What custom ERP integration involves
If you run a custom or in-house ERP, making it compliant means it must issue invoices that transmit to KRA eTIMS and validate, with the control number and signature. There is no shortcut connector; you build the integration to KRA's specification.
The integration uses KRA's control unit approach, OSCU (Online Sales Control Unit) or VSCU (Virtual Sales Control Unit), and the eTIMS API, mapping your ERP's invoice data to the eTIMS fields and handling transmission, responses and errors. The authoritative reference for endpoints, payloads and requirements is KRA's official eTIMS API documentation, which changes over time. Plan for certification, sandbox testing and ongoing maintenance, and weigh that cost against running invoicing on compliant software and reconciling.
The cheapest eTIMS integration is often the one you do not have to build, certify and maintain yourself.
How to approach it
A practical path. Confirm exact technical details against KRA's official documentation.
- 1
Get KRA's official documentation
Obtain and work from KRA's current eTIMS API documentation, which defines the endpoints, payloads, control units and requirements.
- 2
Choose OSCU or VSCU
Select the control unit approach that suits your connectivity and architecture, per KRA's requirements.
- 3
Map and build the integration
Map your ERP's invoice data to the eTIMS fields, build transmission and error handling, and capture buyer PINs and correct tax treatment.
- 4
Certify, test, then maintain
Certify as KRA requires, test in the sandbox, go live carefully, and maintain the integration as requirements change.
What to check before you build
Building against unofficial specs
Use KRA's official documentation as the source of truth. Third-party summaries go stale and cause validation failures.
Underestimating ongoing maintenance
A custom integration must be maintained as KRA evolves the system. Budget for upkeep, not just the initial build.
Not handling errors and offline
Build proper error handling and, if you need it, offline behaviour, so transmissions are reliable in real conditions.
A team weighs build versus buy
A business in Nairobi with a bespoke ERP scoped an eTIMS integration: control unit approach, field mapping, error handling, certification and testing.
They estimated not just the build but the ongoing maintenance as KRA's requirements changed, and compared it to running invoicing on compliant software and reconciling to their ERP.
For their volume, the custom build made sense; a smaller sister company chose compliant software instead, avoiding the build and upkeep entirely. Both stayed compliant.
Trading without eTIMS-compliant tax invoices risks KRA penalties, blocked VAT input claims for your customers, and receipts a business buyer cannot expense.
Veira signs every sale to KRA eTIMS automatically, so each receipt is compliant the moment it prints, with no separate device to reconcile.
When you can skip the integration
The biggest decision here is whether you need to build an integration at all. Veira is already a compliant eTIMS system: it issues compliant KRA invoices automatically, applies the right tax treatment, captures the buyer PIN, transmits to KRA, and works offline. For many businesses that removes the need to build, certify and maintain a custom integration yourself.
If you do run an ERP or a custom stack, weigh the cost of building and maintaining an integration against running point of sale and invoicing on Veira and reconciling. Veira runs from KES 2,999 a month with a free terminal and a 30-day money-back guarantee. See how Veira works, or book a free demo to talk through your setup.
Frequently asked questions
How do I integrate a custom ERP with eTIMS?
What is the authoritative reference for the build?
Should I build or use compliant software?
Do I need to certify a custom integration?
Do I have to build my own eTIMS integration?
Where is the authoritative eTIMS technical spec?
eTIMS custom ERP integration comes down to the concepts above plus KRA's official documentation for the exact details, and for many businesses the simplest path is compliant software that handles it for you. See how Veira works, or book a free demo. Always build against KRA's current official eTIMS documentation.