatic daily retrieval of the official exchange rate list from the National Bank of Serbia web service. Manual entry remains as a fallback — a rate must exist even on a day the service does not answer.
Inbound to NG OneIPS QR
Generating the IPS QR code on the invoice and the dunning letter, so the customer pays by scanning from their mobile bank without re-keying the reference number. The code is produced from the document's own data, not a separate tool.
Outbound from NG OneModel 97 and statement formats
The model 97 control number on the way out and its validation on the way in — the reference number is what makes statement matching exact rather than probable. Matching combines reference, amount and partner, and whatever it cannot link is left to a person with an explanation.
Bidirectional
The Konis ecosystem
NG One is the core of the family, not its replacement. The neighbouring products do what they do better than any ERP module would, and NG One orchestrates them while master data and finance stay in one place.
NG Commerce
The operating system of a trading business — catalog, sales channels, cart, checkout and orders. NG One supplies items, price lists, discounts and available stock, and receives back orders and payments that it turns into a sales order, a delivery note and an invoice.
BidirectionalNG Operations
The planning and production-control layer between ERP and warehouse — demand planning, MRP, scheduling, work orders and real-time realisation. NG One sends bills of materials, orders and materials, and receives production and consumption reporting that posts cost onto the work order.
BidirectionalNG Sara
An autonomous AI sales agent — it finds and qualifies new customers and runs cross-sell, upsell and win-back on existing ones across Viber, WhatsApp, email and social. NG One provides purchase history, open items and price lists, and receives opportunities and activities on the partner record.
BidirectionalNG Nora
An AI voice and chat agent for inbound calls and messages — it checks prices and stock, places orders, logs complaints and hands off to a person with full context, with no queue. NG One is the source of prices and stock and receives the order and the complaint as documents.
BidirectionalNG eFiscal
A class 3 software ESIR — it fiscalises paid turnover through the Tax Administration's V-PFR, with a QR code, a PDF by email and a REST API, with no register and no dedicated device. A company that fiscalises without a single device on the premises links it to NG One and gets the fiscal receipt as a document in the same chain as the invoice and the bank statement.
Bidirectional
Business tools
Everything NG One does, it does through its own API — there is no private path faster than the public one. That is a foundational decision, and the reason an integration with a tool we never anticipated does not have to be written in our code.
REST and OpenAPI over everything
Every capability is available over REST, with an OpenAPI specification from which a client can be generated in any language, plus a job queue for long-running work. The screen uses the same API your integrator does — if it works in the application, it works from outside.
BidirectionalWebhooks and automation rules
An event in the system triggers a rule on an event → condition → action pattern, and the action can be a call to your service, a notification or a task. Instead of your system polling ours in a loop, ours tells you when something happened.
Outbound from NG OneBI and data platforms
The reporting centre, OLAP and a spreadsheet over live data cover analytics inside the system, while export and the API open the same data to your Power BI, Tableau or warehouse. The dimensions that exist on a posting exist in the export — a project cut is not rebuilt outside.
Outbound from NG OneMicrosoft 365
An optional link to mail, calendar and documents through the tenant's Azure app registration. Deliberately optional: a system that does not work without Microsoft is a system you bought twice.
BidirectionalMCP server
NG One as a source of data and tools for AI agents over the Model Context Protocol, under the same permissions and the same audit as a user. An agent sees nothing the person it acts for cannot see, never leaves the tenant, and every call it makes enters the AI audit.
Bidirectional
Devices and terminals
The warehouse, the shop floor and the till do not work on the same screen as accounting. Devices are first-class clients of the system, with purpose-built screens — not a responsive rendering of a desktop form.
HHT — handheld terminals
Receiving, put-away, transfers, picking and stocktaking on a handheld, reading barcodes, lots, serials and expiry dates. The screens are designed for a gloved hand and one-handed use, and the task closes on the terminal — it is not re-entered at a desk later.
BidirectionalShop-floor terminals
Reporting production, material consumption and downtime from a terminal on the floor, in real time, with the work order as context. Licensed as a granule — a terminal on the floor is not paid for as a full user seat.
BidirectionalBarcode and SSCC printing (ZPL)
Direct label printing to thermal printers over ZPL, including SSCC codes for pallets and packing lists. Printing goes from the system to the printer, without a detour through a PDF and someone else's driver that rescales it.
Outbound from NG OneFiscal devices and the security element
The local fiscal receipt processor on a smart card (LPFR) or a file certificate for the virtual processor (VPFR), with a thermal receipt printer. Certificates and credentials live in the secrets vault per legal entity — never in the database in clear text and never in code.
Bidirectional
What is the hard part — the connection or the data?
The data, and it is not close. The connection is transport: authentication, format, statuses, staging, retry — work done once per service and maintained thereafter. The hard part is an invoice whose VAT treatment agrees with the record, a delivery note that matches the actual movement of goods, and a payroll run that survives an audit. That is why a module that produces the document in its statutory form sits underneath every adapter, so the file stands on its own: UBL 2.1 for SEF, POPDV XML, PPP-PD XML. File through the link and the link carries that file. File by hand, for reasons of your own, and you file the same file. A system that assembles the document only at the moment of sending delivers its own errors faster than anyone can notice them.
What does “connected in the domain, separated in integration” mean?
That the link between the invoice, the VAT record, the delivery note and the CRF entry is a business fact in our model — they share one graph of objects, so data is not copied between them — while towards external services each has its own adapter with its own lifecycle, statuses, staging and retry. The benefit is concrete: SEF can change its rules in April without a single change to the e-delivery note, and one service failing does not stop flows that have nothing to do with it. The alternative — a single “state module” holding shared state for every service — looks simpler on a diagram and breaks three processes at once about once a month.
Who configures the integrations — do we need a developer?
No. Every link is configured through the console, per tenant and per legal entity: environment (demo or production), credentials in the secrets vault, which services are enabled, synchronisation schedules. Each link has a test-connection button and a health status on the compliance dashboard, so a problem becomes visible before the Tax Administration notices it. That is a condition we imposed on the system rather than a by-product of the architecture: a consultant must be able to set up a new client without a developer. Credentials never go into code or git, and every service has a sandbox profile, so production is switched on per client when that client is ready.
Can we work with NG One from our own system?
Yes, through the same API our own screens use. REST with an OpenAPI specification covers every capability — there is no private path faster than the public one, so an integration you write is not a second-class citizen. There is a job queue for long-running work, webhooks on an event → condition → action pattern for notification, and an MCP server that opens NG One to AI agents under the same permissions and the same audit as a user. For one-off work there is the import/export framework with column mapping and a dry-run diff — not every exchange has to become an integration.
What if our bank has no API?
Then we use the channel it does have. The bank channel is configuration per bank rather than an assumption in code: statements are imported automatically through a folder, mail or an API depending on what the bank offers, and payment orders are exported in the format it accepts. Format support expands against the real files of the banks a client actually uses, not against a 2015 specification that has since changed. Auto-matching works the same whatever the channel: it combines the model 97 reference, the amount and the partner, and leaves whatever it cannot link to a person with an explanation rather than guessing.
Does NG One replace NG Commerce, NG Operations or NG eFiscal?
No. NG One is the core of the family and orchestrates them. NG Commerce runs the catalog, sales channels and checkout; NG Operations runs planning and production; NG Sara and NG Nora handle sales and inbound calls as AI agents; NG eFiscal is a certified software ESIR fiscalising through the V-PFR. NG One holds master data, finance and one business truth, and exchanges items, prices, stock, orders, work orders and realisation with them. A company already using one of them does not migrate — it connects. A company using none of them needs to take none.
What do we need to provide for the links to work?
What the service issues to you: an account and an API key per legal entity for SEF and VAT records, an SEO account, access to a CRF environment, registration with the NBS web service, sample real statement files for your banks, a qualified certificate for ePorezi filings, a legal entity eID account with authorisations for eGovernment, sick leave and CROSO, access to the TAP portal and a security element for fiscalisation, and an issuer's certificate for the seal and timestamp. You get the list at the start of the implementation, and each item is requested before the step it belongs to — the most common cause of integration delay is not code but waiting on an account issued by a third party.
What happens when a service does not respond?
Nothing that stops work. Every adapter has inbox and outbox staging, so a document waits in a queue instead of being lost; a persistent watermark, so after an outage it resumes where it stopped; and per-document retry, so one problematic invoice does not block the rest. For exchange rates, manual entry remains the fallback, and fiscalisation runs offline for up to five days as the law allows. The health status of every link sits on the compliance dashboard — the aim is that you notice a problem in time, rather than discover it when a deadline has passed.
Let us walk through your connections
Book a technical integration review. We go through the services you use, your banks and statement formats, the devices in your warehouse and the systems you are not replacing — and show what connects, in which direction and over which channel.