Custom Development
API integration services for UK businesses
Connect your tools so information moves on its own, with logging and alerts so you know it is working. A fixed written quote after a free call.
In short
API integration connects your business systems so data moves between them without anyone re-keying it. APPS 365 is a UK company that builds and supports custom integrations between CRM, accounting, payment, e-commerce and Microsoft 365 systems, with logging and alerts, and a fixed written quote before work starts.
Signs your systems need connecting
When tools do not talk to each other, people become the connection. That is slow, and it is where mistakes creep in.
Staff re-key the same data into two or three systems.
An integration moves the record when it changes, so each system holds the same details without anyone typing them again.
Your tools have no obvious way to talk to each other.
We connect them through their APIs, or through a small service in the middle where there is no direct route.
DIY automations break, and nobody notices until it matters.
A custom integration retries, logs what happened and alerts someone when it needs a person.
You cannot tell whether yesterday's orders reached your accounts.
Logging shows what moved, when it moved and what failed, so problems can be found and fixed.
You worry about what happens when a supplier changes its API.
Monitoring picks up failures, and looking after the integration can be agreed in your quote.
What you get from a custom integration
Connected to what you already use
CRM, accounting, payments, e-commerce and Microsoft 365, without replacing the systems your staff know.
One clear source for each record
We agree which system holds the master copy of each record, so updates do not overwrite each other.
Only the access it needs
Each connection gets the least access that does the job, with keys kept out of the code and easy to change.
Monitoring and alerts
You can see that it is working, and someone is told when it is not.
Failures handled properly
Retries, queues and clear error handling are designed to stop a short outage at one supplier from losing your data.
Custom APIs when you need one
If your own system has no API, we can build one, with documentation so others can connect to it.
What is included
Exactly what you get is set out in your written quote. A typical integration covers:
- A map of your systems, your data and which system owns each record
- Field mapping, and rules for what happens when records conflict
- The build, using each system's API or webhooks
- Secure handling of keys, limited access and logging
- Testing against supplier sandboxes where they exist, then real examples
- Monitoring and alerts for failures
- Documentation, handover and agreed support
Common integrations
Most modern business software publishes an API. We check yours before we quote, so you know what is possible.
| Connection | What it can do |
|---|---|
| CRM to accounting software | New customers and invoices appear in your accounts without re-keying |
| Payments to accounts | Payments and refunds reach your accounting system as they happen |
| E-commerce to stock and accounts | Orders, stock levels and customer details stay in step |
| CRM to Microsoft 365 | Contacts, meetings and documents line up with Outlook, Teams and SharePoint |
| Your own system to Microsoft Graph | Your software reads or updates Microsoft 365 data, with permissions your administrator approves |
Integration, automation tool or custom API?
These overlap, and the simplest one that does the job is usually the right answer. We will tell you if an automation tool would be enough.
| What it is | Good for | |
|---|---|---|
| Automation tool | Steps set up in Power Automate, Zapier or similar | Simple, low-risk jobs between popular tools |
| Custom integration | A connection between systems, built in code | Higher volumes, important data and rules a tool cannot express |
| Custom API | A new interface to your own system | Software with no API, or data you want to share with partners |
Microsoft 365 and Microsoft Graph
Microsoft Graph is Microsoft's API for Microsoft 365 data: users, mail, calendars, Teams, SharePoint and OneDrive. It lets outside systems work with Microsoft 365 properly, with permissions an administrator approves. We publish our own SharePoint and Microsoft 365 software on Microsoft Marketplace, so we build on this platform every day.
Graph permissions can reach widely across an organisation, so we ask for only what the job needs and explain each one, so your IT lead can make an informed decision.
How an integration project works
- 1
Free call
Tell us what you want to connect and what keeps going wrong. No obligation.
- 2
Written quote
We check the APIs involved, then you get a fixed price, the scope and the timetable in writing before any work starts.
- 3
Map the data
We map the fields, agree which system holds the master copy and decide what happens on a conflict.
- 4
Build and test
We build the connection with error handling and logging, then test it against sandboxes and real examples.
- 5
Launch and monitor
We go live with alerts in place, and can look after it as APIs change, on the terms in your quote.
Connected software of our own
These are our own products, not client work. We do not have client integration examples to show here yet, so judge us by what we have built and published ourselves.
Pricing guide
Each integration is priced after a free call, with a written fixed quote before work starts. The price depends on how many systems are involved, the quality of their APIs, how much data has to move and how failures must be handled. Monitoring and support terms are set out in your quote.
- Priced after a free call
- Fixed written quote before work starts
- Monitoring and support terms in your quote
Why APPS 365
UK-based
APPS 365 LTD is registered in England and Wales, with a registered office in London.
Microsoft ecosystem specialists
We publish SharePoint and Microsoft 365 apps on Microsoft Marketplace, so we build on this platform every day.
We ship our own products
Apps, games and SaaS platforms of our own, live for anyone to try. ComponentSource Top 100 Publisher 2022, 2023 and 2025.
A fixed quote first
A free call, then a written quote before any work starts, so you know the cost and scope.
Want AI in the workflow as well as the connections? apps365.ai, our AI building arm, covers AI automation.
AI automation on apps365.aiFrequently asked questions
How much does API integration cost?
It depends on the systems involved, so each integration is priced after a free call, with a written fixed quote before work starts. Well-documented APIs and simple rules cost less than old systems and complicated matching rules. Any monitoring and support costs are shown in your quote.
How long does an integration take?
It depends on the systems and the data, so the timetable is agreed in your written quote. Connecting one clear flow first, then adding to it, is usually the quickest way to get something useful running.
What is the difference between API integration and automation?
Integration connects systems so they can exchange data, and automation is the work you then have happen without a person. The two overlap, and many jobs need both. A tool such as Power Automate can be enough for simple cases, and we will say so if it is.
Can you connect my CRM to Microsoft 365?
Yes, in most cases, as long as your CRM has an API, which most modern ones do. We use Microsoft Graph on the Microsoft 365 side, with permissions your administrator approves. We check your specific CRM before we quote.
Which systems can you connect?
We can connect most systems that publish an API, for example CRMs such as HubSpot or Salesforce, accounting tools such as Xero or Sage, Shopify shops, Stripe payments and Microsoft 365. Older systems without an API can sometimes be connected through file exports or their database.
What happens when a supplier changes its API?
The integration can stop working, which is why monitoring and alerts matter. Suppliers usually announce changes in advance, and looking after the integration through those changes can be agreed in your quote.
Is our data secure, and what about UK GDPR?
We design for it by moving only the data the job needs, limiting each connection's access, keeping keys out of the code and logging activity. Where data passes through and is stored is agreed in writing in your quote. You remain responsible for your data as controller.
Will we depend on you for support?
Code ownership, documentation and handover are agreed in writing in your quote, so you can settle this before work starts. Tell us on the call if you want your own staff to take the integration on later.
Tell us what you want to connect
A free 30-minute call, then a fixed written quote. No obligation.
