PR #29184: feat(OpenAI Chat Model Node): Add OpenAI account OAuth support

• Repository: n8n-io/n8n
• Author: EtienneLescot
• State: open | merged: False
• Link: https://github.com/n8n-io/n8n/pull/29184

Description (problem / solution / changelog)

Summary

Add OpenAI account OAuth support to the OpenAI Chat Model node while keeping the existing API key credential path unchanged.

This adds a dedicated OpenAI Account (ChatGPT) credential and lets the OpenAI Chat Model node choose between API key and OAuth2 authentication. The OAuth2 credential stays aligned with n8n's existing credential UX: users still use the standard Connect button and popup/BroadcastChannel flow, while the popup hosts OpenAI's device-code login flow instead of asking users to paste an access token manually.

OpenAI account tokens cannot call the public OpenAI Responses API directly, so OAuth-backed chat model execution uses the ChatGPT/Codex account backend and maps LangChain messages, streaming chunks, tool calls, tool results, model discovery, and reasoning effort into that protocol. API key execution continues to use the existing OpenAI/LangChain path.

OpenAI-specific credential UI is kept small: the OAuth redirect URL and HTTP Request domain restriction controls are hidden for this credential because they do not apply to the device-code flow.

Related Linear tickets, Github issues, and Community forum posts

• Related to #29180
• Community forum: https://community.n8n.io/t/feature-oauth2-support-for-openai-chatgpt/285451
• Docs follow-up: https://github.com/n8n-io/n8n-docs/issues/4526
• Docs PR: https://github.com/n8n-io/n8n-docs/pull/4527

No Linear ticket is linked because this is an external contribution and I do not have access to the n8n Linear workspace. The GitHub issue was auto-closed because n8n uses GitHub issues for bugs only, but it is kept here as public context for this contribution.

Review / Merge checklist

• I have seen this code, I have run this code, and I take responsibility for this code.
• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with Backport to Beta, Backport to Stable, or Backport to v1 (if the PR is an urgent fix that needs to be backported)

Validation

• pushd packages/nodes-base && pnpm test OpenAiApi.credentials.test.ts --runInBand && popd
• pushd packages/@n8n/nodes-langchain && pnpm test LmChatOpenAi.test.ts OpenAiAccountChatModel.test.ts LMChatOpenAi/methods/__tests__/loadModels.test.ts --runInBand && popd
• pushd packages/cli && pnpm test openai-oauth2-device.controller.test.ts oauth2-credential.controller.test.ts load-nodes-and-credentials.test.ts --runInBand && popd
• pushd packages/frontend/editor-ui && pnpm vitest run src/features/credentials/components/CredentialEdit/CredentialEdit.test.ts src/features/credentials/components/CredentialEdit/CredentialConfig.test.ts && popd
• pushd packages/nodes-base && NODE_OPTIONS=--max-old-space-size=8192 pnpm lint && popd
• pushd packages/@n8n/nodes-langchain && pnpm lint && popd
• pushd packages/cli && NODE_OPTIONS=--max-old-space-size=8192 pnpm lint && popd
• pushd packages/frontend/editor-ui && pnpm lint && popd
• pushd packages/cli && NODE_OPTIONS=--max-old-space-size=8192 pnpm typecheck && popd
• pushd packages/@n8n/nodes-langchain && pnpm typecheck && popd
• pushd packages/nodes-base && pnpm typecheck && popd
• pushd packages/frontend/editor-ui && pnpm typecheck && popd
• pnpm build > build.log 2>&1
• git diff --check origin/master..HEAD
• Manual local startup and workflow test with OAuth credential on http://localhost:5680

Changed files

• packages/@n8n/nodes-langchain/nodes/llms/LMChatOpenAi/LmChatOpenAi.node.ts (modified, +170/-38)
• packages/@n8n/nodes-langchain/nodes/llms/LMChatOpenAi/OpenAiAccountChatModel.ts (added, +1389/-0)
• packages/@n8n/nodes-langchain/nodes/llms/LMChatOpenAi/methods/__tests__/loadModels.test.ts (modified, +62/-0)
• packages/@n8n/nodes-langchain/nodes/llms/LMChatOpenAi/methods/loadModels.ts (modified, +98/-3)
• packages/@n8n/nodes-langchain/nodes/llms/test/LmChatOpenAi.test.ts (modified, +107/-0)
• packages/@n8n/nodes-langchain/nodes/llms/test/OpenAiAccountChatModel.test.ts (added, +388/-0)
• packages/cli/src/__tests__/load-nodes-and-credentials.test.ts (modified, +13/-1)
• packages/cli/src/auth/__tests__/auth-service-browser-id-whitelist.test.ts (modified, +6/-0)
• packages/cli/src/auth/auth.service.ts (modified, +1/-0)
• packages/cli/src/controllers/oauth/__tests__/oauth2-credential.controller.test.ts (modified, +21/-0)
• packages/cli/src/controllers/oauth/__tests__/openai-oauth2-device.controller.test.ts (added, +136/-0)
• packages/cli/src/controllers/oauth/oauth2-credential.controller.ts (modified, +14/-0)
• packages/cli/src/controllers/oauth/openai-oauth2-device.controller.ts (added, +457/-0)
• packages/cli/src/load-nodes-and-credentials.ts (modified, +4/-0)
• packages/cli/src/server.ts (modified, +1/-0)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialEdit/CredentialConfig.test.ts (modified, +33/-0)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialEdit/CredentialConfig.vue (modified, +5/-1)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialEdit/CredentialEdit.test.ts (modified, +88/-0)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialEdit/CredentialEdit.vue (modified, +7/-0)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialIcon.test.ts (modified, +29/-0)
• packages/frontend/editor-ui/src/features/credentials/components/CredentialIcon.vue (modified, +6/-0)
• packages/nodes-base/credentials/OpenAiApi.credentials.ts (modified, +25/-1)
• packages/nodes-base/credentials/OpenAiOAuth2Api.credentials.ts (added, +83/-0)
• packages/nodes-base/credentials/test/OpenAiApi.credentials.test.ts (modified, +114/-17)
• packages/nodes-base/package.json (modified, +1/-0)
• packages/workflow/src/interfaces.ts (modified, +2/-0)