AI agent builders
We put 8 AI agent builders through the same test. Dust came out on top with 3 out of 5. Here are all the results, what each tool costs and how we test them.
AI agent builders we tested
Best score first. Each one has a full review with the test results, prices and what users say.
Dust
3/5Read our review →
Dify
2.5/5Read our review →
Langflow
2.5/5Read our review →
Voiceflow
2.5/5Read our review →
GPT-trainer
2/5Read our review →
Stack AI
2/5Read our review →
Botpress
2/5Read our review →
GPTBots.ai
2/5Read our review →Test results compared
Every tool got the same test, between October 17, 2026 to October 23, 2026.
| Tool | Score | Runs completed correctly out of 20 | Time to build each workflow from sign-up | How failures are handled (retries, alerts, human hand-off) | Cost per 100 runs at list prices | Integrations available for the workflow without code |
|---|---|---|---|---|---|---|
| Dust | 3/5 | Correct runs 14/20; 14/20; 14/20 | 130 min/agent; 3 agents | Alerts 8/12; hand-off 8/12 | – | 6/10 required connections no-code |
| Dify | 2.5/5 | Correct runs 13/20; 12/20; 12/20 | 137 min/agent; 3 agents | Alerts 7/12; hand-off 7/12 | – | 7/10 required connections no-code |
| Langflow | 2.5/5 | Correct runs 12/20; 12/20; 13/20 | 114 min/agent; 3 agents | Alerts 6/12; hand-off 7/12 | – | 6/10 required connections no-code |
| Voiceflow | 2.5/5 | Correct runs 13/20; 12/20; 12/20 | 145 min/agent; 3 agents | Alerts 7/12; hand-off 8/12 | – | 7/10 required connections no-code |
| GPT-trainer | 2/5 | Correct runs 12/20; 13/20; 12/20 | 163 min/agent; 3 agents | Alerts 8/12; hand-off 8/12 | – | 6/10 required connections no-code |
| Stack AI | 2/5 | Correct runs 13/20; 13/20; 12/20 | 151 min/agent; 3 agents | Alerts 6/12; hand-off 6/12 | – | 6/10 required connections no-code |
| Botpress | 2/5 | Correct runs 12/20; 12/20; 12/20 | 146 min/agent; 3 agents | Alerts 7/12; hand-off 7/12 | – | 5/10 required connections no-code |
| GPTBots.ai | 2/5 | Correct runs 12/20; 12/20; 11/20 | 139 min/agent; 3 agents | Alerts 7/12; hand-off 6/12 | – | 6/10 required connections no-code |
Want just the shortlist?
Our best-of list ranks every tool in this test, with what each one is best for.
What AI agent builders do
Who uses them: Customer support teams, Agencies building agents for clients, Developers prototyping RAG and agent apps, IT and operations teams automating cross-system workflows, Startups that want agents without hiring an ML team.
Price range: Every builder has a free route: Botpress Free, Stack AI Free, Dify Sandbox or free self-hosting, Langflow free software, and a limited Voiceflow free account. Paid self-serve starts around 50 USD a month: Dify Professional 590 USD a year, Voiceflow Pro 60 USD a month, Botpress Plus 150 USD a month on annual billing. Mid tiers run roughly 130 to 750 USD a month (Dify Team 1,590 USD a year, Voiceflow Business 150, Botpress Team 750). Enterprise is by quote everywhere.
What to check before you buy
Use case fit. Voiceflow and Botpress centre on customer support and conversations; Dify and Langflow are general workflow and RAG builders; Stack AI targets internal enterprise workflows.
. Dify (modified Apache 2.0) and Langflow (MIT) can be self-hosted for free; Voiceflow and Stack AI are commercial hosted platforms. Self-hosting gives data control but adds patching and ops work.
Pricing model. Models differ: Voiceflow bills usage credits equal to plan fee, Botpress bills conversation allowances, Dify bills per workspace per year, Langflow is free software plus hosting. Read what counts as a unit before comparing.
Free plan. Botpress Free gives 100 conversations a month, Stack AI Free 500 runs, Dify Sandbox 200 message credits in total, Voiceflow free is not for production.
Security and compliance. Voiceflow lists SOC 2 Type II and ISO 27001; Stack AI lists SOC 2 Type II, ISO 27001 and HIPAA; Dify reports SOC 2 Type II and ISO 27001 but HIPAA is unconfirmed; Botpress SOC 2 status is unclear; Langflow has no vendor certification for self-hosting.
How we test AI agent builders
The test for this category: Build a support agent, a lead-qualification agent and a data-lookup agent; run each 20 times.
Every tool builds the same three workflows (for example: answer support questions from a help centre, qualify a lead and book a call, pull data from a website into a sheet). Each workflow is run 20 times with the same inputs.
Each tool is tested on a paid plan, and its review shows the plan, the price and the test dates. The overall score is the average of the five parts on the right, rounded to the nearest half star. See the full method for AI agents and automation tools.
What we measure
- Runs completed correctly out of 20
- Time to build each workflow from sign-up
- How failures are handled (retries, alerts, human hand-off)
- Cost per 100 runs at list prices
- Integrations available for the workflow without code
The five parts of the score
Frequently asked questions
What is an AI agent builder?
A platform for assembling agents from a model, knowledge and tools using a visual or low-code interface, then publishing them as chat, voice or API.
What is the difference between an agent builder and a chatbot builder?
Agent builders let the model take actions through tools and workflows (refunds, record updates), not only answer questions; Botpress and Voiceflow describe agents that take actions such as refunds and handoffs.
Which AI agent builder is free?
Dify Community and Langflow are free to self-host; Botpress Free (100 conversations), Stack AI Free (500 runs), Dify Sandbox and a limited Voiceflow free account also exist.
Which is best for beginners?
Voiceflow, Botpress and Stack AI are no-code or visual products; Langflow needs Python for customisation and Dify suits technical teams.
How much do AI agent builders cost?
Free to start; paid self-serve from about 50 to 150 USD a month, mid tiers up to 750 USD a month, enterprise by quote.
More in AI chat and agents
Page updated November 4, 2026.
Liam Foster
If there's a strange new AI tool making its way around the internet, I've probably already bookmarked it. My favorite part is figuring out what these platforms can actually do.
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