// FOUNDRY5
LLM Integration

CLAUDE, GPTAND MODELSIN PRODUCTION.

LLM integration services UK teams can actually ship: we wire Claude, GPT and open models into your product and operations, with grounding, evals and guardrails, not a thin wrapper around an API key.

LLM Integration visual
2-3 wksFirst feature live
Modelagnostic, no lock-in
30 daysPost-launch support
100%Code ownership
The problem

Most LLM integration services UK companies buy are a thin wrapper around someone else's API.

01

An API key is not an integration.

Piping a prompt to an endpoint and rendering the reply looks like an AI feature for about a week. Then it hallucinates in front of a customer, the bill spikes on a busy day, and nobody can explain why an answer changed. The hard part is everything around the model, and that is exactly what a wrapper skips.

02

The wrong model in the wrong place.

Teams pick a model on hype, then pay premium rates for a task a cheaper one does just as well, or ship a slow one where latency kills the feature. Model choice is an engineering decision about accuracy, cost, latency and privacy, made per task, not a brand loyalty contest.

03

Your data and your costs run unguarded.

Without grounding, the model invents. Without cost controls, usage compounds silently. Without the right data terms, your prompts may be training someone else's model. Each of these is a production incident waiting to happen, and none of them show up in a demo.

We integrate LLMs into real production software, with RAG grounding, evals, guardrails, fallbacks and cost controls built in.

See what you get →
What you get

Not a plugin. An LLM engineered into your product.

Every build ships with the same core package. It is the baseline any LLM integration services UK businesses pay for should meet, whether it powers a product feature or an internal workflow.

Model selection and benchmarking

Claude, GPT, and open-weight models tested against your real task on accuracy, latency, and cost per call, so the choice is evidence, not a guess.

RAG grounding where it is needed

Retrieval over your own data so the model answers from your content and cites it, instead of inventing plausible-sounding fiction.

Evals and regression testing

A test suite for model outputs, so a prompt change or model upgrade cannot quietly break behaviour you rely on.

Guardrails and fallbacks

Input and output validation, refusal behaviour for out-of-scope requests, and graceful fallbacks when a provider is slow or down.

Cost controls and monitoring

Caching, model routing, token budgets, and per-feature cost tracking, so the inference bill stays predictable as usage grows.

30 days post-launch support

Prompt tuning, eval maintenance, and model-drift monitoring after launch, from the team that built it.

How we build

From API key to production feature. Here is exactly how.

#PhaseWhat happensWhen
01Scope and model fitWhat the feature must do, what good looks like, and which models are even in the running. We define the eval set and the accuracy, latency, and cost bar before writing integration code.Week 1
02Prototype and benchmarkA working integration tested against your real inputs across candidate models. We measure accuracy, latency, and cost per call, and pick the model on evidence.Weeks 2-3
03Production buildThe integration built into your app: RAG grounding, tool and function calling, streaming, error handling, and connection to your existing systems.Weeks 3-5
04Evaluation and hardeningAdversarial inputs, prompt injection attempts, and edge cases run against the eval suite. We add guardrails and fallbacks until behaviour holds under pressure.Weeks 5-6
05Deploy and monitorLive deployment with output logging, cost tracking, and drift monitoring, plus an eval suite that catches regressions when you upgrade models later.Ongoing
Our stack

Tools chosen for the job, not the hype.

Models
Anthropic ClaudeOpenAI GPTLlamaMistral
Integration
REST / StreamingFunction CallingLangChainTool Use
Grounding
RAGVector DBspgvectorPinecone
Backend
PythonFastAPIn8nPostgres
Evaluation
Custom EvalsRegression SuitesHuman-in-the-loop
Monitoring
LangSmithCost TrackingDrift Detection
Is this the right fit

We are direct about who we work best with.

This is right for you if

You want LLM integration services UK engineering teams can own and maintain.

  • You have a product or workflow where an LLM would add real value, not just a demo
  • You are worried about hallucination, cost, security, or provider lock-in, and you are right to be
  • You want the model grounded in your own data, with answers you can trace
  • You need evals and guardrails so an upgrade does not silently break the feature
  • You want the integration owned by your team, not rented from a black-box vendor
  • You have wired an API key to a chat box and watched it fall over in production
Probably not the right fit if

You want something we cannot do well.

  • You want a one-off ChatGPT wrapper with no evals, grounding, or plan to maintain it
  • You want to add an LLM because competitors have one, with no real use case
  • You want the cheapest possible integration regardless of accuracy or data safety
  • You need a fixed answer that a simple rule or script would deliver more reliably

If any of these describe you, we will tell you on the first call rather than waste your time or ours.

What founders say

Results over promises.

David

David

Founder at Seconddate

Foundry 5 really impressed me with their work on my AI-powered dating app. They nailed the UI/UX, starting with core app screens and then translating that vision to the web. The React site they built is sleek and polished - exactly what I was hoping for. What I appreciated most was their thoughtful approach and how easy they were to work with. They got the job done without needing me to micromanage.

Phil Blows

Phil Blows

CEO at StreaksAI

Foundry 5 surpassed all expectations in delivering our web development product swiftly and flawlessly. Their speed and eye for detail, especially under tight time constraints, showcase their commitment to excellence.

Liam Farley

Liam Farley

CEO, Xcelsior Capital

Working with Foundry 5 has been a great experience from start to finish. They seamlessly translated our vision into a website that not only showcases our brand and operations but also enhances our online presence as an investor in natural resources. Nothing was too much for them and they always put the client first.

Libby Tanswell

Libby Tanswell

CEO of Ove

Working with Foundry 5 to create the Ove app has been an absolute pleasure. Their professionalism, work ethic, and willingness to always go the extra mile has really impressed me. I would recommend them to anyone.

Daisy Harvey

Daisy Harvey

Loom Founder

Foundry 5 have gone above and beyond to bring my vision of Loom to life. Not only this, but they continue to be an integral part of our team. They are lovely people to work with, and I recommend them to anyone looking for a software partner. Particularly for non-technical tech founders (like me!) who need to ensure that their business is in safe hands.

Chris Jones

Chris Jones

Chief Product Officer Gather

The team has been instrumental in driving both the design and development of Gather, pairing a proactive, highly responsive workflow with the technical depth needed to handle our platform's complexity. Their partnership continues to move the product forward in a reliable and impactful way.

How we compare

Engineered integration vs. a wrapper vs. DIY. An honest comparison.

FeatureFoundry 5Thin wrapperIn-house
Model chosen on benchmarked evidence
RAG grounding on your own data
Evals and regression testing
Guardrails and fallbacks
Cost controls and monitoring
No provider lock-in
You own the code and can extend it
Honest advice on where an LLM fits
Investment

Transparent pricing. No hidden costs.

Fixed scope

Know exactly what you are paying.

Pricing for LLM integration services UK founders can plan around: we scope the work, agree a price, and stick to it. No surprise invoices and no scope creep charges. You get a written scope document before code starts, and you own the integration outright once it is live.

  • Written scope before any code
  • Fixed price for the agreed scope
  • No lock-in to one provider
  • Risk-free pilot on first engagement
Sprint-based

Flexibility when you need it.

For AI features that grow: new models, new use cases, new surfaces in the product. You reprioritise at the start of each sprint as you learn what actually moves the numbers.

  • Reprioritise each sprint
  • Weekly progress updates
  • Scale up or down as needed
  • Same team, continuous context
FAQ

Questions we hear often.

Anything else? Just book a call. We'd rather talk than write another FAQ entry.

Book a 30-minute discovery call →

Risk-free first project · Full refund if you’re not satisfied

Whichever one wins on your task, and often it is more than one. We benchmark the candidates against your real inputs and measure accuracy, latency, and cost per call. Claude and GPT are strong general models with different strengths; open-weight models like Llama and Mistral make sense when cost, data residency, or self-hosting matters. We frequently route between models — a cheap one for easy cases, a stronger one for the hard ones — because that is usually cheaper and better than committing to a single provider.

Hallucination is contained with retrieval-augmented generation, output validation, and confidence checks, so answers come from your content and the system knows when to refuse rather than guess. Data leakage is handled by using providers under agreements that prohibit training on your data, documenting exactly what is sent and retained, and running open models in your own environment when a use case demands it. We also test with adversarial and prompt-injection inputs before launch.

Connecting a model — Claude, GPT, or open-source — into your app, workflow, or data so it does useful work: chat, search, summarisation, drafting, support, or agent-style actions. Doing it properly means grounding the model in your data, adding evals and guardrails, building fallbacks and cost controls, and wiring it into your existing systems through APIs, streaming, and tool calling. The model is the small part; the engineering around it is the integration.

Yes. Most of our LLM work goes into products and internal tools that already exist. We connect to your current APIs, database, and authentication, and expose the AI feature wherever your users already are. It behaves like a native feature of your system — versioned, tested, and owned by you — rather than a separate tool bolted on.

Caching, prompt optimisation, model routing, and token budgets, with per-feature cost tracking from day one. We route easy requests to cheaper models and reserve premium models for the cases that need them, so you can see exactly what each feature costs. Nobody should be surprised by their inference bill at the end of the month.

No, and we design against it. We keep the model behind an abstraction so you can switch providers or add a new one without rewriting your product, and the eval suite lets you compare a new model against the current one safely. Avoiding lock-in is one of the main reasons to have the integration engineered properly rather than hard-wired to a single API.

A focused feature is typically two to three weeks from scope to live. A larger integration with RAG grounding, evals, and multiple surfaces runs four to eight weeks. We agree the timeline in writing before any code, and you see a working prototype benchmarked on your real inputs in week two or three, before you commit to the full build.

Ready to build?

Tell us where an LLM would actually help.

Book a 30-minute LLM scoping call. No pitch. We will tell you whether the LLM integration services UK teams like yours need are worth building here, which model fits, and how to ship it without the hallucination, cost, and lock-in traps.

Risk-free first project · Full refund if you’re not satisfied