Tech companies in the City of Westminster

Card machines and payment processing for UK and European restaurants, shops and other in-person businesses.

Capital.com is an online trading platform for CFDs and other financial instruments.

Cross-border payments, FX risk management and trade finance for businesses, majority-owned by Santander.

Finastra sells software that banks and lenders use for lending, payments, treasury and core banking.

Bank that lends to growing mid-sized businesses in the UK and US.

Quantitative investment manager that runs systematic trading strategies built on data, research and its own technology platform.

Retirement savings technology platform running workplace pensions and licensing its Keystone tech to providers worldwide.

Parent of WorldRemit and Sendwave, apps for sending money from 50+ countries to 130+ countries.

Buy now pay later and payments app funded partly by advertising, letting shoppers split purchases.

Workplace finance app giving employees earned-wage access, savings, pensions and budgeting tools through their employer.

UK digital bank for mass-affluent savers and borrowers, with a banking-as-a-service tech arm, Monument Technology.

Infrastructure for wealth managers and private banks to give clients access to private markets funds.

Investment platform for UK financial advisers covering account opening, transfers, investment management and drawdown.

Stablecoin payments and treasury platform that lets banks, payment firms and businesses settle money instantly.

Platform that helps businesses and VC funds see currency exposure and automate FX hedging.

Subscription credit service giving UK members interest-free loans for a fixed membership fee instead of interest.

AI platform for financial crime compliance: transaction monitoring, screening, risk scoring and case management.

Programmable banking platform that lets banks and businesses launch accounts, rewards and wealth tools on top of existing core systems; it also powers the HyperJar money app.

Pays online marketplace sellers immediately for their sales instead of making them wait for marketplace payouts.

Savings platform letting people and businesses hold cash across hundreds of accounts from 65+ banks in one place.

AI platform that cleans and enriches bank transaction data for personalisation, lending and customer insight.

Platform that lets institutions invest cash in fixed-term, investment-grade products through one onboarding.

Agentic compliance platform that automates know-your-business checks and continuously monitors business customers for financial services firms.

AI platform that automates document processing, income verification and affordability checks for lenders and brokers.

Ayan offers Shariah-compliant car finance in the UK, buying the car and leasing it to customers for fixed monthly rentals with no interest.

Payments infrastructure that gives banks, EMIs and other licensed financial firms GBP and EUR accounts, virtual IBANs and payment rails through one API.

Open banking API for account-to-account business payments, embedded in platforms such as Xero.

Formerly Ferovinum. Platform giving drinks producers inventory-backed working capital, trading tools and global logistics.

Quantitative research and technology firm that uses machine learning and large datasets to predict movements in global financial markets.

Employee benefits platform for UK employers covering salary sacrifice, pensions, financial coaching and health perks.

Digital homebuying platform that brings mortgage, conveyancing and insurance into one online journey.

Cross-border payments platform for sending money to cards, accounts and wallets in 170+ countries, with APIs for businesses.

Company prepaid cards and spend management software giving staff controlled spending and finance teams oversight.

Issuer processing platform that lets fintechs and banks launch and run debit, credit, prepaid and virtual card programmes globally.

App that helps people pay down credit card debt with lower-cost loans and credit score tools.

London AI cloud company that builds and runs GPU data centres across Europe and the US.

AI voice company making realistic speech, voice cloning and voice agents, with its main hub in London.

Darktrace sells AI-based cybersecurity software that detects and responds to threats across networks, email and cloud.

Builds voice AI agents that answer customer service calls for large companies.

AI platform that reads, negotiates and manages contracts for in-house legal teams.

AI platform running scheduling, HR and payroll for frontline businesses in hospitality, retail and care.

AI procurement platform that runs company buying, supplier onboarding and supplier risk management.

AI that helps IT teams understand, change and migrate complex enterprise systems like SAP.

Multi-model database built for AI agents and applications, available open source and as SurrealDB Cloud.

AI analyst for real estate and real asset investors that speeds up underwriting and reporting.

AI decision platform that models operations at ports, airports, energy and manufacturing sites and recommends or executes actions for operators.

Security and governance platform that lets enterprises discover, monitor and control their AI agents.

Open-source business intelligence tool built on dbt, with an AI analyst that answers data questions.

AI-native procurement platform using AI agents for sourcing, negotiation, intake and spend analytics at large enterprises.

AI recruiting platform whose AI recruiter sources, screens and interviews global talent for companies.

Foresight is a project delivery platform that tracks progress and forecasts risks on large construction and infrastructure projects.

Rezolve AI sells AI-powered product search and conversational commerce software to retailers.

Leah, formerly ContractPodAi, sells an agentic AI platform for legal and enterprise contract work.

AI agent platform (V7 Go) automating document-heavy work in finance, insurance and legal, plus data labelling tools.

Makes an AI fitness mirror that uses computer vision to track form, count reps and coach workouts at home.

AI synthetic audiences that simulate how real customers and populations respond, used for market research.

Shows brands how they appear in ChatGPT, Claude and Gemini answers and how to improve it.

Agentic AI workflows for institutional finance, automating deal screening, credit analysis, IC memos and portfolio monitoring.

Builds AI digital twin software for industrial sites like cement, energy and nuclear plants to run maintenance and safety.

AI tutor for GCSE and A-Level exam prep with adaptive practice questions, essay marking and mock exams.

AI music studio that helps artists generate stems, MIDI, synths and full songs with commercial rights.

HR platform called Bob that helps mid-size and multinational companies manage people, payroll and performance.

Apprenticeship and upskilling programmes that train employees in tech, data and AI skills.

Online marketplace where private sellers list cars and verified dealers bid to buy them.

Online car marketplace where dealers compete with offers to buy or sell your car.

Claranet provides managed network, hosting, cloud, application and cyber security services to businesses in Europe and Brazil.

Builds and runs a full-fibre broadband network selling home and business internet across London.

Supplies official sports data, betting technology and data-driven advertising to sports leagues, sportsbooks and media companies.

MUBI is a curated film streaming service that also produces and distributes films.

Commerce operating system for brands covering cross-border shipping, returns, tax, checkout and inventory.

AI procurement platform that helps finance teams buy and negotiate software and other spend, and has acquired Vendr.

Platform that turns food brands into national franchises through a network of 400+ delivery kitchens and high street restaurants, providing the systems, support and distribution to scale them.

Publishes indie video games, including Balatro and Abiotic Factor, across PC, console and mobile.

Premium ticketing, hospitality and travel platform for sport, music and culture events across the UK and Europe.

Acquires and operates B2B software tools for ecommerce merchants, adding AI features across its portfolio.

Cybersecurity platform for email authentication (DMARC, BIMI), brand impersonation and certificate protection.

Digital freight forwarder and supply chain platform that books, tracks and manages international shipments for brands.

Scans building interiors with LiDAR and AI to produce verified floor plans, measured surveys and digital twins for real estate (formerly Pupil).

Online marketplace that matches people with local service professionals across more than 1,500 categories.

givestar is a fundraising platform that charities use for digital, event and contactless donations and supporter engagement.

Platform for corporate giving and nonprofit verification used by brands like Google, Atlassian and Canva. Formerly Percent.

Security platform that links alerts across a customer's existing tools into cases, with AI triage and a managed 24/7 SOC under human oversight.

Pre-employment screening platform running background checks, references and right-to-work checks in 150+ countries.

what3words divides the world into 3m squares and gives each a unique three-word address, used in its app and API.

Platform that handles payments, logistics, compliance and storefronts for consumer brands selling into China.

Digital-first clinic offering virtual GP, mental health and extended care services to patients across Europe.

Clinical-stage biotech developing next-generation oral and injectable medicines for obesity and cardiometabolic disease.

Digital health platform for remote patient monitoring, clinical research and disease management apps.

AI platform that sources, trains and relocates international nurses and doctors for hospitals in the UK, Europe and Gulf.

Compass Pathways is developing COMP360 psilocybin treatment for treatment-resistant depression.

Marketplace and booking infrastructure connecting patients, payers and providers with imaging centres in the UK and US.

Cloud platform that connects operating rooms so surgeons can collaborate remotely and hospitals can analyse surgical video and data.

Online dermatology service that prescribes personalised skincare treatments for acne and ageing, delivered by monthly subscription.

At-home hormone and fertility testing with specialist care for women.

London oncology drug developer that in-licenses cancer assets and funds them through clinical trials.

Provides employers with reproductive health benefits covering fertility, menopause, men's health and neurodiversity, including clinical consultations, testing and treatment financing.

Telehealth platform connecting people with skin clinicians for personalised, medical grade skincare.

Digital mental health platform offering young people online counselling, coaching and peer support, delivered under contracts with health systems and US states.

Federated trusted research environment that lets researchers analyse sensitive health and genomic data without moving it.

Medefer runs remote consultant-led outpatient care for NHS trusts and private patients, coordinating any in-person tests through partner sites.

Tangram Therapeutics combines computational drug discovery with biology to develop RNAi medicines, led by TGM-312 for MASH liver disease.

Toothfairy is a dental app that connects patients with UK-registered dentists for remote consultations, aligners and treatment plans.

Operating system software that utilities use to run billing, customer service and energy assets.

Renewable-focused gas and electricity supplier and Britain's largest household energy supplier.

Zenobe builds and runs grid-scale battery storage and provides charging, batteries and software to electrify bus and truck fleets.

UCL spinout using magnetic fields and control software to make lithium-ion batteries charge faster and last longer.

Builds liquid air energy storage plants that store renewable power for long periods and release it to the grid.

Smart home EV chargers and app that charge cars when power is cheapest and greenest.

Runs a blockchain built for stablecoin payments, including zero-fee USDT transfers.

Institutional crypto custody, collateral and off-exchange settlement (ClearLoop) provider.

Stablecoin payment infrastructure for converting and moving money between fiat and stablecoins across 70+ countries.

Risk ratings and monitoring of crypto exchanges, custodians and lenders so institutions can manage counterparty exposure.

London research and development hub building core protocol and apps on the Tezos blockchain.

Builds trapped-ion quantum computers and quantum software, formed from Cambridge Quantum and Honeywell Quantum Solutions.

Nasdaq-listed company selling quantum-safe encryption and post-quantum migration tools to governments, defence and telecoms.

Builds quantum computing apps for music, games and media, including the consumer game Quantum Backrooms.

Builds photonic quantum computers that run in normal data centres alongside AI and HPC systems.

Munich-headquartered defence AI company building strike drones, underwater systems and battlefield software, with a London office.

Defence software (Cobalt) that lets operators control mixed fleets of drones, robots and sensors from one platform.

Refute is an AI platform that detects coordinated online disinformation campaigns early and recommends how to respond.

Makes NightFighter radio frequency jamming and electronic warfare systems that detect and bring down hostile drones.

Foundational runs automated satellite laser ranging ground stations, retroreflectors and a data platform to track satellites and debris precisely.

V-Nova develops and licenses video compression technology, including the MPEG-5 LCEVC standard, for streaming services, broadcasters and device makers.