A Cursor OpenAI compatible API path is now one of the official ways to keep GPT-class models running inside the editor. OpenAI's help center says it plans to wind down the contract that provides OpenAI models to Cursor and has proposed a transition period of November 12, 2026. During that window OpenAI would keep supplying the models Cursor uses today, though Cursor may end access sooner and the companies had not yet published a confirmed end date.
OpenAI lists three options: a direct OpenAI API key, the Codex IDE extension, and an AI gateway reached through a custom OpenAI-compatible base URL. Cursor separately documents bring-your-own-key for OpenAI, Anthropic, Google, Azure, and AWS Bedrock. This post compares those paths with Cursor's built-in models and shows how AtmoRouter fits the gateway slot. Prices come from AtmoRouter's public /v1/models response on November 8, 2026 (Asia/Jakarta) and from OpenAI's and Anthropic's public lists. Rates refresh — treat the models catalogue as authoritative. This is an AtmoRouter-authored comparison, not an independent review.
What each path actually covers
Cursor's built-in models stay on your Cursor plan. They are the only path that covers Cursor Tab, Auto, Cloud or Background Agents, Automations, the Cursor CLI, and Cursor's API and SDK. Both OpenAI and Cursor say bring-your-own keys and gateway credentials apply only to supported local Chat and Agent requests.
A direct vendor key is the simplest BYOK path. You paste an OpenAI, Anthropic, Google, Azure, or Bedrock credential under Cursor Settings > Models, and the provider bills you at its list price. On Cursor's individual plans, those requests do not draw from included usage or prepaid credit. On Teams and Enterprise, Cursor's help pages say a Cursor Token Rate of $0.25 per million tokens (input, output, and cached) can still apply to eligible third-party requests, including ones made with your own key — unless the model's cache-read price is strictly below $0.10 per million tokens across every pricing tier. Cursor also says its Zero Data Retention policy does not apply to BYOK, and that the key is sent to Cursor's backend with each request for final prompt building, then not persisted.
An OpenAI-compatible gateway uses the same OpenAI provider fields, but you override the base URL. OpenAI's help page names Amazon Bedrock, Azure, and "another OpenAI-compatible gateway," and notes that services such as OpenRouter or Vercel AI Gateway may work when the API shape matches what Cursor expects. Compatibility varies, and some model-specific controls may not be forwarded.
The Codex IDE extension is separate again: it adds its own agent panel and does not change the model used by Cursor Chat, Agent, or Tab.
Where the money goes
Built-in Cursor usage is billed through your plan and included credits, so it does not line up against a public per-token list. The fair comparison is vendor API list prices versus a gateway catalogue.
OpenAI's standard list, read on November 8, 2026, prices gpt-6-luna at $0.10 input and $0.50 output per million tokens for short context (up to 272K input tokens; longer prompts cost more) and gpt-5.4-mini at $0.75 / $4.50. Anthropic's public list prices Claude Sonnet 4.6 at $3 / $15.
Lowest listed AtmoRouter tiers the same day (USD per million tokens):
| Path | Model ID | From input / output | Cached input | |---|---|---|---| | Direct OpenAI | gpt-6-luna | $0.10 / $0.50 | $0.01 | | AtmoRouter | oai/gpt-6-luna | $0.01 / $0.05 | $0.001 | | Direct OpenAI | gpt-5.4-mini | $0.75 / $4.50 | $0.075 | | AtmoRouter | oai/gpt-5.4-mini | $0.075 / $0.45 | $0.0075 | | Direct Anthropic | claude-sonnet-4-6 | $3.00 / $15.00 | $0.30 | | AtmoRouter | cc/claude-sonnet-4-6 | $0.60 / $3.00 | $0.06 | | AtmoRouter only | ali/glm-5.3 | $0.028 / $0.088 | $0.0028 |
Higher AtmoRouter tiers exist when the network routes elsewhere. Cached input is billed at 10% of the input rate where the model supports cache. A gateway also lets you call IDs that are not on those vendor lists — for example ali/deepseek-v4-pro-0813 from $0.00165 / $0.00495 — without adding another key in Cursor.
For an illustrative day of 400 coding-agent turns at 12,000 input and 400 output tokens, with no cache: gpt-5.4-mini is about $4.32 at OpenAI's list price and about $0.43 at AtmoRouter's lowest listed tier. The same shape on cc/claude-sonnet-4-6 is about $16.80 at Anthropic's list versus about $3.36 on AtmoRouter. These are arithmetic examples, not a quality benchmark or a promise of the tier you will be billed.
AtmoRouter bills a prepaid balance, charges no seat fees, and does not bill failed requests. Check the pricing page when you top up.
How the OpenAI-compatible path is wired
In Cursor Settings > Models, open the OpenAI provider block:
- 1.Paste your AtmoRouter key from the API Keys page.
- 2.Enable Override OpenAI Base URL and set it to
https://atmorouter.dev/v1— nothttps://atmorouter.dev/v1/chat/completions. Cursor appends the path. - 3.Add the exact catalogue ID, family prefix included (
oai/gpt-5.4-mini, not a marketing name). - 4.Test in local Chat or Agent.
Treat the override as applying to the OpenAI provider path, not as a per-model toggle. If you want Cursor-managed models again, turn it off and confirm with a short test chat.
Prove the key, base URL, and model ID outside Cursor first:
bashcurl https://atmorouter.dev/v1/chat/completions \
-H "Authorization: Bearer $ATMOROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "oai/gpt-5.4-mini",
"messages": [{"role": "user", "content": "Reply with only: cursor-ok"}],
"max_tokens": 20
}'If curl fails, fix the key or model ID before debugging Cursor. If curl works but Cursor does not, check for a missing /v1, a full /chat/completions URL in the override field, or a mismatched model ID.
Which setup to pick
Stay on Cursor's built-in models when you need Tab, Auto, Cloud Agents, or the Cursor CLI, or when your team requires Cursor's Zero Data Retention path. Those features cannot use a gateway key.
Use a direct OpenAI or Anthropic key when you want official vendor billing, organization limits, and those vendors' exact model IDs. You will pay list prices, and on Teams or Enterprise you may also pay Cursor's token rate.
Use an OpenAI-compatible gateway when you want one key, many model families, and lower per-token rates for the Chat and Agent work that BYOK actually covers. That is the slot AtmoRouter is built for: 150+ models on one Chat Completions base URL, with prepaid billing and no seat fees. A mixed setup is normal — keep Tab on Cursor's models, point Chat and Agent at a gateway for volume, and reserve a direct vendor key only if a compliance rule requires it.
FAQ
Does a custom OpenAI-compatible API replace my Cursor subscription?
No. Tab, Auto, Cloud or Background Agents, Automations, the Cursor CLI, and Cursor's API or SDK still use models Cursor supplies or routes.
Will my AtmoRouter key work in the Anthropic provider slot?
This comparison is about Cursor's OpenAI-compatible base URL. Claude Code and the Anthropic SDK use https://atmorouter.dev without /v1 — see the Anthropic-compatible endpoint post. Inside Cursor, you can still add Claude IDs such as cc/claude-sonnet-4-6 through the OpenAI-compatible override.
Does BYOK usage count against Cursor's included credits?
On individual plans, Cursor says no. On Teams and Enterprise, Cursor may still charge its Token Rate on eligible models even when you bring your own key.
Are the prices above guaranteed?
No. They are a snapshot from November 8, 2026. Re-check Models and the vendor price lists before you budget a project.
Next step
If Chat and Agent are the surfaces you care about, create an AtmoRouter key, point Cursor's OpenAI base URL at https://atmorouter.dev/v1, and run the curl check with a cheap ID such as ali/glm-5.3 before you spend on a larger model. The Continue.dev guide and coding agent overview cover the same gateway from other tools.