Bring Your Own API Key: Cursor vs Windsurf BYOK Reality (2026)
Cursor BYOK is real and unlimited. Windsurf BYOK is restricted. Here is the full picture.
Updated 17 April 2026
# What BYOK Actually Means
"Bring your own key" means you supply an API key from an AI provider (Anthropic, OpenAI, Google, or a local model endpoint) and the IDE routes your requests directly to that provider rather than through the tool's own subscription infrastructure.
💰
Cost control
You pay API rates directly, which can be cheaper or more expensive than subscription depending on usage volume.
🎯
Model choice
Access any model your API key supports, including models not in the tool's standard selection.
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Privacy
With BYOK + privacy mode, requests go direct to the model provider, bypassing the tool vendor's servers entirely.
# Cursor BYOK
Full BYOK support
Pro tier+What you can bring
- + Anthropic API key (Claude Sonnet, Opus, Haiku)
- + OpenAI API key (GPT-5, GPT-4o, o3)
- + Google API key (Gemini 3.1 Pro, Flash)
- + OpenAI-compatible endpoints (Ollama, Groq, etc.)
- + Azure OpenAI endpoints
What BYOK unlocks
- + Unlimited requests (no credit depletion)
- + Models not in Cursor's standard list
- + Privacy mode: requests bypass Cursor servers
- + Local models via Ollama at zero API cost
Setup (Cursor)
Settings (Cmd+,) → Models → Add API Key → Select provider → Enter key. Key is stored locally. Switch between subscription and BYOK per session.
# Windsurf BYOK
Limited BYOK support
EvolvingWindsurf's architecture is more tightly coupled to its own model serving infrastructure than Cursor's. SWE-1.5 runs on Windsurf's Cerebras cluster and cannot be brought externally. The quota billing model works best when routing through Windsurf's servers.
What is supported (April 2026)
- + Partial BYOK via Windsurf settings (check docs)
- - SWE-1.5 NOT available via BYOK (runs on Cerebras)
- - No full bypass of Windsurf routing infrastructure
- - Privacy mode less complete than Cursor
Windsurf's roadmap
Windsurf has acknowledged BYOK demand and has been expanding support. Under Cognition, the roadmap prioritises the SWE-1.5 + Cascade combination over external model flexibility. Check the Windsurf changelog for current status.
# BYOK vs Subscription: The Math
At what usage level does Cursor BYOK become cheaper than the $20 Pro subscription?
| Scenario | Subscription cost | BYOK cost (est.) | Better option |
|---|---|---|---|
| Light use: 10 Sonnet req/day | $20 | ~$5.50 | BYOK |
| Moderate: 30 Sonnet req/day | $20 | ~$16.50 | Either |
| Heavy: 100 Sonnet req/day | $20 + ~$35 overage | ~$55 | Sub (Pro+) |
| Heavy: 100 Opus req/day | $20 + ~$176 overage | ~$176 | Tie |
| Local Ollama (free model) | N/A | $0 | BYOK |
Cost estimates based on Anthropic/OpenAI API rates at ~$3/M tokens in, ~$15/M out for Sonnet; ~$15/M in, ~$75/M out for Opus. Actual rates vary.
# BYOK Comparison Summary
| Feature | Cursor | Windsurf |
|---|---|---|
| Full BYOK support | Yes | Limited |
| OpenAI API key | Yes | Partial |
| Anthropic API key | Yes | Partial |
| Gemini API key | Yes | Partial |
| Local/Ollama endpoint | Yes | No |
| Privacy mode with BYOK | Full bypass | Partial |
| BYOK unlimited requests | Yes | No |
| SWE-1.5 availability | No | Yes (subscription) |
For BYOK power users, Cursor is the clear winner. Windsurf's strength is SWE-1.5 speed, not model flexibility.
# BYOK FAQ
Does Cursor support bring your own API key?+
Does Windsurf support BYOK?+
Is BYOK on Cursor cheaper than the subscription?+
Can I use local models (Ollama) with Cursor?+
What is privacy mode with BYOK on Cursor?+
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