Free and open first
Best Prompt Engineering Tools in 2026
These tools let you create, organize, test, and refine prompts for AI models. The options here include prompt versioning, playgrounds, automated evaluations, optimization, model-provider support, and deployment integrations.
- 25 apps
- Research read 7 Oct 2026
- How the order is worked out
- 1
Agenta
Free plan Open source APISelf-hostedWebAgenta combines agent-building, automation, and run observability, with both cloud and self-hosted options.
- 2
DeepEval
Free plan Open source APILinuxMac+3DeepEval offers a broad toolkit for evaluating AI systems across modalities, metrics, and agent workflows.
- 3
Giskard
Free plan Open source APILinuxSelf-hosted+1 - 4
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.
- 5
Promptfoo
Free plan Open source APILinuxMac+3Promptfoo combines prompt evaluation with red-team testing and a broad provider and integration list.
- 6
Vellum
Free plan Open source AndroidAPIExtension+5Vellum offers a personal assistant with saved context, skills, integrations and approval controls.
- 7
W&B Weave
Free plan Open source APIiPhoneLinux+4W&B Weave brings tracing, evaluation, monitoring, and safety scoring together for production AI agents.
- 8
TruLens
Free plan Open source APISelf-hostedTruLens offers tracing, evaluation, and version comparison for AI applications, with customizable metrics and self-hosted storage options.
- 9
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.
- 10
Braintrust
Free plan APISelf-hostedWebBraintrust combines production trace inspection with dataset evaluations and prompt iteration.
- 11
ChainForge
Free plan Self-hostedWebChainForge supports structured prompt experiments with comparison, scoring, and plotting features.
- 12
Galileo
Free plan APISelf-hostedWebGalileo combines evaluation, observability, and guardrails with several deployment options and developer interfaces. Check the trace allowance and SSO availability against your deployment needs.
- 13
HoneyHive
Free plan APISelf-hostedWebHoneyHive covers trace inspection, evaluations, live monitoring, and version experiments for AI agents. Teams should compare the free plan’s limits with their event volume and retention needs.
- 14
LangSmith
Free plan APILinuxMac+3LangSmith combines agent evaluation with prompt tools and observability, including cost and trajectory tracking.
- 15
Laminar
Free plan APISelf-hostedWebChoose Laminar if you need OpenTelemetry-native tracing and debugging for AI agents, with evaluations and cloud or self-hosted deployment options.
- 16
MLflow Model Registry
Free plan APILinuxSelf-hosted+1MLflow Model Registry provides versioning, lineage, and lifecycle tools in a free open-source package. Teams that need artifact storage should note that it is not supported.
- 17
Maxim AI
Free plan APISelf-hostedWebMaxim AI brings prompt work, agent evaluation, and production observability into one platform.
- 18
PromptLayer
Free plan APISelf-hostedWebPromptLayer brings prompt editing, evaluation, and operational monitoring into one workflow, with collaboration features for technical and non-technical contributors.
- 19
DSPy
Free plan APISelf-hostedChoose DSPy if you are building AI programs in Python and want task signatures, composable modules, and prompt optimization.
- 20
ProofHound
Free plan APISelf-hostedWebChoose ProofHound for LLM classification workflows that need prompt iteration, auditable experiments, and controlled deployment.
- 21
TextGrad
Free plan LinuxSelf-hostedTextGrad provides a PyTorch-like way to optimize text and other objects using LLM feedback. Its provider keys, experimental engine, and deployment options are important practical considerations.
- 22
PromptTools
Free plan - 23
Amazon Bedrock Prompt Management
Paid WebAmazon Bedrock Prompt Management brings prompt variables, testing, automated optimization, collaboration, and API access into one web service.
4.7 Visit site - 24
Microsoft Foundry Agent Evaluation
Paid Web4.3 Visit site - 25
OpenAI Playground
Paid Web4.2 Visit site
#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
Compare free plans, free trials, open-source licences, and paid starting prices before choosing. Check whether a tool runs self-hosted, on the web, through an API, or on Linux, macOS, or Windows, and confirm that its integrations fit your workflow.
Questions
What are prompt engineering tools used for?
They provide capabilities for managing prompt versions, trying prompts in playgrounds, running automated evaluations, optimizing prompts, connecting model providers, and handling deployment integrations.
Are free prompt engineering tools available?
Yes. The list includes free plans and open-source tools, including Arize Phoenix, DeepEval, ChainForge, and DSPy.
Which tools have open-source code?
ChainForge and DSPy appear in the list as open-source projects. Check the licence before reading, changing, or hosting their code.
Do these tools offer free trials?
Some entries provide trial access at no cost. Check the individual listing for current trial terms.
What platforms do these tools support?
Across the entries, supported environments include self-hosted installations, web applications, APIs, and Linux, macOS, or Windows systems.