Open letterEnergy suppliers' invoicing failures: our letter to suppliers, Ofgem and government.Read and sign
Independent energy bill validation

Powering confidence with accurate energy billing

Optii independently recalculates every charge on every meter and compares it with what your supplier billed. You get evidence when a bill is wrong and confidence when it's right.

Your bills and data

  • Half-hourly data
  • PDF invoices
  • EDI files
  • CSV files
  • Supplier portals
  • Meter reads

Optii and our services

  • Optii
  • OptiiParse
  • OptiiSnap
  • OptiiLive
  • Portfolio Services
  • Bureau Services

Problems we catch

  • Wrong unit rates
  • Network charge errors
  • Duplicate charges
  • Estimated reads
  • Levy and tax errors
  • Out-of-date account data

Plus dozens more checks on every bill

£9,158.55 found on a demo invoice See it rebuilt

Trusted by

What's new

New from Optima

Two new Optii products, a dedicated portfolio service and a partner programme.

OptiiLive Overview screen: files in the window, first-time processing rate, supplier file quality, outstanding discrepancy, files by month and the latest files with their status
OptiiLive, demonstration data

See every file the moment it lands.

OptiiLive puts your whole billing pipeline on one screen: what has arrived, what processed first time, which suppliers send poor-quality files and how much is still outstanding.

  • First-time processing rate, file by file
  • Supplier file quality at a glance
  • Outstanding discrepancy, in pounds
Live webinar

Inside Optii: the live launch webinar

Friday 16 October 2026, 12:30pm (UK time) · Online, on Microsoft Teams

Join our team for a live walkthrough of everything on this page: how Optii recalculates every bill, the new OptiiLive and OptiiSnap products, Portfolio Services and the Partner Programme, and how to prepare for half-hourly settlement. Bring your questions.

Register for the webinar (opens Microsoft Teams in a new tab)

Registration is on Microsoft Teams.

The problem

Energy bills are too complex to take at face value.

Multiple suppliers, thousands of meters, changing tariffs, network charges, levies and flexible wholesale pricing. Somewhere in that detail there could be a charge you shouldn't be paying.

And the rules keep changing. Market-wide half-hourly settlement, network charging reform and shifting levies all change how your bills are calculated.

1 in 3

energy bills we recalculated failed an Optima accuracy check.

The numbers behind the engineMeasured on the platform
£1.8bnof business energy bills recalculated, Jan to Aug 2026
2.7minvoices processed since January 2024
200+documented, versioned API operations for full data access and integration
Under 30Days to go live
Since 1995Independent
The solution

Every bill builds on the last.

We don't just read the bill. We recalculate it against a foundation of your contracts, meters and rates, and every validated bill extends that foundation for the next one.

  1. FoundationYour sites, meters, contracts and rates, set up once and kept up to date as your portfolio changes.
  2. RecalculateEach bill is collected from your suppliers and every charge rebuilt against that foundation and the published rates.
  3. Flag and actDiscrepancies come with the evidence attached, so you can challenge the supplier and recover the money.
  4. Carry forwardValidated reads, consumption and resolved queries become part of the record, so each bill is checked against more history than the last.
  1. Jan–MarValidated
  2. Apr–Jun1 query resolved
  3. Jul–SepValidated
  4. Oct–Dec2 flags
Foundation sites, meters, contracts, rates and every validated bill
Interactive demo

Recalculated, not just checked

Invoice INV-4471-A · Oct–Dec · demonstration data

Recalculates every line against the contract and the published charges.

Charge lineChargedExpectedDifference
Charged£162,701.05
Recalculated–

Not recalculated yet.

What we check

Every line of every bill.

Every bill runs through dozens of validation checks, and every charge is recalculated line by line. Each check is traced back to your contract, your meter data and the published rates, so every flag comes with evidence.

  • Tariff recalculationUnit rates, standing charges, capacity, reactive power, maximum demand and flexible wholesale costs, rebuilt from your contract and the published rates.
  • Network chargesDUoS, TNUoS and BSUoS, checked against the right tariff, banding and loss factors.
  • Levies and taxesRO, FiT, CfD, Capacity Market, AAHEDC, EII and Nuclear RAB levies, plus CCL and VAT against your account history and de minimis rules.
  • Consumption and readsBilled against calculated consumption and half-hourly data, estimated and missing reads, and gas calorific values.
  • Capacity and demandLoad factor, maximum demand, agreed capacity and Triads.
  • Duplicates and payment historyDuplicate bills, periods already paid, reused bill numbers and invoices already in suspense.
  • Cost and period tolerancesExceptional costs, minimum and maximum invoice cost, baselines and billed days.
  • Account and meter set-upUnknown accounts, closed sites, expired contracts, MPAN and MPRN mismatches and unlinked charges.

Electricity half-hourly and non-half-hourlyGas including transportation chargesWater and sewerage including trade effluentPlus other utilities and emerging technologies

What you get

Two ways to work with Optima.

Run bill validation yourself on the Optii platform, have our specialists run it for you, or combine the two.

The Optii platform

Software your team runs: one engine and one set of validated data behind five connected products.

Book a platform demo
Optii home dashboard: year-to-date invoice net cost by utility of 2,248,355 pounds and consumption by utility, with counts of customers, sites and accounts
Your whole portfolio at a glance: cost and consumption by utility, sites and accounts.
Optii Cost and Consumption Trend report: monthly net cost and consumption from September 2023 to June 2026
Cost and consumption trends from validated data. Real Optii screens, demonstration data.
  • OptiiValidate your bills across every site and meter with confidence.
  • OptiiLiveOne screen for complete end-to-end visibility across every file.
  • OptiiParseAI that turns PDF bills into structured data, with 99% extraction accuracy.
  • OptiiSnapActual reads, not estimates, directly into Optii.
  • Carbon reportingScope 1 and 2 emissions reporting from the same validated data.

Managed services

A team of specialists who run the work for you, every step of the way.

Speak to our team
  • Portfolio ServicesYou tell us what changes across your portfolio. Our dedicated team keeps every account, contract, rate and meter up to date, fixing issues before they slow down validation or supplier queries.
  • Bureau ServicesYou send us bills and data. Our team runs collection, validation and supplier queries for you.

Two services, one complete picture

Portfolio Services keeps the record of what you have. Bureau Services checks what you're charged for it. Together they give you the whole picture in Optii.

How Portfolio Services and Bureau Services fit together Your organisation sends portfolio information (sites, meters, contracts and changes) to Portfolio Services, and sends bills and data to Bureau Services. Portfolio Services keeps your portfolio true and Bureau Services validates every bill. The two halves join to form the whole picture in Optii. Portfolio information Bills and data Your organisation Your portfolio Sites and meters Contracts and changes Your bills Supplier invoices Meter and usage data Portfolio Services Keeps your portfolio true Bureau Services Validates every bill The whole picture Portfolio and bills in Optii How Portfolio Services and Bureau Services fit together Your organisation sends portfolio information (sites, meters, contracts and changes) to Portfolio Services, and sends bills and data to Bureau Services. Portfolio Services keeps your portfolio true and Bureau Services validates every bill. The two halves join to form the whole picture in Optii. Portfolio information Bills and data Your organisation Your portfolio Sites and meters Contracts and changes Your bills Supplier invoices Meter and usage data Portfolio Services Keeps your portfolio true Bureau Services Validates every bill The whole picture Portfolio and bills in Optii
Why Optima

Independent by design, technology first: accurate energy data at scale.

We don't sell energy, procurement or brokerage. Our only interest is making sure your bills are accurate. That's 30 years of billing expertise working for you, not for a supplier.

  • Since 1995independent bill validation, with nothing else to sell
  • Every chargerecalculated line by line, across electricity, gas and water
  • ISO 27001certified information security
Who it's for

Built for complex, multi‑site portfolios with significant energy spend.

  • Retail and hospitality
  • Public sector
  • Facilities management
  • Property and housing
  • Energy consultants and TPIs
For TPIs and energy brokers

Earn on every client you introduce.

Partners earn up to 20% of first-year ARR. You procure, we validate, and Optima sells and delivers the service end-to-end.

Become a partner
Book your demo

See Optii check your own bills.

Book a demo and we'll show you Optii working on your own data.

We'll reply within 24 hours. Fields marked * are required. Optima is ISO 27001 certified, and your details are handled under our privacy policy.

FAQ

Frequently asked questions

Can Optima manage multiple sites?

Yes. Optima is built for complex portfolios: many sites, meters and suppliers in one view.

Can you validate flex tariffs?

Yes. We reconcile invoiced rates against your traded tranches, shape, imbalance and pass-through costs.

Can we use our data in other systems?

Yes. More than 200 documented, versioned API operations give you full access to your data, so Optii integrates easily with third-party systems and your own internal data teams.

How do you keep our data secure?

Optima is ISO 27001 certified, the international standard for information security management. Your data is handled under our privacy policy.

Do you replace our energy broker?

No. We validate bills. We don't compete for your energy contract.

How do we get started?

Book a demo. We'll review your portfolio and show you what Optima finds in your own data.