GPT inventory and migration map
Every GPT, file, action, and owner listed, with the right replacement chosen for each one.
The Problem
Your Custom GPT for Business Has a Retirement Date
As of October 2026, OpenAI's Help Center lists December 11, 2026 as the standard retirement date for GPTs. ChatGPT plugins replace them, and GPTs your team uses daily need a tested move, not a rushed copy.
Lost actions
Custom actions don't transfer to the new plugin.
Lost actions
Each action is rebuilt as an MCP server tool and tested against the original.
Login wall
Customers must sign in to ChatGPT to use your GPT.
Login wall
An API assistant runs on your own site with no ChatGPT login.
Test prompts
Nobody saved the prompts that prove the GPT works.
Test prompts
We collect real prompts and compare old and new answers side by side.
Orphaned GPTs
The builder left, and edit access left with them.
Orphaned GPTs
Each replacement's owner, files, and settings are documented at handover.
Your team runs on a few GPTs: one drafts proposals from your price sheet, one answers HR policy questions, and one checks order status through a custom action. Then the notice arrives. New GPTs can't be created on personal plans, a migrated GPT turns read-only, and custom actions don't carry over to plugins. The person who built the customized GPT has left, the action's API key sits in their old notes, and nobody saved the prompts that prove it worked.
We start with an inventory: every GPT your team uses, with its instructions, files, actions, and the prompts people rely on. Then we move each one to the right home: a ChatGPT plugin for internal work, an MCP server for actions that call your systems, or an API assistant for your website. Every replacement is tested against saved prompts before anyone switches, so your workflows keep running instead of breaking on retirement day.
Inventory before migration
Every GPT, file, action, and saved prompt listed, with an owner named for each replacement.
Actions rebuilt properly
Custom actions become MCP server tools with OAuth sign-in instead of one shared API key.
Tested against old answers
Saved prompts run on the old GPT and its replacement, so differences surface before switching.
Our Custom GPT Development Process
From GPT Inventory to Tested Replacement in Five Clear Steps
You approve the migration map before we move anything, then compare old and new answers on your own prompts before anyone on your team is asked to switch.
We look at the GPTs your team uses, what each one does, and which ones call outside systems. You get a migration map, a fixed price, and a plan built around the date in your workspace notice.
What's Included
What You Get With Custom GPT Development for Business
Everything needed to move off the GPT feature without losing what works: an inventory, the right replacement for each GPT, rebuilt actions, and a clean handover.
Compare Options
DeveloperLook vs DIY Migration vs Freelancer
OpenAI's built-in migration suits simple GPTs, and a freelancer suits one small rebuild. Here is how custom GPT AI chatbot solutions compare once actions, websites, and testing enter the picture.
| Feature | DeveloperLookBest fit | DIY Migration | Freelancer |
|---|---|---|---|
| Instructions and files | Rewritten as skills and retested | Built-in migration copies them | Copied over as they are |
| Custom actions | Rebuilt as MCP tools with OAuth | Not moved by the built-in tool | Depends on API experience |
| Testing | Saved prompts compared side by side | Your own spot checks | Varies by person |
| Website use | API assistant on your own site | Not possible inside ChatGPT | Possible with a custom build |
| Team access | Workspace sharing set up | Share Plugin can prefill users | Often left to you |
| Speed | 1 to 2 weeks per batch | Same day for simple GPTs | Depends on availability |
| Ownership | Code and MCP server are yours | Plugin stays in your account | Yours if handed over |
| Cost | Fixed price per batch | Your time within plan limits | Hourly, cheaper for one GPT |
DeveloperLook
DIY Migration
- Instructions and files
- DeveloperLook: Rewritten as skills and retestedDIY Migration: Built-in migration copies them
- Custom actions
- DeveloperLook: Rebuilt as MCP tools with OAuthDIY Migration: Not moved by the built-in tool
- Testing
- DeveloperLook: Saved prompts compared side by sideDIY Migration: Your own spot checks
- Website use
- DeveloperLook: API assistant on your own siteDIY Migration: Not possible inside ChatGPT
- Team access
- DeveloperLook: Workspace sharing set upDIY Migration: Share Plugin can prefill users
- Speed
- DeveloperLook: 1 to 2 weeks per batchDIY Migration: Same day for simple GPTs
- Ownership
- DeveloperLook: Code and MCP server are yoursDIY Migration: Plugin stays in your account
- Cost
- DeveloperLook: Fixed price per batchDIY Migration: Your time within plan limits
Projects We've Built
HR, Learning, and Startup Projects We Have Built
HR, learning, and startup products we built where policies, courses, and help content need clear answers. They show our product work, not GPT migrations.
Herile HR and Project Management Platform Website
- Business
- Dashboard
- SaaS Platform
Gradely E-Learning Website Design & Development
- Education
- Dashboard
- Membership Platform
Edutech E-Learning Web Design & Development
- Education
- Dashboard
- E-commerce
NextEdge Startup Web Design & Development
- Startups
- Technology
- Business
What Our Clients Say
What Clients Say After Launch
Feedback from teams we have built apps, platforms, and websites for.
We had a pretty specific idea of what we wanted our website to become, but I wasn’t sure how easily we could explain all of it to a development team. There were quite a few moving parts, and we were working toward a deadline, so I expected a few things to get lost along the way. That never really happened. They understood what we were trying to achieve, kept us updated throughout the process, and got everything ready within the agreed timeline. The final site feels much easier to navigate, works beautifully on mobile, and is noticeably smoother for our customers. It was a huge relief seeing the original idea actually turn into the website we had in mind.
The mobile experience is probably my favourite part of the new site. We had spent a lot of time making sure the desktop version looked right, and the team kept pushing us to think about how everything would actually feel on a phone too. They were right. The navigation is clean, the interactions feel natural, and everything we’ve tested so far works exactly as it should. They also went through the links, forms, integrations, and other details more than once before launch, which I really appreciated. And even after going live, we could still reach out when something came up. The whole process felt friendly, organised, and surprisingly straightforward.
What I appreciate most is that the website is actually easy for us to manage now. We can update content ourselves instead of sending a developer a message every time we need to change something small. They also paid attention to the technical SEO side, which mattered to us because we didn’t want a new website to create problems for the traffic we already had. I’ve probably asked more questions than I should have since launch, but every question has been handled patiently and without any fuss. The team is easy to work with, they explain things clearly, and when we need something changed, they focus on getting it done rather than making the process complicated.
1,250+
Projects shipped
10+
Years of experience
Top 3%
Upwork Top Rated Plus
5 stars
Average review score
1,250+
Projects shipped
10+
Years of experience
Top 3%
Upwork Top Rated Plus
5 stars
Average review score
Want results like these?
Tell us what you are building. You get a reply within 24 hours on business days, then a written estimate.
Work Culture
Why Teams Trust Us With Their GPT Migration
Teams compare custom GPT development services on speed. The better test is whether every workflow still works after the switch, and these six habits shape every migration.
Dates from OpenAI's notices
We plan around the retirement date in your workspace notice, not a guess. FedRAMP and deferred workspaces have later dates, so we check yours first.
Honest about DIY
If OpenAI's built-in migration moves your GPT cleanly, we tell you to use it. You pay us only for actions, websites, and GPTs it can't handle.
No shared admin keys
Rebuilt actions sign each user in through OAuth instead of reusing one stored key. Your security team can see who called what.
Same answers, proven
We compare old and new answers on real prompts before anyone switches. Your team trusts the replacement because they saw the results.
The right home per GPT
Some GPTs belong in a plugin, some in an MCP server, and some on your website. We choose per GPT instead of forcing one pattern.
You own the rebuild
Plugin files, MCP server code, and test prompts stay in your accounts. Moving to Claude or another model later doesn't mean starting over.
Overview
How does a custom GPT work inside ChatGPT?
DeveloperLook moves each custom GPT your team relies on to a supported home: a ChatGPT plugin, an MCP server for its actions, or an API assistant on your website. Each project includes an inventory, rebuilt actions with OAuth, and side-by-side tests on saved prompts. Projects start at $650 and take 1 to 6 weeks.
DEVELOPERLOOK
Project facts · Custom GPT Development
- Service
- Custom GPT Development (migration to plugins, MCP action rebuilds, website assistants)
- Typical timeline
- 1 to 2 weeks per plugin migration, 3 to 6 weeks with actions or websites
- Platforms
- ChatGPT plugins, OpenAI API, Claude, and your own website
- Built with
- Model Context Protocol, OpenAI API, TypeScript, Python, OAuth
- Experience
- 10+ years of development experience and 1,250+ shipped projects
- Post-launch support
- 30 days of fixes after launch
- Communication
- Calls in US, UK, and AU business hours
- Starting price
- From $650 USD, fixed scope after a GPT review
Reviewed 28 Oct 2026 by Saimul Islam
Good fit
Teams running internal GPTs daily
Your staff use GPTs for proposals, policies, or onboarding every day, and each one needs moving and retesting before the date in your workspace notice.
GPTs with custom actions
Your GPT checks orders or creates tickets through a custom action, and you just learned that actions don't carry over to plugins.
Businesses with a public GPT
You shared a custom ChatGPT with customers through a link, and now you want it on your own website without a ChatGPT login.
Enterprise workspace admins
You manage dozens of GPTs across departments and need an inventory, named owners, and a bulk migration plan with testing.
Agencies that built client GPTs
You built GPTs for clients and need them moved to plugins, MCP servers, or websites under your brand, with tests your clients can review.
Not a fit
Brand-new GPT builds
You want a brand-new GPT built from scratch. OpenAI has closed new GPT creation on personal plans, so we build plugins or API assistants instead.
A full support chatbot
You need a customer support chatbot tied to your help desk and order data. Our AI Chatbot Development page covers that larger build.
AI access to many systems
You need AI tools connected to several company systems at once, well beyond one GPT's actions. Our MCP Server Development page covers that scope.
Budget under $650
Your budget is under $650 and your GPT has no custom actions. OpenAI's built-in migration to a plugin may be all you need.
Not sure we're the right fit?
Book a free call or message us. We'll tell you honestly whether we're the right team.
Pricing
Transparent Starting Prices for Custom GPT Development
These are starting points in USD. Your final price depends on how many GPTs move, their custom actions, and any website use, and you get a fixed proposal after a free GPT review.
For Agencies
White-Label GPT Migration for Agencies and Studios
You own the client relationship. We supply the engineering that moves your clients' GPTs: inventories, plugin rebuilds, MCP servers for their actions, and website assistants. Test reports carry your brand, so the switch looks like your work to every client.
How the partnership works
White label: your client only ever sees your brand
Your clientSees only your brand
You, the agencyOwn the relationship
DeveloperLookBehind your brand
Share the GPT list
Send each client's GPTs, their actions, and who uses them day to day.
- Client needs
- You share the details
- Details received
We map and price
You get a migration map, a fixed price, and a date for each client.
- Scope and plan
- Proposal to resell
- Your quoteYOUR LOGO
Migrate and hand off
We move, test, and document each GPT under your brand for client handover.
- Done by our team
- Your brand on it
- Handed to your clientDone
- Your client
- You, the agency
- DeveloperLook
Share the GPT list
Send each client's GPTs, their actions, and who uses them day to day.
- Client needs
- You share the details
- Details received
We map and price
You get a migration map, a fixed price, and a date for each client.
- Scope and plan
- Proposal to resell
- Your quoteYOUR LOGO
Migrate and hand off
We move, test, and document each GPT under your brand for client handover.
- Done by our team
- Your brand on it
- Handed to your clientDone
Partner with DeveloperLookDelivered under your brand
The Right Technology for Your Project
Technology Stack
We rebuild GPT workflows on the supported paths OpenAI and Anthropic document, using open standards like MCP so your team isn't tied to one model.
ChatGPT- OpenAI API
Anthropic Claude- Model Context Protocol
TypeScript
Python
Node.js
Docker
Cloudflare
Next.js
React
Vercel
PostgreSQL- pgvector
- OAuth sign-in
- Auth0
- Microsoft Entra ID
- Google Workspace
01 / 04
Related Services
Pair a GPT migration with the MCP layer for your systems, retrieval over your documents, a full support chatbot, and agents that run multi-step work.
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DeveloperLook provides RAG development services for teams whose AI must answer from their own documents. We build retrieval augmented generation pipelines with source syncing, permission-aware search, cited answers, and a scored test set, then hand over the code.
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DeveloperLook provides AI chatbot development services for support, sales, and internal teams. As a US-based chatbot development company, we build chatbots that answer from your own content, connect to your helpdesk, CRM, or store, and hand off to a person when unsure.This page
Custom GPT Development
Pairs with the 6 services around it
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DeveloperLook provides AI agent development services for business workflows: agents that qualify leads, read documents, and update your systems, with guardrails, human approval, and tests on your real cases. Custom AI agent development on a fixed scope.
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Frequently Asked Questions
Straight answers on cost, website embeds, actions, and file limits for custom GPTs and what replaces them.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
A custom GPT is a ChatGPT setup built for one job, with its own instructions, knowledge files, and optional actions that reach outside APIs. Teams use them for proposals, policy questions, and onboarding help. OpenAI's Help Center (October 2026) lists December 11, 2026 as the standard retirement date and plugins as the replacement, so new work targets plugins.
No. A GPT answers inside ChatGPT when a person prompts it, while an AI agent works toward a goal across several steps and tools. Actions gave GPTs some reach into other systems, but each step still waited for a user. If you need software that runs multi-step work on its own, our AI Agent Development Services page covers that.
GPT migration starts at $650 to move up to 2 GPTs to ChatGPT plugins with before-and-after testing. Rebuilding up to 4 custom actions as MCP server tools is $1,700, and a Website Assistant Rebuild on the OpenAI API starts at $3,900. API, hosting, and ChatGPT plan costs are billed to your own accounts.
Using a GPT is free on any ChatGPT plan once you sign in, but creating new ones is closed on personal accounts. As of October 2026, OpenAI says Free, Go, Plus, and Pro accounts can't create or publish new GPTs, and editing an existing one still needs an eligible plan. Plugins and API usage follow their own plan rules and prices.
No. OpenAI's Help Center says GPTs are designed to work inside ChatGPT and are not a way to embed ChatGPT in an external website. To put an assistant on your site, you build it with the API. We rebuild the GPT's instructions and files as an API assistant with your branding, which is how you host custom GPT externally without a ChatGPT login.
You integrate it by rebuilding it on the API, not by linking to it. The GPT's instructions become a system prompt, its knowledge files go into a retrieval index, and each action becomes a tool call your backend controls. A chat widget on your site talks to that backend, so you keep the logs, the usage limits, and the branding.
Actions let a GPT call an external API described in an OpenAPI schema, with no authentication, an API key, or OAuth. Teams used them to look up orders, create tickets, or read CRM records. OpenAI's migration FAQ says actions don't transfer to plugins automatically, so we rebuild each one as an MCP server tool and test it against the old behavior.
No. OpenAI's Help Center says GPTs don't use saved memory, custom instructions, or previous conversations, so each conversation starts fresh. Anything a GPT must know has to live in its instructions or knowledge files. When we rebuild a GPT as an API assistant, we can add memory you control, such as saved customer preferences, stored in your own database.
You can attach up to 20 knowledge files to a GPT, each up to 512 MB, according to OpenAI's Help Center in October 2026. Text and document files are also capped at 2 million tokens each. During migration those files move into the plugin's reference files, and larger document libraries go into a retrieval index instead.
Claude Projects are the closest equivalent: shared workspaces with their own knowledge base, uploaded documents, and context, available even on free Claude accounts. Claude also supports skills and connects to tools through MCP, the same protocol ChatGPT plugins use for custom apps. If your team is leaving GPTs anyway, we can rebuild a workflow as a Claude Project plus an MCP server.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
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