How it works: Your ranking is based on the total of your payments. Bids are permanent; increasing your bid only costs you the difference. Equal bids are awarded to the oldest listing, and reaching first place costs at least €5 more than the currently top-ranked listing. That's the ranking logic; there are no other factors or rating system. The rules are available at overbid.eu/rules.
VAT management: The VIES REST API is called before a Stripe session is created. The results are cached so that top-ups are not redirected to VIES. Invalid results are cached for 24 hours to prevent typos from being blocked, and transient VIES errors are never cached. VIES is known for its sometimes unstable reliability depending on the member state; therefore, a retry system with a timeout and a "Notify me when I can try again" field are implemented. Verification is systematic. The legal name and country are taken from the VIES response and are displayed on the listing.
Configuration: a single Go executable, SQLite in WAL mode with a single-write connection, templ + htmx, Caddy as the front end, on an OVH VPS in Gravelines. The forum is served from a snapshot in memory that refreshes every 5 seconds or with each paid bid; the database is therefore not accessed with every request. Payment via Stripe with VAT self-assessment: self-assessment is applied when the VAT number is valid.
I am available to answer any questions regarding VIES integration or SQLite configuration.