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Custom GPTs are being deprecated: what should we use ...

ChatGPT & OpenAI

If you've built a fleet of Custom GPTs for your team and just got the deprecation notice, I get it — it stings. But here's the practitioner's take: this isn't the end of AI-powered workflows, it's a forcing function to graduate onto infrastructure that was always more robust anyway. Whether you're running a 200-person business account or a solo marketing shop, your options today are genuinely better than Custom GPTs ever were — you just need to know where to look and what questions to ask before you migrate.

What's Actually Happening with Custom GPTs

First, let's be precise about what's being deprecated and what isn't, because the Reddit thread from r/ChatGPT has surfaced a lot of understandable confusion on this. OpenAI is deprecating the GPT Store / Custom GPTs product as a publicly-shared marketplace feature within the ChatGPT interface. This affects organizations that built Custom GPTs and shared them internally via the GPT Store or direct links.

What this means in practice:

What this does not necessarily mean:

Key Insight: Your Custom GPT's system prompt and knowledge files are the actual IP you built. Every migration path below can absorb that work directly — nothing you wrote is wasted.

The Four Real Alternatives (And Who Each One Is For)

A common question in the r/ChatGPT community right now is simply: "What do I replace this with?" The honest answer is that it depends on your technical lift tolerance, your team size, and how much customization you actually need. Here's the breakdown.

Alternative Technical Lift Best For Cost Range
ChatGPT Projects Very Low Small teams, simple workflows Included in Plus/Team plans
Claude Projects (Anthropic) Very Low Document-heavy workflows, writing tasks $20–$25/month per user
OpenAI Assistants API Medium–High Dev teams, production workflows API token costs, ~$0.002–0.06/1K tokens
Third-party platforms (Botpress, Voiceflow, etc.) Medium Customer-facing bots, structured flows $50–$500+/month

Option 1: ChatGPT Projects

If your Custom GPTs were essentially "persistent conversations with a system prompt and some uploaded files," ChatGPT Projects replicate about 80% of that functionality. You can set custom instructions, upload reference documents, and share projects across a Team account. The UX is familiar for your existing users, which matters a lot when you have 200 people to migrate.

The limitation: Projects don't have the same discoverability or "launch pad" feel that Custom GPTs had. There's no marketplace card your users can click. You'll need to share project links directly or build a simple internal wiki with links to each Project.

Option 2: Claude Projects (Anthropic)

This is the option I'd push hardest for teams that were using Custom GPTs primarily for writing, analysis, or document-heavy tasks. Claude's Projects feature gives you persistent instructions, uploaded knowledge files, and significantly larger context windows — up to 200K tokens on Claude 3.5 and 3.7 models. For workflows where someone needs to reference a 50-page brand guidelines doc or a full campaign brief alongside their prompt, this is a material upgrade.

I use Claude Projects daily for Buddy (the open-source Google Ads agent), specifically because the context window means I can load full account summaries, keyword lists, and ad copy history into a single session without truncation anxiety. That same capability translates directly to marketing, legal, HR, or ops workflows.

Best Practice: When migrating to Claude Projects, paste your Custom GPT's system prompt directly into the Project instructions field first. Then test 10–15 representative user queries to identify gaps before rolling out to your team. Most prompts need only minor tweaking — verb tense adjustments, removing OpenAI-specific formatting references, and re-testing any tool-use instructions.

Option 3: OpenAI Assistants API

If your organization has engineering resources, the Assistants API is where you should have been living all along. Custom GPTs were always a consumer-grade shortcut for what the API can do with more control, better logging, and actual reliability guarantees. The Assistants API gives you:

The catch: this requires a developer to build and maintain the wrapper. If you're a 200-person company and you had an internal dev who set up the Custom GPTs, they can migrate to the Assistants API in a week or two of focused work. If the Custom GPTs were built by a non-technical ops person using the no-code interface, you'll need to bring in help or pick a different path.

Option 4: Third-Party Platforms

Platforms like Botpress, Voiceflow, Stack AI, and Dify sit between "no-code Custom GPTs" and "full API build." They give you visual workflow editors, multi-model support (use GPT-4o, Claude, Gemini in the same bot), and integrations with Slack, Teams, CRMs, and more. If your Custom GPTs were doing anything customer-facing — intake forms, support bots, lead qualification — these platforms are worth the evaluation.

Cost-wise, expect $50–$500/month depending on message volume and features. For a 200-user team, you'll want to run an actual cost model before committing. Stack AI and Dify in particular have been popular in the practitioner community for internal tooling because they support on-prem deployment if your compliance requirements demand it.

How to Audit Your Existing Custom GPTs Before Migrating

Before you start copying system prompts into new tools, do a quick audit. In my experience helping teams with AI workflow migrations, about 30–40% of Custom GPTs in any organization are either unused, duplicative, or so simple they should just become a saved prompt template rather than a dedicated assistant.

  1. Pull usage data first. If you're on a ChatGPT Team or Enterprise plan, check which GPTs have actually been used in the last 30 days. Ruthlessly cut anything with near-zero usage.
  2. Categorize by complexity. Simple (just a system prompt) vs. Medium (system prompt + uploaded files) vs. Complex (system prompt + files + actions/API calls). Simple and Medium migrate easily. Complex ones need more planning.
  3. Interview your power users. Find the 5–10 people using Custom GPTs most heavily and ask what they actually use them for. You'll often discover the real workflow is different from what the GPT was originally designed to do.
  4. Document every system prompt. Export them all to a shared doc right now, today. Don't wait until deprecation cuts access.
Common Mistake: Teams rush to migrate every Custom GPT 1-for-1 into a new platform and end up rebuilding technical debt rather than eliminating it. Use the migration as an opportunity to consolidate. If you have eight GPTs doing slight variations of the same content-writing task, rebuild one well-designed Claude Project instead of eight mediocre ones.

Migration Playbook for Teams of 50+ Users

For business accounts managing multiple users — the exact situation driving this r/ChatGPT thread — the migration needs more than just technical execution. You need change management, or your new tools will gather the same dust your underused Custom GPTs did.

Phase 1: Document & Prioritize (Week 1)

Phase 2: Pilot Migration (Weeks 2–3)

Phase 3: Full Rollout (Weeks 4–6)

Best Practice: Pair each migrated assistant with a one-paragraph "how to use this" guide written in plain language. The single biggest reason Custom GPTs went underused in most orgs wasn't the technology — it was that users didn't know how to prompt them effectively. A brief cheat sheet eliminates 80% of that friction.

What About Prompt-Heavy Marketing Workflows Specifically?

Since a lot of readers here are marketers and advertisers, it's worth calling out where Custom GPTs were genuinely valuable for marketing tasks — and where the alternatives actually improve on them.

Ad copy generation: Custom GPTs with brand voice guides and competitor analysis baked in were popular for PPC and social ad teams. Claude Projects handles this better due to the larger context window — you can include your full brand voice guide, past winning ads, platform specs, and a current brief in a single session. The outputs tend to be more consistent once you dial in the instructions.

Reporting & analysis: If you were using Custom GPTs with data analysis capabilities to interpret campaign performance, the OpenAI Assistants API with Code Interpreter is the proper tool. It lets you upload CSV exports from Google Ads, Meta, or your analytics platform and actually run calculations — not just pattern-match on the text of a spreadsheet.

SOPs and internal knowledge bases: This was the #1 use case I see in marketing agencies — GPTs pre-loaded with internal playbooks so junior team members could get quick answers. Claude Projects or even a simple RAG (retrieval-augmented generation) setup via the Assistants API handles this elegantly, with better citation behavior than Custom GPTs ever offered.

Key Insight: The deprecation of Custom GPTs is accelerating a shift that was already happening in sophisticated marketing teams: moving from "chat interface with a system prompt" to properly-built AI agents that connect to real data sources and take real actions. If your competitors were ahead of you on this, now's your forcing function to catch up.

What to Do Next: Your 5-Step Action Plan

Here's where to start — today, not after the deprecation deadline:

  1. Export everything immediately. Log into ChatGPT, open every Custom GPT you've built, and copy the full system prompt and any uploaded knowledge files to a secure shared location. Don't wait until access is cut off.
  2. Run the usage audit. Check which GPTs are actually being used by your team. Cut the deadweight before you migrate it into your new platform.
  3. Pick your primary migration target. For most teams without dedicated dev resources: ChatGPT Projects (if staying on OpenAI) or Claude Projects (if you want better context handling). For teams with dev resources: evaluate the Assistants API or a platform like Stack AI or Dify.
  4. Migrate your top 3 GPTs first and test with real users. Don't try to move everything at once. Get 3 right, validate them, then expand. Your system prompts will need tweaking — budget for at least 2–3 revision cycles per GPT.
  5. Build a sustainable internal AI directory. A simple page listing "what AI tools we have, what they do, and how to use them" is the difference between a team that uses AI consistently and one that forgets the tools exist 60 days after rollout.

The deprecation of Custom GPTs is genuinely disruptive if you've built your team's AI workflows around them. But the platforms you'll migrate to — particularly Claude Projects, the Assistants API, and the emerging third-party builders — are more capable, more reliable, and more maintainable than Custom GPTs ever were. Treat this as the upgrade it actually is, and you'll come out ahead.

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AI Disclosure: This article was generated with AI assistance based on a community discussion on Reddit r/ChatGPT. Expert analysis and practitioner perspective by John Williams, Founder, AHMEEGO · Google Ads Practitioner with $350M+ in managed Google Ads spend. AI was used to draft and structure the content; all strategic recommendations reflect real campaign experience.