The Timologia API/microservice for TECTRA Ltd utilizes a LibreOffice ODS spreadsheet file that contains invoicing data originally generated using the timologia-processing parsing system applied on historical invoice spreadsheets, as well as invoice data entered manually into the spreadsheet since electronic invoicing became mandatory in Greece in October 2021.

The Timologia API exposes the data therein through GET endpoints as JSON, XML and plaintext, and provides user-friendly views for browsing the dataset by date, customer, customer region, and other attributes. It also provides an aggregated view of revenues per customer and per year.

Additionally, the software utilizes an async file watcher on the ODS file, which reloads and re-parses the information therein upon file modification.

The API utilizes htmx for live search across the dataset, and consumes two other bespoke APIs of the company:

• the VATcheck API for requesting information on the invoiced Tax Identification Number of each invoice, and
• the ProductItems API for requesting information on the invoiced positions.