Software
API Development & Integration in London
Connecting the tools you already use, and building custom APIs when you need your own systems to expose data securely to others.
Quick Answer
ZAVYANS provides API Development & Integration for businesses in London, remotely from our offices in Islamabad and Arlington, Virginia, with calls in your business hours. The work typically covers webhook & automation setup, custom API development and legacy system integration, planned around local rules from the start, with reporting and invoicing in GBP.
Why London businesses work with us
Calls in UK hours (GMT/BST) and written weekly reporting, so you always know what was done and what it produced
Work researched around London's real markets: the City and Canary Wharf, Shoreditch and King's Cross tech, Harley Street healthcare and West End retail
One team running marketing, automation and software, instead of several London suppliers who don't talk to each other
Reporting and invoicing in GBP, with no central-London office overhead built into your fees
Why your systems need to talk to each other
Most businesses run several separate tools, a CRM, a website, an accounting system, a booking platform, that do not talk to each other by default. Staff end up copying data between them by hand, which wastes time and causes errors. API development and integration connects these systems so data flows automatically.
We build integrations between the tools you already use, and custom APIs when you need your own systems to expose data to others.
What's included
Webhook and automation setup
Triggering actions automatically when something happens in another system.
Custom API development
Building APIs that let your own systems, or partners, access your data securely.
Legacy system integration
Connecting older systems that were not built to work with modern tools.
API security
Making sure data shared between systems is properly authenticated and protected.
Third-party integrations
Connecting your CRM, payment gateway, accounting or booking tools together.
Documentation and support
Clear documentation so your team, or partners, can actually use what is built.
Doing business in London
London is not one market but several sitting a few miles apart. The City and Canary Wharf are dominated by financial and professional services firms that expect polished, compliance-aware work. Shoreditch, Old Street and King's Cross hold one of Europe's largest tech and startup scenes, where speed matters more than polish. Marylebone and Harley Street are the centre of UK private healthcare, while the West End, Mayfair and Knightsbridge carry retail, hospitality and luxury brands. Across Greater London's 32 boroughs and nearly 9 million people, thousands of SMEs, trades and local services compete street by street. We plan every engagement around which of these Londons you are actually selling to.
We work with London businesses remotely from Islamabad, which is four to five hours ahead of the UK, so our working day overlaps your morning and early afternoon. Calls are scheduled in UK hours, reporting and invoicing are in GBP, and there is no London office overhead built into our fees.
API Development & Integration rules in the UK
Websites and apps must handle personal data under UK GDPR and cookies under PECR, and public-sector sites must also meet accessibility regulations.
What's different about API Development & Integration in the UK
UK websites need to be fast, accessible and clear about cookies and personal data.
- WCAG 2.2 AA accessibility built in
- Payments through Stripe, PayPal, GoCardless or Worldpay, with VAT handled
- Cookie consent that meets UK GDPR and PECR
Integration work that pays for itself
The value of integration work is usually easiest to see in hours saved: an order that used to be re-typed into three systems now flows automatically. We scope integration projects around where your team is currently doing the most manual, repetitive work.
Building for London users
London customers expect fast, polished digital experiences, and B2B buyers often judge a supplier by its website before they ever speak to it. For API Development & Integration, we build for UK users from the start: UK spelling and formats for dates, phone numbers, prices and postcodes, cookie consent that meets PECR, accessibility against WCAG 2.2, and performance tuned for UK visitors. Larger London organisations and public bodies will also expect accessibility and data protection to be documented, so we build that in rather than adding it at the end.
Who we work with in London
- Startups and scale-ups: In Shoreditch, King's Cross and Canary Wharf, shipping quickly without cutting corners.
- Professional and financial services: Credible, compliant sites and client portals.
- Retail and D2C brands: Selling online across the UK from a London base.
Reaching South Asian audiences in London
London has some of the UK's largest South Asian communities, in areas such as Southall, Ilford, East Ham, Whitechapel and Tooting. Our team works in English and Urdu, which helps when a campaign, landing page or customer conversation needs to reach Urdu-speaking audiences as well as the wider London market.
Results from real client work
Engagements for clients in the USA and Pakistan. Client names are withheld and figures are rounded ranges.
Case study · 2025
ZAVYANS grew real estate developers in Lahore, Islamabad, Rawalpindi and the Galyat from ~50-150 leads a month to 600+, with 20-50% lower cost per lead (2025).
Read the case study →
Case study · 2025
ZAVYANS grew a dental clinic in Islamabad and Rawalpindi from ~10-30 to 60-100 patient enquiries a month, with 20-50% lower cost per enquiry, in 3-6 months (2025).
Read the case study →
Areas of London we cover
The City of London
The Square Mile: banks, insurers, law firms and professional services.
Canary Wharf
Financial services, fintech and large corporate headquarters.
Shoreditch and Old Street
Startups, agencies and the 'Silicon Roundabout' tech scene.
King's Cross
Tech, life sciences and major offices, including Google and Meta.
Westminster and the West End
Retail, hospitality, theatre, media and public affairs.
Marylebone and Harley Street
Private medical, dental and aesthetics clinics.
Mayfair and Knightsbridge
Luxury retail, private wealth and high-end property.
Soho
Media, film and post-production, restaurants and creative studios.
Stratford and East London
Fast-growing residential and business districts around the Olympic Park.
Croydon
South London's largest business centre and a growing tech hub.
We also work with businesses across outer London and the commuter belt, including Watford, Reading, Slough, Kingston upon Thames, Bromley and towns throughout Surrey, Kent, Essex and Hertfordshire. We work remotely, so where you are based doesn't change how the engagement runs.
Who we help
SaaS companies
Building APIs that let customers or partners integrate with your product.
E-commerce
Connecting stores, payment gateways and inventory systems.
Real estate agencies
Connecting CRM, listings and booking systems.
Healthcare providers
Connecting booking, records and billing systems.
How we work
- Step 1
Audit
We review what you have today against the result you actually want.
- Step 2
Build
Tracking, creative, pages or systems go in before spend or launch.
- Step 3
Launch and test
Work goes live and is tested in rounds with a clear weekly read-out.
- Step 4
Grow
Budget and effort follow what is actually producing results.
Frequently asked questions
Do you have an office in London?
Not a physical office. We work with London businesses remotely, with calls in UK hours (GMT/BST), written weekly reporting and invoicing in GBP. Not paying for a London office keeps our fees lower than many local agencies.
Do you provide documentation for our team?
Yes, clear documentation is part of every project so your team can maintain and extend it.
How do you keep integrated data secure?
Through proper authentication and access controls on every API connection we build.
Why choose ZAVYANS for API development?
We scope integration work around where your team is currently doing the most manual, repetitive data entry, so the value is measurable in time saved.
What rules apply to API Development & Integration in the UK?
Websites and apps must handle personal data under UK GDPR and cookies under PECR, and public-sector sites must also meet accessibility regulations. We plan the work with this in mind, and you approve anything customer-facing before it goes live.
Can you connect tools we already use?
Yes, connecting existing tools like your CRM, payment gateway or accounting software is the most common request.
Do you build custom APIs from scratch?
Yes, when you need your own systems to expose data securely to another system or partner.
Which cities in the UK do you work with?
Businesses anywhere in the UK, including London, Manchester, Birmingham, Leeds, Glasgow, Liverpool, Edinburgh, Bristol, Sheffield and Newcastle. Campaigns and content can be targeted to specific cities or regions.
Which countries do you work in?
We work with clients across Pakistan, the United States, the United Kingdom, Canada, Australia, the UAE and Saudi Arabia.
What do you need from me to start?
A list of the systems you want connected and the manual process you are trying to eliminate.
Can you integrate with older, legacy systems?
Yes, we work with legacy systems, though the approach depends on what access they allow.
Do you build to UK accessibility and cookie rules?
Yes. We build to WCAG 2.2 and set up cookie consent that meets PECR and UK GDPR, so analytics and marketing tags only run with consent.
Can you work alongside our in-house London team?
Yes. We often work with in-house product, marketing or engineering teams, using shared repositories and project boards, with regular calls in UK hours.
Which areas of London do you cover?
All of London and the surrounding area, including The City of London, Canary Wharf, Shoreditch and Old Street, King's Cross, Westminster and the West End. We also work with businesses across outer London and the commuter belt, including Watford, Reading, Slough, Kingston upon Thames, Bromley and towns throughout Surrey, Kent, Essex and Hertfordshire.
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Let's build something
Ready to grow with API Development & Integration in London?
Tell us what you're trying to grow. We'll come back with a plan, not a sales pitch.
or email info@zavyans.com
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