Custom GPT Development

Build a specialized AI assistant for your team or customers using OpenAI’s Custom GPT platform. We handle the knowledge engineering, action configuration, prompt design, and testing — delivering a polished GPT that your people actually want to use, deployed in days not months.

$3,000 – $10,000

Build Your Custom GPT View All Services

What’s Included

Everything from concept to deployed GPT — built by engineers who understand both the platform’s capabilities and its limitations.

🏗

Custom GPT Builder Configuration

We configure your GPT from the ground up: name, description, conversation starters, system instructions, and personality. The system prompt is carefully engineered — not a paragraph of vague instructions, but a structured document that consistently produces the behavior you want across thousands of conversations.

📚

Knowledge Base Upload & Optimization

We curate, format, and upload your knowledge files for maximum retrieval quality. This means cleaning documents, structuring content with clear headers, removing noise, splitting large files strategically, and adding metadata. The difference between “upload your PDFs” and professional knowledge engineering is dramatic — our GPTs give accurate, specific answers instead of vague summaries.

⚙

Action Configuration

Custom Actions let your GPT call external APIs — checking order status, querying your database, creating tickets, sending notifications. We design the OpenAPI schemas, handle authentication (OAuth, API keys), build the error handling, and test every action thoroughly. Your GPT becomes a functional tool, not just a chat interface.

🧪

Comprehensive Testing

We test your GPT against 50-100 real-world queries covering: happy paths, edge cases, out-of-scope questions, adversarial prompts, and multi-turn conversations. Every failure mode is addressed in the system prompt or knowledge base. You get a test report showing exactly how the GPT performs across your use cases.

🚀

Deployment & Distribution

We deploy your GPT to the right audience: private to your ChatGPT Team workspace, shared via link with specific users, or published to the GPT Store for public discovery. Includes branding (profile image, description), category selection, and promotion strategy for public GPTs.

How It Works

Fast, focused development. Most Custom GPTs are designed, built, tested, and deployed within 1-2 weeks.

Use Case Workshop

A 60-minute session to define exactly what your GPT should do, who will use it, what knowledge it needs, and what actions it should take. We document the specification and identify knowledge gaps that need filling before development starts.

Knowledge Engineering

We collect, clean, structure, and optimize your knowledge files. This is where most DIY GPTs fail — raw document uploads produce mediocre results. Our knowledge engineering process ensures the GPT retrieves the right information for the right questions consistently.

Build, Test & Refine

We build the GPT, configure actions, write the system prompt, and run it through our test suite. You review the results and request adjustments. We iterate until the GPT consistently meets your quality bar across all test scenarios.

Deploy & Train

We deploy the GPT, share access with your team, and provide a user guide covering best practices for getting the most out of it. Includes a 30-minute training session and 2 weeks of post-launch refinement as your team discovers new use cases and edge cases.

Who This Is For

Teams that want a specialized AI assistant without the cost and complexity of a custom API integration.

Sales & Customer Success Teams

A GPT trained on your product documentation, pricing, competitive intelligence, and objection handling. Your sales reps get instant, accurate answers to prospect questions instead of searching through Confluence. Customer success managers get a co-pilot that knows every feature, limitation, and workaround in your product.

Professional Services Firms

Lawyers, accountants, consultants — anyone whose value comes from specialized knowledge. A Custom GPT trained on your firm’s precedents, methodologies, templates, and domain expertise becomes a junior associate that never sleeps. It drafts, researches, and summarizes so your senior professionals focus on judgment and client relationships.

Companies with Complex Products

If your product has hundreds of configuration options, integration patterns, or use cases, a Custom GPT becomes the best support tool you have ever deployed. It handles the long tail of specific technical questions that are too niche for your help center but too frequent to ignore.

Frequently Asked Questions

Do we need ChatGPT Plus or Team to use Custom GPTs?

For internal team GPTs, yes — each user needs a ChatGPT Plus ($20/month) or Team ($25/month per user) subscription. Team plans are recommended for businesses because they include admin controls, shared GPT management, and data privacy guarantees (OpenAI does not train on Team plan data). For public GPTs published to the GPT Store, anyone with a free ChatGPT account can use them.

How much data can we upload to the knowledge base?

Each Custom GPT supports up to 20 files, with each file up to 512 MB and a total of about 2 million tokens of searchable content. That is roughly equivalent to 10,000 pages of text. For most businesses, this is more than enough. If you have more data, we use strategic curation — identifying the most valuable 20% of content that answers 80% of questions, and structuring it for maximum retrieval quality.

Can a Custom GPT replace our help center?

Not replace, but dramatically enhance. A Custom GPT is best as a complement to your existing help center — it provides conversational, context-aware answers that help centers cannot. Customers who would have submitted a support ticket can often get their answer from the GPT instead. We recommend embedding a link to the GPT from your help center and tracking deflection rates.

What is the difference between a Custom GPT and an API integration?

Custom GPTs are faster and cheaper to build — days instead of weeks, thousands instead of tens of thousands. They live inside the ChatGPT interface, so there is no frontend to build. The tradeoff: less control over the user experience, dependency on OpenAI’s platform, and ChatGPT subscription requirements. If you need AI embedded in your own product with full control, go with API integration. If you need an internal tool fast, Custom GPTs are the right choice.

Get a Specialized AI Assistant in Days

Book a free GPT scoping session. We will identify the best use case for your organization and outline what a Custom GPT would look like — with honest guidance on whether a GPT or API integration is the better fit.

Book Free GPT Scoping Session

Custom GPT Development — Available Worldwide

We deliver custom gpt development services globally. Select your country:

United States United Kingdom Canada Australia Germany Netherlands Ireland France Israel Italy Spain Sweden Switzerland Austria Poland