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Custom GPT Development · Reading

Custom GPT Development in Reading

Building custom GPTs for Reading teams — a configured assistant with your instructions, your reference documents and, where useful, actions that call your own systems. The honest framing is that a custom GPT is a fast way to get something useful in front of people, and a poor place to put anything you would not email to a colleague.

Why this comes up

The problem

Everyone is prompting from scratch, badly and differently. The same task produces different quality depending on who asked, and the good prompt someone worked out lives in their notes.

What you get

What we deliver

  • Instructions written and tested against the task rather than guessed at once
  • Reference documents attached, so answers draw on your material
  • Actions calling your own APIs where the assistant needs live data
  • Sharing scoped to your workspace, not published where it need not be
  • A tested set of example inputs, so quality is checked rather than assumed
  • An honest assessment of whether this should be a custom GPT at all

Want this scoped for your business in Reading?

Thirty minutes, no charge, no sales script. You leave with a written summary of what custom gpt development would actually involve — whether or not you use us.

Book a 30-minute call

Working in Reading

South East

Reading anchors the Thames Valley technology corridor, and local firms are often part of large enterprise supply chains where security review and integration standards are set by someone else.

Work here usually has to satisfy someone else's security and integration standards, because clients sit inside larger enterprise supply chains.

Sectors we work with in Reading

  • Technology
  • Telecommunications
  • Financial Services
  • Professional Services

What we work with

Technologies and platforms

  • OpenAI
  • ChatGPT
  • REST APIs
  • OpenAPI

Who we work with

Industries we serve

  • Professional services
  • Marketing agencies
  • Education
  • Recruitment
  • Property

Why us

Why Reading 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

  1. Step 1

    Free consultation

    A 30-minute call to understand the problem. You keep the written summary either way.

  2. Step 2

    Proposal

    Scope, timeline and a fixed price, in writing, before anything starts.

  3. Step 3

    Build

    Short cycles with regular check-ins, so you see progress rather than hear about it.

  4. Step 4

    Launch and support

    We handle the go-live and stay available afterwards.

Custom GPT Development in Reading — common questions

When is a custom GPT the wrong choice?
When it needs to handle personal or confidential data, integrate deeply with internal systems, or be embedded in your own product. A custom GPT is convenient precisely because it is lightweight, and those requirements point at a proper API integration instead.
Who can see the documents we attach?
Anyone who can use the GPT can generally get at the reference material through it, whatever the instructions say. Treat attached documents as visible to every user of that GPT, and scope sharing accordingly.
Can it access our systems?
Yes, through actions that call your APIs, with authentication. It works well for reads — looking up a record, checking a status. For anything that changes data, the same caution applies as to any automated caller of your API.
Why does the same task give different results?
Usually because the instruction is ambiguous rather than because the model is unreliable. Most of the improvement in a custom GPT comes from specifying the output format and the edge cases precisely, which is unglamorous and effective.
Do you work with businesses across Berkshire?
Yes. We are based in Leicester, United Kingdom and work with clients throughout South East, including Reading and the surrounding Berkshire area. Most collaboration happens remotely, and we travel for kick-offs and key milestones.
What kind of Reading businesses do you usually work with?
Work here usually has to satisfy someone else's security and integration standards, because clients sit inside larger enterprise supply chains. Beyond that we work across Technology, Telecommunications, Financial Services and Professional Services.
Do you cover the areas around Reading?
Yes — we work throughout South East, including Oxford, London, Milton Keynes, Southampton. Reading is an urban area of roughly 340,000+, and we take on work across the wider Berkshire region rather than the city boundary alone.

Talk to us about Custom GPT Development in Reading

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

Or reach us directly

07707 771599admin@asionis.com

Leicester, United Kingdom