How Much Does It Cost to Build a ChatGPT App?

Wildnet Edge's 2026 cost guide prices a ChatGPT app MVP at $15,000 to $30,000, and that app calls OpenAI's API from your own product. Managed builds of an app that runs inside ChatGPT start from $5,000. The Wildnet Edge figure covers basic retrieval, a standard UI and one data source, puts enterprise builds past $100,000, and leaves you to pay OpenAI's usage fees on top. MCPBundles starts entry projects for managed MCP apps at $5,000 and quotes a full launch with ChatGPT and directory submission after a scoping call.

Those two prices belong to different products. Decide which one you mean before you compare quotes.

Two products called a ChatGPT app

The first lives inside ChatGPT. OpenAI launched apps and the Apps SDK on 6 October 2025 with Booking.com, Canva, Coursera, Expedia, Figma, Spotify and Zillow as pilot partners, and pitched the SDK as a route to over 800 million ChatGPT users. The SDK builds on the Model Context Protocol (MCP). OpenAI has renamed these apps plugins in its developer docs, and each published plugin appears in the universal Plugins Directory shared by ChatGPT and Codex.

The second is your own app or chatbot, on your website or in an app store, that sends requests to OpenAI's API. Customers find it through your channels, and you pay OpenAI for each question and answer. A custom GPT is a third product, and our comparison of custom AI agents and ChatGPT plugins covers that choice.

The parts of an app inside ChatGPT

Harry Brundage at Gadget splits a ChatGPT app into three parts: an MCP server, a protocol extension that renders UI in the conversation, and an optional OAuth 2.1 server. Each part is its own slice of the quote.

• The MCP server. It exposes tools, the actions ChatGPT can call, such as searching a catalogue or checking availability. OpenAI requires a stable public HTTPS endpoint, so you need to host a laptop prototype before review. Choose the domain with care: OpenAI's review rules make you create a new plugin and repeat review if the server's origin changes, a new hostname included.
• The UI, if you want one. The widgets run in sandboxed iframes, and Gadget's team found them slow to configure and hard to debug. The UI needs a content security policy that lists each domain it fetches from.
• The login. In a normal OAuth flow you send users to Google or another provider. Gadget points out the reversal: with a ChatGPT app, your backend becomes the OAuth provider and issues tokens to ChatGPT. OpenAI's authentication docs have ChatGPT run the OAuth code flow with PKCE against your server, and let a read-only app run without login. OpenAI wants you to authenticate users before any tool exposes customer data or writes.

OpenAI's review checklist

Once the app runs in developer mode, the submission work starts. OpenAI's submission guide and review requirements ask for six things:

• A verified publisher. You complete individual verification to publish under your own name, or business verification for a company name. Reviewers may reject a mismatched identity.
• At least five positive and three negative test cases. Each one needs the prompt, the expected behaviour and any test data a reviewer needs to reproduce it.
• A demo account without MFA. Reviewers must log in with no extra setup, and they reject credentials that need SMS codes or email confirmation.
• Accurate tool annotations. Each tool declares readOnlyHint, destructiveHint and openWorldHint. OpenAI counts a tool that sends an email or writes a log as a write.
• A privacy policy that matches your tools. OpenAI asks you to list each user-related field your server returns, remove what the request does not need, and disclose each category of personal data in the policy.
• A public production server, plus a content security policy for any UI.

OpenAI publishes no review timeline. Its docs say timelines may vary and ask developers to skip support requests for a faster review. After launch, OpenAI rescans your tools, and new or changed tools go live once they pass automated checks. If you change the listing or skills, you submit a new version for review.

The cost drivers

The published anchors sit $95,000 apart at the low end. MCPBundles' entry projects begin at $5,000. Launch Day Advisors writes for SaaS and enterprise product teams. It puts a read-only MCP app for one AI client, with 5 to 10 tools, OAuth and audit logging, at $100,000 to $300,000, and an app that takes actions at $300,000 to $700,000. You move along that range with five choices:

• Tool count. You write a schema, annotations and test cases for each tool, and a reviewer must be able to run it with your demo account.
• Reads or writes. For a tool that books, orders or edits data, you set the destructive and open-world flags and write negative tests that prove it refuses the wrong request.
• Login. You can skip OAuth for a public read-only app. Customer accounts and order history mean your backend has to act as the OAuth provider.
• UI. Skip the UI and you skip the iframe, the content security policy and the widget debugging.
• Checkout. OpenAI limits commerce to physical goods in its plugin guidelines and sends buyers to external checkout on your own domain. The embedded Checkout API, with ChatGPT's payment sheet, is in private beta for select marketplaces.

Add the listing work to the quote: test cases, a demo account, a privacy audit and time to resubmit if OpenAI rejects the first version. If you want the same server to serve Claude, Cursor or internal tools, our MCP server cost guide covers that wider build.

Should your business build one this year?

Build one if your customers ask ChatGPT about your category and you have a flow ChatGPT can finish for them: a catalogue to search, a booking to make or a quote to request. OpenAI has written conversion specs for product checkout, restaurant reservations and local-services quote requests, and it is testing the quote flow in beta with approved partners. You need someone who owns the submission, answers rejections and keeps the demo account working.

Wait if nobody asks ChatGPT about what you sell, or if your own website struggles to convert the visitors it has. Fix the site before the app, because OpenAI's rules send buyers to your own domain to check out.

Developer searches have cooled. In our keyword data, US searches for "chatgpt apps sdk" fell from a launch peak of 5,400 in October 2025 to 1,000 in January and 110 in August 2026. Searches for "chatgpt plugin development" rose from 10 to 30 a month over the same stretch, so some developers may have switched to OpenAI's new name. Treat it as a young market and launch with one or two tools before you fund more.

Our AI and automation team scopes these builds from the tools up, and our custom software development work covers the backend and OAuth side.