LangChain Development · London
LangChain Development in London
Building LLM applications on LangChain for London organisations, with attention to the trade the framework makes. Its abstractions get you to a working prototype quickly and then sit between you and the model — so when output is wrong in production, the first question is what prompt was actually sent, and answering that requires tracing you should build in from the start.
Why this comes up
The problem
The chain produces a poor answer, and nobody can see what was retrieved, what was in the prompt or which call failed.
What you get
What we deliver
- Tracing instrumented from the first version, not added after a problem
- The composed prompt logged, since that is what the model actually received
- Abstractions used where they earn their place and bypassed where they do not
- Token consumption and cost measured per request rather than per month
- Failure handling for the model being slow, rate limited or unavailable
- Evaluation against a fixed set of cases so changes can be judged
Want this scoped for your business in London?
Thirty minutes, no charge, no sales script. You leave with a written summary of what langchain development would actually involve — whether or not you use us.
Working in London
London
London clients usually come to us because they want senior people actually on their project rather than a large agency's B team, and because Midlands rates buy considerably more delivery per pound.
Clients here are usually replacing an agency, and want senior people on the work at rates that are not Central London rates.
Sectors we work with in London
- Financial Services
- Professional Services
- Technology
- Media
- Hospitality
- Retail
What we work with
Technologies and platforms
- LangChain
- Python
- Claude API
- LangSmith
Who we work with
Industries we serve
- SaaS businesses
- Professional services
- Financial services
- Healthcare
- Technology companies
Why us
Why London businesses choose Asionis
- Projects typically launched within 4–8 weeks
- No long-term contracts required
- All team members UK-based
- Dedicated account manager and development team
- Transparent reporting with monthly performance metrics
- Scalable from startup to enterprise
How we work
- Step 1
Free consultation
A 30-minute call to understand the problem. You keep the written summary either way.
- Step 2
Proposal
Scope, timeline and a fixed price, in writing, before anything starts.
- Step 3
Build
Short cycles with regular check-ins, so you see progress rather than hear about it.
- Step 4
Launch and support
We handle the go-live and stay available afterwards.
Other services in London
Looking for the full picture? See our LangChain Development services, everything we do in London or browse everything we do.
LangChain Development in London — common questions
- Why is tracing the first priority?
- Because the framework composes your prompt from several pieces and you never see the result. Debugging a wrong answer means knowing exactly what was sent, what was retrieved and in what order — and reconstructing that from application logs afterwards is close to impossible.
- Should we use every abstraction available?
- No. Some genuinely save work and others add a layer over a single API call, which costs you clarity for no benefit. Using the framework where it helps and calling the model directly elsewhere produces code that is easier to reason about.
- How do we know a change improved anything?
- By running it against a fixed set of cases with known good answers. Without that, changes are judged by trying a few prompts by hand, which reliably rewards changes that improve the examples someone happened to test.
- What breaks in production that did not in development?
- Rate limits, latency and unusual inputs. A chain that works on ten hand-picked examples meets real users with adversarial phrasing, empty inputs and requests that exceed a context window — and each needs a defined behaviour rather than an exception.
- Do you work with businesses across Greater London?
- Yes. We are based in Leicester, United Kingdom and work with clients throughout London, including London and the surrounding Greater London area. Most collaboration happens remotely, and we travel for kick-offs and key milestones.
- What kind of London businesses do you usually work with?
- Clients here are usually replacing an agency, and want senior people on the work at rates that are not Central London rates. Beyond that we work across Financial Services, Professional Services, Technology, Media, Hospitality and Retail.
- Do you cover the areas around London?
- Yes — we work throughout London, including Reading, Milton Keynes, Cambridge, Brighton. London is an urban area of roughly 9,000,000+, and we take on work across the wider Greater London region rather than the city boundary alone.
Talk to us about LangChain Development in London
A 30-minute call with someone who would actually work on it. No sales script, no obligation.
- Projects typically launched within 4–8 weeks
- No long-term contracts required
- All team members UK-based
- Dedicated account manager and development team
- Transparent reporting with monthly performance metrics
- Scalable from startup to enterprise