Free and open first
Best Llm Developer Tools in 2026
Use this list to compare software for working with large language models (LLMs). Options run through APIs, web apps, self-hosted deployments, Linux, macOS, and Windows.
- 26 apps
- Research read 7 Oct 2026
- How the order is worked out
- 1
DeepEval
Free plan Open source APILinuxMac+3DeepEval offers a broad toolkit for evaluating AI systems across modalities, metrics, and agent workflows.
- 2
Langfuse
Free plan Open source APILinuxSelf-hosted+1Langfuse brings tracing, prompt workflows, and evaluation features into one AI engineering platform, with both hosted and self-hosted options.
- 3
Opik
Free plan Open source APILinuxMac+3Opik brings tracing, evaluation, testing, and production monitoring into one platform, with both cloud and self-hosted options.
- 4
Promptfoo
Free plan Open source APILinuxMac+3Promptfoo combines prompt evaluation with red-team testing and a broad provider and integration list.
- 5
Arize Phoenix
Free plan APISelf-hostedWebPhoenix brings tracing, evaluation, prompt inspection, and dataset experiments to AI application teams. It is free and open source, with deployment choices and usage management left to users.
- 6
Braintrust
Free plan APISelf-hostedWebBraintrust combines production trace inspection with dataset evaluations and prompt iteration.
- 7
CrewAI AMP
Free plan APISelf-hostedWebChoose CrewAI AMP if your team needs several ways to build multi-agent workflows alongside tracing and governance controls.
- 8
Helicone
Free plan APISelf-hostedWebHelicone brings routing and observability tools together, with a free tier and self-hosting options. Its maintenance-mode status is worth weighing when considering it for a new deployment.
- 9
LangSmith
Free plan APILinuxMac+3LangSmith combines agent evaluation with prompt tools and observability, including cost and trajectory tracking.
- 10
LlamaIndex
Free plan APILinuxSelf-hosted+1LlamaIndex combines document parsing, extraction, classification, and retrieval pipelines for teams building document-centered AI workflows.
- 11
Haystack
Free plan APISelf-hostedHaystack provides a free framework for assembling AI systems from modular pipelines, with integrations and self-hosted deployment options.
- 12
LangChain
Free plan APISelf-hostedChoose LangChain to build agents around models and tools using its configurable harness, middleware, and wide range of integrations.
- 13
LiteLLM
Free plan APISelf-hostedWebChoose LiteLLM if your platform team needs a shared gateway for many providers, with routing and spend controls.
- 14
DSPy
Free plan APISelf-hostedChoose DSPy if you are building AI programs in Python and want task signatures, composable modules, and prompt optimization.
- 15
Portkey
Free plan APISelf-hostedWebPortkey brings model access, prompt management, and activity monitoring under one platform. Review the plan's log retention, deployment, and support terms against your team's requirements.
- 16
OpenRouter
Free plan APIWebOpenRouter brings model access, routing and integrations together behind a single endpoint. The Free plan has a daily request cap, while pay-as-you-go plans apply platform fees to credit purchases.
- 17
PromptLayer
Free plan APISelf-hostedWebPromptLayer brings prompt editing, evaluation, and operational monitoring into one workflow, with collaboration features for technical and non-technical contributors.
- 18
Replicate
Free plan APIWeb6.6 Visit site - 19
Ragas
Free plan APILinuxSelf-hostedRagas offers a broad evaluation toolkit for LLM applications, from synthetic test data through production monitoring.
- 20
AutoGen
Free plan LinuxMacWindows - 21
Google Gemini API
Free plan Web - 22
GroqCloud
Free plan Web - 23
Cohere North
Paid Self-hostedWebNorth combines enterprise search, agent automation, natural-language application building, and deployment flexibility. Its custom pricing and enterprise focus make sales consultation part of adoption.
- 24
Fireworks AI
Paid APISelf-hostedWeb5.7 Visit site - 25
Hugging Face Inference Endpoints
Paid APIWeb
#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
Check free-plan limits, trial terms, paid starting prices, deployment choices, supported LLM providers, evaluation and observability features, SDK languages, and open-source licences. If you need to read or change code, review the licence before choosing.
Questions
Are free LLM developer tools available?
Yes. Items such as Arize Phoenix, AutoGen, DeepEval, DSPy, Google Gemini API, GroqCloud, and Haystack list a free plan or open-source access.
Do these tools offer free trials?
Trial terms vary. Helicone lists a 7-day trial. Check the individual tool's pricing details for current trial conditions.
Can I self-host an LLM developer tool?
Yes. Self-hosted deployment is a platform option in this category. Cohere North and Fireworks AI list self-hosted support.
Which comparison fields matter for LLM tools?
Compare free plan, paid-from price, deployment, LLM providers, LLM evaluation, LLM observability, SDK languages, and open-source status.
What does open source mean here?
Open-source code is offered by tools such as DSPy and Haystack. Read the licence to confirm what use, changes, and distribution are allowed.