Does this work without an Anthropic account?

Yes. LLMsRelay is an independent Claude API gateway. You do not need an Anthropic account, no phone verification — just sign up at llmsrelay.com and generate a key.

Which Cursor plan do I need to use a custom Claude API key?

Cursor requires a paid Pro plan or higher to enable custom OpenAI-compatible endpoints. The 7-day Pro trial does NOT unlock this — you must be on a paid Cursor subscription.

Can I use Tab completion with Claude through LLMsRelay?

Tab completion in Cursor uses Cursor's own model and is not configurable. Chat, Composer, inline edits, and Agent mode all work with Claude via LLMsRelay.

Which Claude model is best for Cursor coding?

Claude Sonnet 4.6 is the default daily-driver — best balance of speed and quality. Use Opus 4.7 for complex refactors and architecture decisions, Haiku 4.5 for fast batch edits.

What is the Base URL for Cursor when using LLMsRelay?

https://api.llmsrelay.com/v1 — this is the OpenAI-compatible endpoint. It must include /v1 at the end. Do not use https://api.llmsrelay.com directly in Cursor — that is the Anthropic-format endpoint.

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How to Use Claude API in Cursor IDE — 2-Minute Setup [2026]

Connect Claude Sonnet 4.6, Opus 4.7, and Haiku 4.5 to Cursor IDE via LLMsRelay. Step-by-step guide, no Anthropic account. Works with Chat, Composer, and Agent.

LLMsRelay is an independently operated API gateway. It is not affiliated with or endorsed by Anthropic, PBC. Product and model names are used only to describe compatibility.

Quick Answer

To use Claude API in Cursor IDE: open Cursor Settings → Models, enable OpenAI API Key and OpenAI Base URL, set the base URL to https://api.llmsrelay.com/v1, paste your LLMsRelay API key, and add claude-sonnet-4.6 to the model list. Setup takes under 2 minutes. No Anthropic account, no phone verification — just a Cursor Pro subscription and a LLMsRelay key.

Why LLMsRelay for Cursor?

Cursor's built-in Claude access requires Anthropic's API key, which has account requirements, no Russian/CIS payment options, and limited per-key controls. LLMsRelay solves all three: instant signup, payment in RUB/crypto/cards, and per-key credit limits.

Same Claude models (Sonnet 4.6, Opus 4.7, Haiku 4.5) — same per-token rates as Anthropic direct
OpenAI-compatible endpoint — Cursor sees it as a generic OpenAI proxy
Pay with Mir card, SBP, USDT, BTC, or international Visa/Mastercard
Per-key credit limits — set $20 cap on a key for a junior dev, no surprise bills

Required Plan

Custom API access in Cursor requires a paid Pro plan or higher.

Pro trial (7 days) does not unlock custom API endpoints. You must be on a paid Cursor subscription before connecting LLMsRelay.

Exact Fields in Cursor

OpenAI API Key: your API key from the LLMsRelay dashboard (starts with sk-)
OpenAI Base URL: https://api.llmsrelay.com/v1 (must include /v1)
Verify: click "Verify" — Cursor will list all available models

Recommended Setup

Open Cursor settings (Cmd/Ctrl + ,)
Go to Models
Turn on OpenAI API Key
Paste your API key from llmsrelay.com dashboard
Turn on OpenAI Base URL
Set it to https://api.llmsrelay.com/v1
Click Verify — should show "OpenAI key works"
Open Composer (Cmd/Ctrl + I), pick a Claude model from the dropdown, send a test prompt

Use the OpenAI-compatible path, not Anthropic mode. The base URL for Cursor includes /v1 at the end.

Recommended Model IDs

claude-opus-4.7 — most powerful, best for refactors and architecture
claude-sonnet-4.6 — best value for daily coding (default)
claude-haiku-4.5 — fastest, cheapest, ideal for batch edits

Troubleshooting

"Invalid API Key" error: Verify the key starts with sk- and the base URL ends with /v1. Cursor caches keys aggressively — restart Cursor after pasting.

"Model not found": Make sure the model ID exactly matches (e.g. claude-sonnet-4.6, not claude-sonnet-4.5). Add the model in Cursor's "Add Model" field.

Slow responses: Switch to Haiku 4.5 for fast inline edits, or check your network. LLMsRelay adds <100ms overhead vs Anthropic direct.

Windows-specific notes

The 8-step setup above is identical on Windows, macOS, and Linux. A few Windows extras:

Installer: download Cursor from cursor.sh. The MSI puts cursor on PATH and registers %APPDATA%\Cursor for settings.
Hotkey: Ctrl+, for Settings, Ctrl+I for Composer, Ctrl+L for Chat.
Restart Cursor fully after pasting the key — close all windows, then end any Cursor.exe in Task Manager. Cursor caches OpenAI credentials in memory.
Corporate proxy: setx HTTPS_PROXY "http://proxy.company:8080" in PowerShell, then reopen Cursor.
SmartScreen / antivirus blocking outbound calls — whitelist api.llmsrelay.com.
WSL projects: Cursor on Windows talks to LLMsRelay directly — env vars inside WSL do not affect Cursor's HTTP calls. Configure the key in Cursor Settings (the GUI), not in ~/.bashrc.

Ready to start?

Create a key and configure a compatible API route in under 2 minutes.

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