Fluxa, in full. What it is, what it ships, what it costs.

In one paragraph

The fastest way to understand Fluxa, before the detail.

Fluxa Ltd is a UK Payment Facilitator as a Service (PFaaS) processing Visa and Mastercard transactions for UK businesses under the FCA authorisation of a payments partner. The pricing is flat (1.8% for UK businesses), the payment lifecycle is exposed as six explicit states, the ledger is double-entry, and merchant support is direct from the team. Fluxa is an independent UK company, pre-launch as of May 2026, onboarding its founding cohort of first merchants.

What Fluxa is

A UK card payment platform with an unusual operating model.

Fluxa is a payment processor for UK businesses, designed for online subscription, B2B SaaS and digital-first merchants. It operates the same kind of service that Stripe, Adyen and Checkout.com provide: hosted checkout, embedded SDK, recurring billing, dashboard and API. The processing runs on top of an FCA-authorised payments partner that holds cardholder funds and settles directly to the merchant’s nominated bank account.

The unusual part is the operating model. Fluxa is a UK company, bootstrapped, with a small core team supported by a production AI workforce. Pricing is one published percentage per transaction, with no surcharges, overlays, or per-card-type variation. Merchants get support direct from the team from day one. The platform is built end to end in the UK and hosted in the UK.

The thesis

UK card processing is overpriced for the value delivered. Fluxa exists to close that gap.

Stripe’s UK headline rate is 1.5% + 20p. After corporate-card surcharges, cross-border uplifts, FX, and the long tail of small fees, typical effective rates for UK B2B SaaS land between 2.3% and 2.8%. Adyen and Worldpay are competitive on enterprise volumes but quote-only and slow to onboard. Square and SumUp serve the SMB segment competitively at the surface but lack the depth and developer focus needed for online subscription, B2B SaaS, or platform-led commerce. Most UK businesses accept this because the alternative looks worse: bank merchant accounts are even slower, even more opaque.

Stripe has won on developer experience. The cost has come with it. Our thesis is that a third option exists: a flat published rate, full payment-state visibility, double-entry ledger integrity, and a direct support line into the team, at a price below Stripe’s effective UK rate. The technical groundwork is in place. The economics work because Fluxa runs lean by design, and our margin above payments partner cost is published, not blended into a headline rate.

Side-by-side comparisons with Stripe, Square, GoCardless, PayPal Business, Teya, Adyen and Worldpay are on the compare page, with sources cited and access dates published.

The team

Fluxa is a small UK company with a deliberately lean operating model. A core team builds and runs the platform; a production AI workforce extends the reach.

Our core team handles product, engineering, design, brand, operations and compliance. Day-to-day this means writing the code, designing the merchant experience, onboarding new businesses, completing KYB and KYC checks, screening against sanctions lists, and acting as the regulatory liaison with our payments partner. We work in the open and the build is documented on the changelog.

Alongside the core team, Fluxa runs a production AI workforce. Tom Harris is the 24/7 merchant support and advocacy agent and lives inside the dashboard. The agents are real production systems with named roles and disclosed identities, not chatbots, and not a substitute for human contact when merchants need it.

Founder enquiries: paul@fluxapay.co.uk. Operations and compliance: charlotte@fluxapay.co.uk. General: support@fluxapay.co.uk.

What we ship

The product surface, line by line.

• Hosted checkout at pay.fluxapay.co.uk · full UI hosted by Fluxa, merchant branding configurable, SAQ-A compliant.
• Embedded checkout SDK · cross-origin iframe drops into the merchant page, card data flows direct to the payments partner.
• Card rails · Visa and Mastercard, with Apple Pay and Google Pay tokens. Amex and PayPal are not supported at launch.
• Six-state payment lifecycle visible to merchants: PAYMENT_RECEIVED, CAPTURED, SETTLING, SETTLED, REFUNDED, FAILED. SETTLING → SETTLED is direct to the merchant’s nominated GBP account; T+1 settlement is the aim, subject to approval and risk review.
• Double-entry ledger running independently of the state machine. Discrepancies halt processing on the affected transaction.
• Recurring billing engine with subscription primitives, proration, retries, dunning and customer portal.
• Pre-dispute evidence capture · 3DS outcome, AVS/CVV, IP, device fingerprint and timestamps recorded on every transaction.
• Nineteen anomaly detectors monitoring failure spikes, volume drops, settlement delays and refund patterns.
• Verified Commercial Identity (VCI) · Ed25519-signed PDF documents proving processing history for banks and lenders.
• Real-time merchant dashboard with SSE streaming, IP allowlisting, CSV exports and double-entry ledger views.
• API and webhook system with HMAC-SHA256 signing, idempotency keys and atomic state transitions.
• Direct support from the team via email, phone or Slack Connect. No tier system, no triage queue.

The economics

What merchants pay, in full, with nothing held back.

The pricing is published on the pricing page and matches the merchant agreement exactly. One flat rate applies to UK businesses, plus a custom volume rate above £500k per month.

Beyond the headline rate, Fluxa charges nothing. No per-transaction fixed fee. No monthly minimum. No setup fee. No cross-border or FX uplift. No corporate-card or commercial-card surcharge. No refund fee. No Fluxa-side chargeback fee. Card scheme chargeback fees (typically £15) are passed through at cost on lost chargebacks. Everything else is the headline rate, end of list.

How it is built

Architecture built on the principle that payment processing is too important to be opaque.

State machine

Every payment moves through six explicit, atomic states. Transitions are guarded by database WHERE-clause locks to prevent duplicate postings under concurrent load.

Double-entry ledger

Financial movements record as paired debit and credit postings, running independently of the state machine. The two systems check each other; discrepancies halt processing on the affected transaction.

UK hosting

Application servers, database, logs and backups are UK-based. No cross-border data flows for Fluxa-controlled data.

PCI DSS SAQ-A scope

The lowest PCI scope, applicable because Fluxa never receives full PAN. Tokenisation happens at the payments partner under their PCI Level 1 attestation.

Test coverage

37 test suites covering anomaly detection, payment orchestration, ledger integrity, state transitions, recurring billing, and the public API surface.

Security hardening

SSRF hardening on every outbound webhook delivery. 3DS2 / PSD2 SCA enforced on every eligible transaction; liability shift preserved on successful authentication.

Full technical disclosure on the security page. API design documented at developers.

Regulation and compliance

The regulatory frameworks Fluxa operates under, named and accurate.

FCA authorisation

Via payments partner (Payment Institution permissions). The payments partner is the FCA-authorised entity for UK card processing; Fluxa operates under their authorisation as a payment facilitator.

PCI DSS v4.0

Self-Assessment Questionnaire A (SAQ-A). Annual self-assessment. The lowest possible PCI scope, applicable because Fluxa never stores or transmits full card data.

UK GDPR and DPA 2018

Full compliance. ICO registration on file. Documented subject access request process. Retention schedules published on the privacy notice.

Card scheme rules

Visa Core Rules and Mastercard Rules. 3DS2 enforced on every eligible transaction. Chargeback handling per scheme rules.

Money Laundering Regulations 2017

KYB and ultimate beneficial owner verification at onboarding. Daily sanctions screening against OFSI, OFAC and Open Sanctions databases.

English law

Merchant agreement governed by English law. Exclusive jurisdiction of the courts of England and Wales. Full terms of service.

Companies House

Fluxa Ltd, registered England and Wales, company number 17028144.

Trade mark

Fluxa is a UK Registered Trade Mark, UK00004340109, held by Fluxa Ltd.

The founding cohort

The first UK merchants going live on Fluxa. Every merchant pays 1.8% flat; founding merchants also get hands-on onboarding and a direct say in the roadmap.

• 1.8% flat rate, for UK businesses, written into the merchant agreement. No unilateral rate changes.
• Direct support from the team via Slack Connect, email and phone. No tier system, no triage queue.
• Roadmap influence · early-merchant feedback directly shapes the product roadmap for the first eighteen months.
• Public reference status is optional. Many founding merchants will prefer to stay private; that is fine.
• No setup fees, no monthly minimums, no long-term commitment. Thirty days’ notice to terminate at any time.

Every UK merchant onboards at 1.8% flat. The rate is written into the merchant agreement and held there, with thirty days’ notice of any change to published pricing.

Founding onboarding is paced so the team can give each merchant close attention during go-live. The pace is about support quality, not a pricing gate; the 1.8% flat rate is the same for UK businesses.

Coverage and references

External coverage and where to find more.

Fluxa was profiled by FinTech Futures in 2026, ahead of launch. The piece focused on the operating thesis (flat pricing, small founder-led team, AI workforce) and the architecture (state machine, double-entry ledger, Verified Commercial Identity).

The build is documented in public on the changelog and through build-in-public posts on X (@fluxapay) and LinkedIn.

Press enquiries to press@fluxapay.co.uk. Full press kit on the press page.