Billing engines are built for rate x volume, not blended rates, regulated or published rate updates, or contractual thresholds. Move that calculation upstream, and the contracts your billing engine can't handle stop being a constraint.
Our customers
Trusted by leading energy retailers
The calculation between the price and the invoice
For complex Commercial and Industrial (C&I) contracts, the number you priced is rarely the number you bill. Trades settle, forecasts become actuals, published rates move and someone has to turn all of that into a billing-ready figure before the invoice goes out.
For most retailers that work still happens in spreadsheets, by hand, every cycle. It is slow, it is hard to audit, and it caps the kind of contracts you can take on.
"In complex C&I portfolios, a small error compounds. A pass-through applied inconsistently, a wrong meter attribute, and profit erodes. Gorilla's pre-billing calculation layer systemises the logic behind the invoice, so outputs are consistent, traceable and aligned to what the contract actually says. That is margin you stop leaking."
Ruben Van den Bossche
CEO, Gorilla
What changes with Gorilla
Stop rebuilding the same calculation every cycle
Configure the logic once, then replay it every period from the latest trade, usage and published-rate inputs, with a full breakdown behind every number. Billing runs that took days finish in minutes.
Reduce disputes, credits and compliance risk
When a customer queries an invoice, retrieve the original instead of rebuilding: trace the number back to its inputs and answer 'where did this come from?' in seconds. Apply rate and regulatory changes once, and they land the same way for every quote.
Launch the products you actually want to sell
Complex terms get scaled back when billing can't process them. Move the calculation upstream and the contract structure stops being the constraint. Offer blended rates, regulated or published rate updates, or contractual thresholds without trimming terms to fit the billing engine.
Scale across markets without adding headcount
Reuse one governed calculation approach across countries and regions. Add local rate sources and rules by configuration, not a new spreadsheet model per market.
Built for the contract clauses that break billing engines
Blended prices
Generate one traceable number from trades and hedges, with residual, indexes, and fees accounted for.
Pass-through updates
Apply published-rate changes without rebuilding the model.
Take-or-pay
Apply threshold logic consistently, every cycle.
The pre-billing calculation layer sits upstream of your billing engine, before invoices are generated.
What this looks like in practice
Replace spreadsheets across four countries
A supplier ran its billing calculations in separate Excel and Python models, one per country. Each run took around eight hours, and a single error meant starting over. Quarter-hourly settlement data was aggregated by hand.
Gorilla systemised the workflow once, then extended it country by country. What used to take days now runs in roughly 30 minutes, with traceable outputs and clear data-quality checks before billing starts.
Gorilla systemised the workflow once, then extended it country by country. What used to take days now runs in roughly 30 minutes, with traceable outputs and clear data-quality checks before billing starts.
Add product structures without rebuilding billing
A supplier had pricing and billing tightly coupled in an incumbent system, which limited the product structures it could sell, such as splitting commodity and PPA line items.
By moving pre-billing calculations upstream, commercial teams could shape the contract to win the deal, while the billing system still received consistent, billing-ready outputs.
By moving pre-billing calculations upstream, commercial teams could shape the contract to win the deal, while the billing system still received consistent, billing-ready outputs.
