ChatGPT Application Development Services

ChatGPT is a model, not a product. What you need is a product built on top of it, with your data, your use cases, your safeguards, and your user experience. Generic ChatGPT integrations fail because they bolt the model onto an existing workflow without redesigning the workflow around what AI can actually do.
We build custom ChatGPT applications that are designed around your specific use case, from the prompt architecture to the data layer to the interface your users actually interact with.

See our work
  • GPT-4o, GPT-4 Turbo, and OpenAI API integration with your proprietary data

  • Custom prompt engineering and fine-tuning for your domain

  • RAG (retrieval-augmented generation) for accurate, source-backed responses

  • 20+ AI products shipped using OpenAI models

Recent outcomes

Conversational AI · B2B SaaS startup

Built a domain-trained AI assistant that handled 70% of routine support queries without human intervention. Shipped in 12 weeks.

70% queries automated

AI Document Processing · Financial services

Built a GPT-4o extraction pipeline processing contracts and invoices. 20,000+ daily transactions, manual review eliminated.

20,000+ daily transactions

Internal Knowledge Assistant · Professional services

Deployed a RAG-powered knowledge assistant on proprietary SOPs and policy documents. Staff find answers in seconds instead of searching SharePoint.

12 weeks to production
4.9 / 5 on ClutchSee all work

Recognition

Sound familiar?

  • Your team is using ChatGPT manually when it should be automated into your workflow?

  • Generic AI chatbots giving wrong answers because they don't know your business?

In short

RaftLabs builds custom ChatGPT applications using GPT-4o and the OpenAI API for clients in the US, UK, and Australia. We integrate proprietary data via RAG, engineer prompts for your use case, and ship the full product. 20+ AI products delivered. A focused application costs $20,000 to $50,000.

Trusted by

Vodafone
Nike
Microsoft
Cisco
T-Mobile
Aldi
Heineken
GE

AI development, by the numbers

AI products shipped in 24 months
20+
from kick-off to production-ready AI product
12 weeks
rated by clients on Clutch
4.9/5
years shipping software and AI products
9+

Building with ChatGPT vs. using ChatGPT

Most businesses start with ChatGPT.com. Teams use it manually, someone copies a document into the chat, asks a question, and pastes the answer somewhere else. That works until you want consistency, scale, or the AI to act on your data rather than public training data.

A custom ChatGPT application replaces the manual step with a product. The model receives your documents automatically, your data is indexed and searchable, the prompts are engineered for your use case, and the output flows into your workflow without anyone copying and pasting.

The difference between "using ChatGPT" and "building with ChatGPT" is the gap between a tool and a product.

If your use case requires retrieving accurate answers from a large document library, we build the RAG pipeline that connects GPT to your data. For integrations using Claude, Gemini, or open-source models, see our generative AI integration service.

Capabilities

What we build with ChatGPT and OpenAI

Internal knowledge assistants

An AI assistant that answers questions using your internal documents, policies, product knowledge, and SOPs. Staff get instant, accurate answers without searching through SharePoint or asking a colleague. Sources are cited. Wrong answers are visible because they're grounded in documents you control.

Customer support AI

An AI layer that handles the first line of customer queries using your product documentation, FAQs, and support history. Complex queries are escalated to human agents with context. Support volume drops. Response time drops. CSAT goes up.

Document processing and extraction

AI that reads your documents, contracts, invoices, reports, forms, and extracts structured data from them. Review contracts for specific clauses. Classify support emails by topic. Extract line items from purchase orders. What took hours takes seconds.

AI copilots for existing software

An AI assistant embedded in your existing application, a CRM, an ERP, a project management tool, that helps users draft communications, generate reports, answer questions, or suggest next actions. The AI knows the context of what the user is doing because it can see the application data.

Content generation with approval workflows

AI-generated content, product descriptions, email campaigns, social posts, reports, with human review and approval before publishing. The AI does the first draft. Humans edit and approve. You get the volume without losing quality control.

Conversational data interfaces

Query your database in plain English. Instead of writing SQL or waiting for a report from the BI team, business users ask questions in natural language and get answers from your data. We build the query translation layer, the data access controls, and the result presentation.

Why us

Why teams choose RaftLabs

  1. Senior engineers build what they scope

    The engineers who assess your problem also build the solution. No bait-and-switch, no offshore handoff after the contract is signed. The team you meet in week 1 ships in week 12.

  2. Fixed price before development starts

    We scope the work, calculate the cost, and lock it in writing before any development starts. A scope change is a change request: priced, agreed, or dropped. It never absorbs into the project and appears on the final invoice.

  3. 9 years and 100+ products shipped

    Clients include Vodafone, T-Mobile, Aldi, Nike, Cisco, and Lockheed Martin. Track record across AI, SaaS, mobile, automation, and enterprise platforms across healthcare, fintech, logistics, and hospitality.

  4. Compliance built in from the start

    GDPR, HIPAA, SOC 2 — compliance requirements are scoped in week 1, not retrofitted before launch. We have shipped HIPAA-compliant systems for US healthcare clients and GDPR-compliant products for European markets.

Have a ChatGPT use case? Let's scope the application.

Tell us what you want to automate or improve with AI. We'll design the architecture and give you a fixed cost to build it.

Process

How we work

01

Use case scoping

We define exactly what the ChatGPT application needs to do, inputs, outputs, accuracy requirements, and what happens when the AI gets it wrong. Most projects fail because the use case is too vague. We get specific before we design anything.

  • Use case definition with input/output specification

  • Accuracy requirements and acceptable failure modes

  • User workflow mapping (who uses this, when, and why)

  • Fixed-cost scope agreed before any development begins

02

Data architecture & RAG

If your application needs to answer questions from your proprietary data, we design the RAG pipeline, indexing your documents, database records, or knowledge base into a vector store that the model can search before generating a response. Your data, not public training data, drives the answers.

  • Knowledge base audit and ingestion pipeline design

  • Chunking strategy and embedding model selection

  • Vector store setup and indexing

  • Hybrid retrieval for maximum accuracy

03

Prompt engineering

We build and test the system prompts that define how the model behaves for your use case, what it answers, how it answers, when it declines, and how it cites sources. Good prompt engineering is the difference between a useful product and an inconsistent demo.

  • System prompt design and constraint definition

  • Few-shot examples for domain-specific behaviour

  • Guardrail design for out-of-scope inputs

  • Output format specification for downstream use

04

Application build

We build the application interface and backend, the UI your users interact with, the API layer that handles model calls, the approval workflows for human review, and the logging infrastructure for monitoring. The ChatGPT capability is embedded in a product, not a raw chat window.

  • Frontend interface design and development

  • API layer and request handling

  • Human review and approval workflows where needed

  • Usage logging and audit trail

05

Testing & monitoring

We test the application against real inputs, including the edge cases that break most AI products. Hallucination patterns, out-of-scope queries, and high-stakes decisions are all tested before launch. Post-launch monitoring tracks response quality, latency, cost, and user adoption.

  • Systematic hallucination testing

  • Edge case and adversarial input testing

  • User acceptance testing

  • Production monitoring for quality, cost, and latency

Ready to build a ChatGPT application that actually works?

Tell us your use case and we'll design the prompt architecture, data pipeline, and application interface. Fixed cost.

What clients say

What our clients say

Three-year average engagement. Founders and operators describing the work in their own words. No marketing varnish.

Amer Abu Khajil
Amer Abu Khajil
Canada flagCanada
Founder, Peak Studios & Perceptional

I found RaftLabs to be the perfect partner for Perceptional, with their expertise in helping startup founders build MVPs, a free consultation, a prototype that matched my vision, and their unwavering support.

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Frequently asked questions

We build custom applications that use OpenAI's GPT models for specific business use cases: AI assistants for customer support or internal knowledge search, document processing tools that summarise, extract, or classify content, AI copilots embedded in existing software, automated content generation tools with approval workflows, and conversational interfaces for complex data queries. The use case determines the architecture, not all ChatGPT applications are chatbots.

Out-of-the-box ChatGPT doesn't know your business. We make it accurate through three approaches: (1) RAG (retrieval-augmented generation), the model retrieves relevant documents from your knowledge base before generating a response, so answers are grounded in your actual data. (2) System prompts and fine-tuning, we engineer prompts that constrain the model's behaviour and, where appropriate, fine-tune a model on your domain-specific examples. (3) Guardrails, we build validation layers that catch and handle responses that fall outside expected parameters.

Yes. We build RAG pipelines that index your internal documents, PDFs, Word files, SharePoint content, database records, website content, into a vector store that the model can search before generating responses. The model doesn't guess based on its training data, it retrieves the right information from your sources and uses that to generate the response. Answers include source citations so users can verify them.

Hallucination is a real risk with any language model. We reduce it through RAG (answers are grounded in your actual documents, not model memory), confidence scoring (responses that don't find relevant sources are flagged or escalated), human review workflows for high-stakes decisions, and response logging so you can identify and fix systematic errors. We don't promise zero errors, but we design systems with the failure modes in mind.

A focused first application, for example, an internal knowledge search assistant or a document summarisation tool, typically runs $20,000--$50,000. A full AI platform with multiple use cases, custom integrations, and a user interface typically runs $60,000--$150,000. The cost depends on the number of use cases, the complexity of the data pipeline, and the user interface requirements. We scope every project before pricing it.

Yes, you can. The API is well documented and the basic integration is straightforward. The hard part is: designing prompts that produce consistent, accurate results for your use case; building the RAG pipeline that connects the model to your data; handling failure modes (timeouts, rate limits, wrong answers); building the user interface and approval workflows around the AI capability; and testing and monitoring the system in production. These are engineering and product problems, not just API calls. We've solved them 20+ times.

Work with us

Tell us what you need. We'll tell you what it would take.

We scope ChatGPT Application Development Services in 30 minutes. You walk away with a clear cost, timeline, and approach. No commitment required.

  • Scope and cost agreed before work starts. No surprises. No obligation.
  • Working prototype within 3 weeks of kickoff.
  • Pay by milestone. You see progress before each invoice.
  • 60-day post-launch warranty. Bug fixes, UI tweaks, and deployment support. No retainer.
  • All conversations are NDA-protected.