Free API for Claude Code and Cline: Compatible Providers

Yes, you can run coding agents like Claude Code and Cline using free API providers without paying subscription fees. Verified options include AgentRouter check-in credits, OpenRouter zero-cost model variants, Groq hosted open models, and Google AI Studio Gemini API keys.

Free API providers compatible with coding agents #

Autonomous coding agents require API endpoints capable of processing multi-turn tool calling, structured file edits, and large repository contexts. While commercial frontier models can quickly run up substantial bills during multi-step coding sessions, several verified providers supply free API access suitable for evaluating or augmenting agent workflows.

The leading free API sources verified in our catalog include:

• AgentRouter free credits: AgentRouter is purpose-built for coding assistants like Claude Code, Codex, and Cline. Users earn $25 of credit per daily check-in simply by signing in through GitHub or LinuxDO, allowing real testing on frontier models without an upfront card. See AgentRouter free credits.
• OpenRouter free models: OpenRouter serves dozens of free model endpoints labeled with :free. They include Gemma 4, NVIDIA Nemotron and MiniMax M3.1 Flash, reachable through one OpenAI-compatible API; the offer page lists the current rate limits. See OpenRouter Free AI Models.
• Google Gemini Developer API: Google AI Studio offers developer API keys with extensive free token allowances for Gemini Flash models and Gemini 2.5 Pro. Cline features native Gemini integration, making setup seamless. See Google Gemini Developer API Free Tier.
• Groq Free Tier: Groq delivers hosted open-source models with industry-leading inference speeds. Its OpenAI-compatible endpoint supports agents that need quick responses for code search, summarization, and lightweight refactoring. See Groq Free Tier.
• Token Harbor Free Allowance: Token Harbor grants a weekly rolling allowance covering DeepSeek V4.1 Flash and MiMo V2.6 Flash with zero card required, accessible via its OpenAI-compatible endpoint. See Token Harbor Free Allowance.

How to configure Claude Code with custom free endpoints #

Claude Code is Anthropic's agentic command-line tool. While natively configured for Anthropic Console accounts, you can redirect its underlying network calls to compatible API proxies such as AgentRouter or custom endpoints as outlined in the Anthropic Claude Code documentation.

To route Claude Code through a custom provider:

1. Obtain your API key and base URL from your chosen provider (for example, AgentRouter).
2. Set ANTHROPIC_BASE_URL to the Anthropic-compatible base URL the provider publishes and ANTHROPIC_API_KEY (or ANTHROPIC_AUTH_TOKEN) to its key, as described in the Claude Code settings documentation. An OpenAI-only endpoint does not work here; check that the provider lists Claude Code support.
3. Launch Claude Code by running claude in your project root directory.
4. Verify that the agent successfully initiates and reads repository files without authentication errors.

How to configure Cline with free providers #

Cline is an open-source autonomous coding agent that runs inside VS Code or JetBrains IDEs. Cline provides native drop-down settings for multiple API architectures, as documented in the Cline OpenRouter documentation and Cline OpenAI-compatible documentation.

Follow these steps to configure Cline with a free API:

1. Install the Cline extension from the VS Code Marketplace and open the Cline panel.
2. Click the gear icon in the top header to enter settings.
3. In the API Provider dropdown, select your provider:
   • For OpenRouter: Choose OpenRouter, paste your free API key, and select a model ID ending in :free.
   • For Google Gemini: Choose Google Gemini, paste your key from Google AI Studio, and pick a model the free tier covers (listed on the offer page).
   • For OpenAI-compatible routers (such as Groq or Token Harbor): Select OpenAI Compatible, input the provider's base URL, paste your API key, and specify the target model name.
4. Set your maximum context tokens according to the provider's free ceiling to prevent truncation errors.
5. Save the configuration and initiate a test coding task in your workspace.

Limits and best practices for free agent APIs #

Running coding agents on free API keys differs significantly from simple chat interactions because agents consume tokens rapidly across iterative tool calls:

• Iterative request volume: An agent investigating a bug may read five files, execute two shell commands, and generate three diffs in a single session. This translates to dozens of consecutive API requests, which can rapidly exhaust tight per-minute rate limits.
• Context expansion: As conversation turns accumulate, every request resends the whole conversation, so input tokens grow with each turn. Using models with large context windows (like Gemini 2.5 Flash) helps maintain coherence, but you must monitor provider rate throttles.
• Task scoping: Break complex development tasks into focused, modular sub-tasks. Rather than asking the agent to refactor an entire application, prompt it to modify one function or write a unit test.
• Provider failover: Maintain keys for at least two providers (such as OpenRouter and Gemini). If one endpoint encounters temporary rate limits, you can switch providers immediately and continue development.

Related guides and tools #

• OpenCode free models: If you prefer using OpenCode CLI or desktop with built-in stealth models, see free models in OpenCode.
• Cline setup guide: For an introduction to Cline's interface and workflow, read how to use an AI coding agent for free.
• Coding agent directory: Discover all verified options on the free AI coding tools directory and compare options in free Claude Code alternatives.