Most growing UK businesses end up running a dozen or more specialised tools: a CRM, accounting software, an ecommerce platform, payroll, a payment processor, a help desk, maybe an older ERP nobody wants to touch. None of them talk to each other properly. So someone exports a spreadsheet from Xero, reformats it, and pastes it into Salesforce. Every week. Orders get keyed in twice. A customer’s address is right in one system and wrong in two others.
That is the problem API integration solves: getting your systems to pass data between themselves automatically and reliably, so your team stops being the integration layer. The honest question is not whether to integrate, but how. For a few simple connections between mainstream cloud tools, a low-code platform is often the sensible answer. When the integrations carry real business logic, touch a legacy system, or run at volume, a build that fits your operations exactly tends to be the better long-term call. We help you work out which side of that line you are on, and we will tell you plainly when an off-the-shelf tool is enough.
Where off-the-shelf integration tools fall short
Platforms like Zapier, Make and the unified-API services are genuinely useful, and there is no point pretending otherwise. But for a business with real operational complexity, the same problems keep surfacing:
- Opinionated workflows. The platform has its own idea of how a process should run. Custom commission structures, multi-step approval chains and industry-specific rules either don’t fit or get bolted on awkwardly.
- Shallow connectors. Pre-built connectors cover the popular fields and stop there. Anything proprietary, or any real data transformation, lands back on you.
- Legacy systems left out. Connectors assume a modern REST API. Older ERPs, manufacturing equipment, EDI supplier links and in-house tools often don’t have one, so there is simply nothing to plug in.
- Pricing that scales the wrong way. Per-task, per-transaction and per-connected-account models look cheap on the starter tier, then climb steeply. Migration, custom connectors, SSO, audit logs and premium support are frequently extra.
- Silent failures. Hit a rate limit, miss a webhook, or have a vendor deprecate an endpoint, and a basic integration can fail without anyone noticing for days, quietly corrupting data.
- Lock-in. Years of integration logic ends up embedded in a proprietary platform. Moving off it later is expensive, and some platforms charge to export your own data.
So you end up with workarounds, frustrated staff, and a nagging sense that the tooling is fragile. A custom integration avoids most of that, because it is designed around what your business actually does and the systems you actually run.
What ByteGears builds instead
We build the integration layer your business needs and hand it to you to own. No per-seat licence, no per-transaction meter, and no question over where your data sits under UK law.
Designed around your process. We map your real workflows, including the undocumented spreadsheet steps, before anyone writes code. The integration fits your operations rather than forcing you to rework them.
Awkward systems are the point. Joining things that were never meant to talk to each other is the job. We write the adapters and transformation layers for SOAP, XML, flat-file exports and bespoke endpoints, so a legacy ERP or an in-house tool joins in cleanly.
Built to survive third-party APIs. APIs change, throttle and break. We build retry and back-off logic, idempotency handling for duplicate or out-of-order webhooks, and monitoring that alerts a person when a sync fails rather than letting it fail in silence.
You own it outright. One build replaces a stack of subscriptions and stays yours. When your needs change, the integration changes, with no vendor to negotiate with.
Built to UK standards. We are a UK team and build with UK GDPR and ICO guidance in mind, plus whatever else applies in your sector. UK hosting is available where data residency matters.
Room to grow. The architecture is modular, so adding the next system later is a known piece of work rather than a rebuild.
What the integrations typically include
Every build is different, but most cover some mix of the following:
An integration engine — the core scheduler, API client and webhook handler that does the actual work of moving data between systems.
A transformation layer that maps fields between systems and reconciles the fact that every API describes a “customer” or an “order” slightly differently.
Two-way sync with configurable triggers and conflict handling, so a change in one system reaches the others without overwriting something it shouldn’t.
A business logic layer that runs your own operational rules, conditional routing and approval steps inside the integration.
Robust error handling that retries what it can, quarantines what it can’t, and escalates to an administrator with enough detail to act on.
Role-based access so people see only the data and functions they should.
An immutable audit trail recording every data movement, who triggered it and when, exportable when a regulator or auditor asks.
A monitoring dashboard showing live integration status, execution history and failure rates, with reporting views tailored to different roles.
Scheduled batch jobs for heavy operations timed to run outside business hours, alongside real-time, event-driven sync where the process demands it.
How a project runs
We deliberately start small and prove value before expanding.
Discovery and planning (around 2 to 4 weeks). We sit down with your stakeholders and technical people to document the systems involved, the data each holds, the business rules in play, and the failure points to design around. Dirty source data and undocumented workflows get flagged here, not three months in.
Phase 1 / MVP (roughly 6 to 12 weeks). We build the two or three highest-impact integrations first — often CRM to accounting, or payments to accounting — with reliable sync, sensible error alerts and a basic audit trail. You get something working and useful early.
Phase 2 expansion (typically 8 to 12 weeks after Phase 1). With Phase 1 lessons in hand, we add further integrations, conditional and approval workflows, real-time sync for the critical paths, and full audit logging.
Testing, parallel run and go-live. Security testing, performance checks under realistic load, and user acceptance testing. For anything replacing an existing process we run in parallel before cutover, rather than switching everything overnight.
Training and support. Documentation and hands-on sessions for each role, then flexible support for maintenance and for adding new systems as your stack evolves.
A simple two-or-three-system build wraps up inside a few months. A larger integration hub with complex logic and legacy systems is a four-to-six-month effort. Discovery gives you the firm number.
What it costs, and what you own
Custom development is a larger upfront cost than a subscription, so it is worth being straight about the trade-off.
A subscription platform is cheap to start and easy to underestimate. The headline price grows with users, tasks, transactions or connected accounts, and the things that matter — migration and onboarding, custom connectors, SSO, audit logs, SLA-backed support — are routinely priced separately. For a business running several integrations at volume, those costs compound.
A custom build is a fixed upfront investment followed by a predictable annual figure for maintenance. There is no per-transaction meter, no renegotiation at renewal, and no surprise bill in a busy month. Over a two-to-three-year horizon, a business with real integration complexity usually comes out ahead — and ends up owning the logic outright, with no platform to be locked into.
There is no single price, because it depends entirely on how many systems are involved, how modern their APIs are, and how much business logic sits in the workflows. The free consultation gives you a straight comparison for your situation, not a generic figure.
When a build makes sense, and when it doesn’t
We would rather you spend the money well, so here is the honest version.
A low-code platform is usually enough when you are connecting a handful of mainstream SaaS tools, the data is simple field mapping, there is no legacy system in the mix, and an hourly or daily batch sync is fine. If that describes you, we will say so.
A custom build earns its keep when you have five or more systems with overlapping or conflicting logic, at least one legacy or in-house system with no decent API, conditional workflows and approval chains, real-time sync the business genuinely depends on, compliance or audit requirements that off-the-shelf tools don’t cover, or per-transaction pricing that has started to bite at scale.
It is often not all-or-nothing. A sensible answer is frequently a hybrid: a low-code tool for the simple connections, a custom layer for the complex ones. We are happy to design it that way.
Where this gets used
Custom API work shows up across most sectors. A few common patterns:
Ecommerce and retail. Keeping Shopify or WooCommerce, an inventory system, the POS and accounting in step, so stock levels and orders stay accurate across channels. Per-transaction pricing is also where high-volume retailers tend to outgrow off-the-shelf tools.
Financial services and accounting. Bank feeds reconciled into the GL, order-to-invoice-to-payment automated end to end, and transaction data routed into regulatory reporting. Rigid approval hierarchies are the usual reason SaaS platforms don’t fit here.
Professional services and agencies. Project management, timesheets, billing and accounting joined into a project-to-bill flow, including non-standard models like retainers and hybrid billing that generic tools handle badly.
Manufacturing and supply chain. ERP, inventory and shop-floor systems synced for production planning, with custom bridges to proprietary equipment that has no modern API.
Healthcare. Patient management linked to lab, pharmacy and billing systems, built around the data standards and compliance requirements the sector demands.
HR and payroll. Onboarding wired across HRIS, payroll, benefits and IT provisioning, handling the custom compensation and approval structures that off-the-shelf HR tools struggle with.
Logistics. Tracking, warehouse and transport management systems joined for visibility from order to delivery.
Each build gets shaped around the operational and regulatory realities of your industry, rather than the other way round.
Common Questions About Custom API Integration Services
When is a tool like Zapier or Make good enough, and when do we need a custom build?
For a handful of simple connections between mainstream SaaS tools, with straightforward field mapping and no complex rules, a low-code platform is usually the right call and we'll tell you so. Custom work earns its keep when you have five or more systems with overlapping logic, a legacy or in-house system with no decent API, conditional workflows and approval chains, real-time sync that the business depends on, or per-transaction pricing that has started to hurt at volume.
How does a custom build compare on cost to an iPaaS subscription?
A custom build is a larger upfront cost, then a predictable annual figure for maintenance. Subscription platforms look cheaper at first but scale with users, tasks, transactions or connected accounts, and the headline price rarely includes migration, custom connectors, premium support or audit features. For a business running many integrations at volume, owning the integration layer tends to win over a two-to-three year horizon, with no contract renegotiation and no surprise bills. We give you a straight comparison for your situation rather than a generic figure.
What's the typical timeline?
We usually start with a 2 to 3 system MVP covering the highest-impact connections, which runs roughly 6 to 12 weeks for a custom build. A fuller platform with conditional workflows, real-time sync and full audit logging is typically a 4 to 6 month effort. Discovery sets the firm timeline; messy source data and legacy systems are the things that most often extend it.
Can you connect our legacy or in-house systems?
Yes, and that is often the reason a custom build is needed. Older ERP, manufacturing equipment, EDI supplier links and custom-built in-house tools rarely have a modern REST API. We write the adapters and transformation layers to bridge SOAP, XML, flat-file exports and bespoke endpoints, so the awkward systems join in cleanly rather than being left out.
How do you stop integrations breaking when a vendor changes their API?
Third-party APIs change, deprecate endpoints and rate-limit without much warning, so we build for it. That means retry and back-off logic, idempotency handling for duplicate webhooks, monitoring that alerts a human when a sync fails rather than failing silently, and a transformation layer that isolates vendor quirks so a change in one API doesn't ripple through everything else.
What about data security and UK GDPR?
Integrations move personal data between systems, so we build with UK GDPR and ICO guidance in mind from the start: encryption in transit and at rest, role-based access on the principle of least privilege, and immutable audit logs of every data movement. We can host in UK data centres for data residency, and where you process card payments or operate in a regulated sector we build to the relevant standard, such as PCI-DSS or FCA record-keeping requirements.
Do you provide training and ongoing support?
Yes. Every project includes documentation and hands-on sessions pitched at the right level for each role, from business users monitoring dashboards through to your IT staff handling exceptions. After go-live we offer flexible support for maintenance and for adding new systems as your stack changes.