AI Tools
Best Llm Developer Tools in 2026
LLM developer tools help build, evaluate, and monitor applications that use language models. This list lets you assess pricing, deployment options, model-provider coverage, SDK languages, evaluation, observability, and open-source status.
- 01
DeepEval DeepEval suits developers building evaluation pipelines for AI systems, particularly those who want tests to run in CI/CD or Python scripts.
From $200/mo Free plan Open source Web · Windows · macOS · Linux9.3 Visit Specs - 02
Braintrust Braintrust is aimed at teams operating AI agents in production, from early-stage teams to enterprises.
From $249/mo Free plan Web · API · Self-hosted9.2 Visit Specs - 03
LangSmith LangSmith suits teams engineering AI agents that need evaluation, tracing, prompt work, deployment, and production monitoring.
From $39/mo Free plan Web · Windows · macOS · Linux9.0 Visit Specs - 04
Langfuse Langfuse suits teams building AI agent applications that need tracing, prompt management, and evaluation tools.
From $29/mo Free plan Open source Web · Linux · API · Self-hosted8.9 Visit Specs - 05
Opik Opik suits teams developing applications or agents that make calls to an LLM and want tracing and evaluation across the development cycle.
From $19/mo Free plan Open source Web · Windows · macOS · Linux8.8 Visit Specs - 06
Promptfoo It suits developers and enterprises evaluating prompts or testing AI applications for risks.
Free plan Open source Web · Windows · macOS · Linux8.3 Visit Specs - 07 Arize Phoenix
It suits teams operating AI applications that need model, retrieval, tool, prompt, and evaluation tracing.
Free plan Web · API · Self-hosted8.2 Visit Specs - 08
Haystack Haystack is built for AI developers and engineers creating modular, transparent systems, including agent workflows, RAG and multimodal applications.
Free plan API · Self-hosted8.1 Visit Specs - 09
Helicone Helicone suits teams routing and observing AI application requests across model providers, including teams that need self-hosting or LLM cost tracking.
From $79/mo Free plan Web · API · Self-hosted8.1 Visit Specs - 10
LangChain It suits developers building configurable model-and-tool agents in Python or JavaScript/TypeScript.
From $39/mo Free plan API · Self-hosted8.1 Visit Specs - 11 CrewAI AMP Free plan Web · API · Self-hosted8.0 Visit Specs
- 12 Portkey
Portkey suits teams that need a common API and operational controls for generative AI models and providers.
From $49/mo Free plan Web · API · Self-hosted8.0 Visit Specs - 13
PromptLayer PromptLayer is for engineers and domain experts who build or improve AI products together.
From $49/mo Free plan Web · API · Self-hosted7.6 Visit Specs - 14 Cohere North Web · Self-hosted7.5 Visit Specs
- 15 DSPy API · Self-hosted7.5 Visit Specs
- 16
LiteLLM LiteLLM is aimed at platform teams that need a shared gateway, model routing and spend controls.
Free plan Web · API · Self-hosted7.5 Visit Specs - 17
LlamaIndex LlamaIndex suits developers and enterprises building document-processing, retrieval and knowledge-work workflows.
From $50/mo Web · Linux · API · Self-hosted7.5 Visit Specs - 18
OpenRouter Free plan Web · API7.5 Visit Specs - 19
Fireworks AI Web · API · Self-hosted7.4 Visit Specs - 20
Hugging Face Inference Endpoints From $0.06/mo Web · API7.4 Visit Specs - 21 Replicate Free plan Web · API7.3 Visit Specs
- 22
Ragas Linux · API · Self-hosted7.1 Visit Specs - 23 AutoGen Windows · macOS · Linux6.2 Visit Specs
- 24 Google Gemini API Web5.7 Visit Specs
- 25 GroqCloud Web5.7 Visit Specs
When selecting a tool, see if its free plan or trial suits your work, note the starting paid price, and confirm availability on the needed platform: API, web, self-hosted, Linux, macOS, or Windows.