Best LLM Developer Tools in 2026

Promptfoo

Promptfoo helps developers and enterprises evaluate prompts and test AI applications for security risks.

Braintrust

Braintrust is an observability platform for teams improving AI agents that run in production.

LlamaIndex

LlamaIndex helps developers and enterprises process documents and build AI workflows around them.

Opik

Opik helps teams building applications or agents that call an LLM log actions and evaluate behavior through development, testing, and production.

PromptLayer

PromptLayer is a platform for teams that build and improve AI products.

Helicone

Helicone is a platform for routing, debugging, and analyzing AI applications.

LangChain

LangChain is a free, open-source framework for building agents that connect models with tools.

Portkey

Portkey is a platform for managing, observing, and governing generative AI across teams.

CrewAI AMP

Haystack

Haystack is an open-source AI orchestration framework for developers building agents, multimodal applications, advanced retrieval-augmented…

OpenRouter

OpenRouter provides access to hundreds of AI models through a single API endpoint.

Arize Phoenix

Arize Phoenix helps teams trace, evaluate, debug, and improve AI applications.

Replicate

LiteLLM

Hugging Face Inference Endpoints

DSPy

DSPy is a free, MIT-licensed, open-source Python framework for building AI programs and systems.

Fireworks AI

Ragas

Ragas is a free, self-hosted library for systematically evaluating large language model applications.

Cohere North

AutoGen

GroqCloud

Google Gemini API