> For the complete documentation index, see [llms.txt](https://docs.fastrouter.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fastrouter.ai/explore-features.md). # Explore Features - [Dashboard](https://docs.fastrouter.ai/explore-features/quickstart.md): The Dashboard and Activity Log are essential for monitoring, analyzing, and optimizing your API usage with large language models (LLMs). - [Automatic Model Selection](https://docs.fastrouter.ai/explore-features/automatic-model-selection.md) - [Virtual Model Aliases](https://docs.fastrouter.ai/explore-features/virtual-model-aliases.md): Virtual Model Aliases make it easy to manage and optimize amongst multiple LLMs without changing your code. - [FastRouter Blend: Multi-Model Deliberation](https://docs.fastrouter.ai/explore-features/fastrouter-blend-multi-model-deliberation.md): Multi-model deliberation — ask a panel of models the same prompt in parallel, then have a judge model compare their answers into a structured analysis. - [Fallback Models](https://docs.fastrouter.ai/explore-features/fallback-models.md) - [Free Model Router (:free)](https://docs.fastrouter.ai/explore-features/free-model-router.md): FastRouter exposes select models at no charge via the :free slug — up to 10 requests per org per day, with no payment required for organizations having paid credit balance >$1. - [Flex Pricing](https://docs.fastrouter.ai/explore-features/flex-pricing.md): Access OpenAI and Google Gemini models at up to 50% lower cost by opting into flexible inference — ideal for background tasks, batch workloads, and latency-tolerant applications. - [Provider Routing Strategies](https://docs.fastrouter.ai/explore-features/provider-routing-strategies.md) - [Organization & Members](https://docs.fastrouter.ai/explore-features/organization-and-members.md): FastRouter supports role-based access control at the organization level to manage permissions and responsibilities effectively. - [Projects](https://docs.fastrouter.ai/explore-features/projects.md): Projects in FastRouter.ai provide a structure for specifying access and limits for keys used. - [Keys & Settings](https://docs.fastrouter.ai/explore-features/keys-and-settings.md): API keys in FastRouter allow granular control over access, usage, and budget. You can generate multiple keys with custom configurations for different users, projects, or integrations. - [Add External Keys (BYOK)](https://docs.fastrouter.ai/explore-features/add-external-keys-byok.md): Bring Your Own Key — Connect your own provider credentials to FastRouter and route traffic through your own accounts while retaining FastRouter's full routing, observability, and governance layer. - [Custom Evaluations](https://docs.fastrouter.ai/explore-features/custom-evaluations.md): FastRouter's Custom Evaluations lets you benchmark and compare AI models on your own data using LLM-based judges to automatically score accuracy, latency, and cost. - [Dataset Evaluations](https://docs.fastrouter.ai/explore-features/dataset-evaluations.md): FastRouter's Dataset Evaluations let you run a fixed set of test cases against one or more models and score every response with an LLM judge. - [Image Evaluations](https://docs.fastrouter.ai/explore-features/image-evaluations.md): FastRouter's Image Evaluations feature lets you assess the quality of AI-generated images at scale. - [Video Evaluations](https://docs.fastrouter.ai/explore-features/video-evaluations.md): Evaluate AI-generated videos at scale using LLM-based judges, with automated scoring across motion, sync, quality, and prompt adherence. - [Insights](https://docs.fastrouter.ai/explore-features/insights.md): Weekly, evidence-backed recommendations that reduce your LLM spend without giving up output quality. - [Prompt Library](https://docs.fastrouter.ai/explore-features/prompt-library.md): Manage, version, optimize, and deploy prompts independently of your code—enabling instant updates and rollbacks without application redeploys. - [Prompt Optimizations](https://docs.fastrouter.ai/explore-features/prompt-optimizations.md): Automatically refine your system prompts using GEPA — a reflective prompt evolution algorithm that iteratively improves prompts using LLM-judged feedback as gradients. - [Prompt Compression](https://docs.fastrouter.ai/explore-features/prompt-compression.md): Prompt Compression intelligently shrinks prompts before they're sent to an AI model, reducing token usage while maintaining response quality. It helps lower costs and maximize available context. - [Prompt Caching](https://docs.fastrouter.ai/explore-features/prompt-caching.md): FastRouter supports prompt caching on all major providers that offer it, with automatic sticky routing to maximize cache hits. - [Guardrails](https://docs.fastrouter.ai/explore-features/guardrails.md): Add deterministic and LLM-based guardrails to protect your AI applications from unwanted behaviors and ensure compliance. - [Batch Processing](https://docs.fastrouter.ai/explore-features/batch-processing.md): FastRouter supports batch processing for efficient handling of multiple API requests at scale. - [Image Processing](https://docs.fastrouter.ai/explore-features/image-processing.md): A guide to sending images via Base64 or URLs in API requests. - [PDF Processing](https://docs.fastrouter.ai/explore-features/pdf-processing.md): End-to-end guide to PDF ingestion in FastRouter chat completions, including plugin config, request examples, and billing details. - [Dynamic Tags Per Request](https://docs.fastrouter.ai/explore-features/dynamic-tags-per-request.md): Leverage dynamic tags for reporting, billing, or feature tracking with custom tags sent per request. - [Credits](https://docs.fastrouter.ai/explore-features/credits.md) - [Observability Destinations](https://docs.fastrouter.ai/explore-features/observability-destinations.md): Own your observability data. Stream request traces from FastRouter straight into your own Kafka cluster. - [Provisioning Keys](https://docs.fastrouter.ai/explore-features/provisioning-keys.md): Provisioning Keys are special-purpose administrative tokens used to securely create, update, list, and delete Service Account Keys within your organization. - [Structured Outputs](https://docs.fastrouter.ai/explore-features/structured-outputs.md): FastRouter supports structured JSON outputs, allowing you to enforce a specific schema in LLM responses. This feature ensures that responses are machine-readable and conform to a predefined structure. - [Function Calling](https://docs.fastrouter.ai/explore-features/function-calling.md): FastRouter supports Function Calling for models capable of planning and invoking tools or functions. This allows LLMs to return structured function calls instead of natural language responses. - [Reasoning Tokens](https://docs.fastrouter.ai/explore-features/reasoning-tokens.md): FastRouter can return Reasoning Tokens (also known as thinking tokens) for supported models. - [Response Caching: Text](https://docs.fastrouter.ai/explore-features/response-caching.md): This page covers caching for text completions (POST /v1/chat/completions). For image and video generation, see Response Caching: Images & Video (Async). - [Response Caching: Images & Video (Async)](https://docs.fastrouter.ai/explore-features/response-caching-images-and-video-async.md): This page covers caching for asynchronous image generation (POST /api/v1/images/generations) and video generation (POST /api/v1/videos). For text completions, see Response Caching: Text. - [Realtime API (WebSocket)](https://docs.fastrouter.ai/explore-features/realtime-api-websocket.md): Enable real-time speech-to-speech and text conversations with AI models via WebSocket. - [Custom Alerts](https://docs.fastrouter.ai/explore-features/alerts.md): Alerts help you monitor your API usage and performance in real-time. Set up custom thresholds to get notified when metrics exceed expected values or change compared to historical baselines. - [System Alerts](https://docs.fastrouter.ai/explore-features/system-alerts.md): System alerts are automatic, pre-configured notifications that fire when your organization's credit balance or project/key budgets cross critical thresholds - [Tracing](https://docs.fastrouter.ai/explore-features/tracing.md): Group related LLM API calls into a single trace using a simple traceparent header. - [MCP Gateway](https://docs.fastrouter.ai/explore-features/mcp-gateway.md) - [Web Search](https://docs.fastrouter.ai/explore-features/web-search.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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