> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

Complete SDK documentation and REST API reference for Fiddler AI Observability Platform.

## 🐍 Python Client SDK

### [Python Client SDK](/sdk-api/python-client/connection)

Official Python SDK for comprehensive ML and LLM observability - monitor traditional ML models and LLM applications.

**Key Features:**

* Model onboarding and schema definition
* Production event publishing (batch and streaming)
* Baseline dataset management
* Alert configuration
* Custom metrics and segments

**Use Cases:**

* ML model monitoring (drift, performance, data quality)
* Production data ingestion
* Creating monitoring dashboards
* Configuring alerts for model issues

[**View Full Documentation →**](/sdk-api/python-client/connection)

[**View Usage Guides →**](/developers/python-client-guides/installation-and-setup)

***

## 🎯 Agentic AI SDKs

SDKs for monitoring, evaluating, and testing LLM applications and AI agents.

### [Fiddler Evals SDK](/sdk-api/evals/evaluate)

Evaluate and test LLM outputs with built-in and custom metrics.

**Key Features:**

* Pre-built evaluators (faithfulness, toxicity, coherence, etc.)
* Custom evaluation functions
* Experiment tracking and comparison
* Dataset management for test sets

**Use Cases:**

* LLM output quality assessment
* A/B testing prompts and models
* Regression testing for LLM changes
* Custom evaluation metrics

**Quick Start:**

```python theme={null}
import fiddler as fdl

# Initialize evaluator
evaluator = fdl.AnswerRelevance()

# Run evaluation
result = evaluator.evaluate(
    question="What is Fiddler?",
    answer="Fiddler is an AI observability platform."
)
```

[**View Full Documentation →**](/sdk-api/evals/evaluate)

***

### [Fiddler OTel SDK](/sdk-api/otel/fiddler-client)

Framework-agnostic OpenTelemetry instrumentation for any Python LLM or agent application. This is the foundation the LangChain, LangGraph, and Strands SDKs build on, and the canonical source for Fiddler's span attributes and conversation tracking.

**Key Features:**

* Framework-agnostic tracing for any Python LLM or agent code
* `@trace` decorator and manual span wrappers (chain, generation, tool)
* Conversation and session attribute tracking
* Canonical Fiddler span attributes and span types
* Custom span processor and JSONL capture for offline analysis

**Use Cases:**

* Instrumenting apps not built on LangChain, LangGraph, or Strands
* Adding spans around arbitrary functions and workflows
* Shared tracing primitives across Fiddler's framework SDKs

**Quick Start:**

```python theme={null}
from fiddler_otel import FiddlerClient, trace

# Initialize once at startup (see FiddlerClient reference for options)
client = FiddlerClient()

# Capture a Fiddler span around any function
@trace
def generate_answer(question: str) -> str:
    return call_llm(question)
```

[**View Full Documentation →**](/sdk-api/otel/fiddler-client)

***

### [Fiddler LangGraph SDK](/sdk-api/langgraph/fiddler-client)

[![PyPI](https://img.shields.io/pypi/v/fiddler-langgraph)](https://pypi.org/project/fiddler-langgraph/)

Monitor LangGraph agents with distributed tracing and observability.

**Key Features:**

* Automatic LangGraph instrumentation
* Distributed tracing for agent workflows
* Span attributes for nodes and edges
* Conversation and session tracking

**Use Cases:**

* Debugging multi-step agent workflows
* Performance analysis of agent chains
* Monitoring production LangGraph applications
* Understanding agent decision paths

**Quick Start:**

```python theme={null}
from fiddler.langchain import LangGraphInstrumentor

# Instrument your LangGraph app
instrumentor = LangGraphInstrumentor()
instrumentor.instrument()

# Your LangGraph code runs normally
# Traces are automatically sent to Fiddler
```

[**View Full Documentation →**](/sdk-api/langgraph/fiddler-client)

***

### [Fiddler LangChain SDK](/sdk-api/langchain/fiddler-lang-chain-instrumentor)

Instrument [LangChain V1](https://docs.langchain.com/oss/python/langchain/overview) agents (the `create_agent` API and middleware pattern) and export OpenTelemetry traces to Fiddler.

**Key Features:**

* Automatic instrumentation of LangChain V1 agents
* Drop-in agent middleware emitting LLM, tool, and chain spans
* Retrieval context attachment via `set_llm_context`
* Span and session attribute helpers

**Use Cases:**

* Monitoring production LangChain agents
* Debugging multi-step chains and tool calls
* Tracking retrieval context on LLM spans

**Quick Start:**

```python theme={null}
from fiddler_langchain import FiddlerLangChainInstrumentor

# Call once before creating your agents
FiddlerLangChainInstrumentor().instrument()

# Agents created with langchain.agents.create_agent are now traced
```

[**View Full Documentation →**](/sdk-api/langchain/fiddler-lang-chain-instrumentor)

***

### [Fiddler Strands SDK](/sdk-api/strands/strands-agent-instrumentor)

[![PyPI](https://img.shields.io/pypi/v/fiddler-strands)](https://pypi.org/project/fiddler-strands/)

Monitor Strands Agents with native instrumentation.

**Key Features:**

* Strands Agent instrumentation
* Session and conversation tracking
* Span attributes for agent actions
* Integration with Fiddler platform

**Use Cases:**

* Monitoring Strands production agents
* Debugging Strands Agent workflows
* Tracking agent performance metrics
* Session-based analysis

**Quick Start:**

```python theme={null}
from fiddler.strands import StrandsAgentInstrumentor

# Instrument Strands Agent
instrumentor = StrandsAgentInstrumentor(
    model_id="my-strands-agent"
)
instrumentor.instrument()
```

[**View Full Documentation →**](/sdk-api/strands/strands-agent-instrumentor)

***

### [Fiddler OTel JS SDK](/sdk-api/otel-js/fiddler-client)

OpenTelemetry instrumentation for Fiddler AI observability in TypeScript and JavaScript applications. Captures LLM traces, conversation context, and span attributes.

**Key Features:**

* OpenTelemetry tracing for TypeScript and JavaScript apps
* Isolated tracer provider with OTLP HTTP export to Fiddler
* Manual span helpers (agent, generation, tool)
* Span attribute and token-usage conventions

**Use Cases:**

* Instrumenting Node.js LLM and agent applications
* Capturing traces from non-LangChain TypeScript code
* Adding spans around arbitrary functions and workflows

**Quick Start:**

```typescript theme={null}
import { FiddlerClient } from '@fiddler-ai/otel';

// Initialize once at startup (see FiddlerClient reference for options)
const client = new FiddlerClient();
```

[**View Full Documentation →**](/sdk-api/otel-js/fiddler-client)

***

### [Fiddler LangGraph JS SDK](/sdk-api/langgraph-js/lang-graph-instrumentor)

OpenTelemetry-based instrumentation for LangGraph JS applications. Mirrors the Python `fiddler-langgraph` SDK API for agentic workflows.

**Key Features:**

* Automatic instrumentation of LangGraph JS via the callback manager
* Trace capture for agentic workflows
* Conversation and session attribute tracking
* LLM context helpers

**Use Cases:**

* Monitoring production LangGraph JS agents
* Debugging agent workflows in Node.js
* Conversation- and session-level analysis

**Quick Start:**

```typescript theme={null}
import { LangGraphInstrumentor } from '@fiddler-ai/langgraph';

// Instrument once at startup; LangGraph runs export to Fiddler
new LangGraphInstrumentor().instrument();
```

[**View Full Documentation →**](/sdk-api/langgraph-js/lang-graph-instrumentor)

***

### [Fiddler LangChain JS SDK](/sdk-api/langchain-js/lang-chain-instrumentor)

LangChain JS instrumentation for Fiddler AI observability. Re-exports the callback handler and instrumentor from `@fiddler-ai/langgraph` under a LangChain-branded API, with no code changes to existing chains.

**Key Features:**

* Automatic trace capture for LangChain JS applications
* No changes to existing chains
* Conversation and session attribute tracking
* LLM context helpers

**Use Cases:**

* Monitoring production LangChain JS applications
* Adding observability to existing chains
* Conversation- and session-level analysis

**Quick Start:**

```typescript theme={null}
import { LangChainInstrumentor } from '@fiddler-ai/langchain';

// Instrument once; existing chains are traced with no further changes
new LangChainInstrumentor().instrument();
```

[**View Full Documentation →**](/sdk-api/langchain-js/lang-chain-instrumentor)

***

## 🌐 REST API

### [REST API Reference](/sdk-api/rest-api)

Complete HTTP API documentation for programmatic access to the Fiddler platform.

**Use Cases:**

* Non-Python integrations (Java, Go, JavaScript, etc.)
* Custom CI/CD pipelines
* Integration with existing monitoring systems
* Webhook-based automation

**Quick Start (cURL):**

```bash theme={null}
# Publish events to Fiddler
curl -X POST https://app.fiddler.ai/api/v1/events 
  -H "Authorization: Bearer fid_..." 
  -H "Content-Type: application/json" 
  -d '{
    "project": "fraud-detection",
    "model": "fraud_model_v1",
    "events": [...]
  }'
```

[**View Full REST API Documentation →**](/sdk-api/rest-api)

**API Guides:**

* [Alert Rules](/sdk-api/rest-api/alert-rules)
* [Applications](/sdk-api/rest-api/applications)
* [Attributes](/sdk-api/rest-api/attributes)
* [Baselines](/sdk-api/rest-api/baseline)
* [Custom Metrics](/sdk-api/rest-api/custom-metrics)
* [Environments](/sdk-api/rest-api/environment)
* [Evals](/sdk-api/rest-api/evals)
* [Evaluation](/sdk-api/rest-api/evaluation)
* [Evaluator Rules](/sdk-api/rest-api/evaluator-rules)
* [Evaluators](/sdk-api/rest-api/evaluators)
* [Events](/sdk-api/rest-api/events)
* [Experiments](/sdk-api/rest-api/experiments)
* [File Upload](/sdk-api/rest-api/file-upload)
* [FQL Expressions](/sdk-api/rest-api/fql-expressions)
* [GenAI Alert Rules](/sdk-api/rest-api/genai-alert-rules)
* [Jobs](/sdk-api/rest-api/jobs)
* [LLM Gateway](/sdk-api/rest-api/llm-gateway)
* [Models](/sdk-api/rest-api/model)
* [Projects](/sdk-api/rest-api/projects)
* [Queries](/sdk-api/rest-api/queries)
* [Segments](/sdk-api/rest-api/segments)
* [Server Info](/sdk-api/rest-api/server-info)
* [Spans](/sdk-api/rest-api/spans)
* [User Access Keys](/sdk-api/rest-api/user-access-keys)
* [Users](/sdk-api/rest-api/users)

### [Guardrails API Reference](/sdk-api/guardrails-api-reference)

API endpoints for Fiddler guardrails.

***

## 🚀 Getting Started

### Choose Your SDK

| Your Use Case                                | Recommended SDK                                                             |
| -------------------------------------------- | --------------------------------------------------------------------------- |
| **Monitor ML/LLM models and platform admin** | [Python Client SDK](/sdk-api/python-client/connection)                      |
| **Evaluate and test LLM outputs**            | [Fiddler Evals SDK](/sdk-api/evals/evaluate)                                |
| **Instrument any Python LLM/agent app**      | [Fiddler OTel SDK](/sdk-api/otel/fiddler-client)                            |
| **Monitor LangGraph (Python) agents**        | [Fiddler LangGraph SDK](/sdk-api/langgraph/fiddler-client)                  |
| **Monitor LangChain (Python) agents**        | [Fiddler LangChain SDK](/sdk-api/langchain/fiddler-lang-chain-instrumentor) |
| **Monitor Strands agents**                   | [Fiddler Strands SDK](/sdk-api/strands/strands-agent-instrumentor)          |
| **Instrument any TypeScript/JS app**         | [Fiddler OTel JS SDK](/sdk-api/otel-js/fiddler-client)                      |
| **Monitor LangGraph JS apps**                | [Fiddler LangGraph JS SDK](/sdk-api/langgraph-js/lang-graph-instrumentor)   |
| **Monitor LangChain JS apps**                | [Fiddler LangChain JS SDK](/sdk-api/langchain-js/lang-chain-instrumentor)   |
| **Language-agnostic HTTP integration**       | [REST API](/sdk-api/rest-api)                                               |

### Installation

**Python SDKs:**

```bash theme={null}
# Python Client SDK
pip install fiddler-client

# Evals SDK
pip install fiddler-evals

# OTel SDK (framework-agnostic instrumentation)
pip install fiddler-otel

# LangGraph SDK
pip install fiddler-langgraph

# LangChain SDK
pip install fiddler-langchain

# Strands SDK
pip install fiddler-strands
```

<Note>
  Fiddler follows the Python Software Foundation's support schedule for Python versions. See the [Python version support policy](/reference/python-support-policy) for details.
</Note>

**JavaScript / TypeScript SDKs:**

```bash theme={null}
# OTel JS SDK
npm install @fiddler-ai/otel

# LangGraph JS SDK
npm install @fiddler-ai/langgraph

# LangChain JS SDK
npm install @fiddler-ai/langchain
```

**REST API:** No installation required - use any HTTP client.

***

## 📚 Related Documentation

* [**Developer Guides**](/developers/quick-starts/get-started-in-less-than-10-minutes) - Quick starts and tutorials
* [**Integrations**](/integrations) - Connect with your ML stack
* [**Product Documentation**](/) - Platform features and concepts

***

## 💡 Common Workflows

### ML Model & LLM App Monitoring Workflow

1. Install [Python Client SDK](/sdk-api/python-client/connection)
2. Define [model schema](/sdk-api/python-client/model-schema)
3. Upload [baseline dataset](/sdk-api/python-client/baseline)
4. [Publish production events](/sdk-api/rest-api/events)
5. Configure [alerts](/sdk-api/python-client/alert-rule)

### LLM Experiments Workflow

1. Install [Fiddler Evals SDK](/sdk-api/evals/evaluate)
2. Create a test dataset with the [Dataset API](/sdk-api/evals/dataset)
3. Define evaluators ([built-in](/sdk-api/evals/evaluator) or [custom](/sdk-api/evals/eval-fn))
4. Run [experiments](/sdk-api/evals/experiment) and analyze results

### Agent Monitoring Workflow

1. Install the SDK for your framework — [LangGraph](/sdk-api/langgraph/fiddler-client), [LangChain](/sdk-api/langchain/fiddler-lang-chain-instrumentor), [Strands](/sdk-api/strands/strands-agent-instrumentor), or a JavaScript SDK ([OTel JS](/sdk-api/otel-js/fiddler-client), [LangGraph JS](/sdk-api/langgraph-js/lang-graph-instrumentor), [LangChain JS](/sdk-api/langchain-js/lang-chain-instrumentor))
2. Instrument your agent application
3. Deploy to production
4. View traces and analytics in the Fiddler platform

***

## 📖 Additional Resources

* [**GitHub Examples**](https://github.com/fiddler-labs/fiddler-examples) - Sample code and notebooks
* [**SDK Changelog**](/changelog/python-sdk) - Latest SDK updates
* [**Support Portal**](mailto:support@fiddler.ai) - Enterprise support
* [**Community**](https://fiddler-community.slack.com) - Join our Slack community