# Best AI agent builders (Voiceflow, Botpress, Relevance AI, Zapier Agents)

> Voiceflow for CX teams shipping customer-facing chat agents with real governance. Botpress for developers who want an escape hatch to code. Relevance AI for business teams building fleets of worker agents. Zapier Agents if your automations already live in Zapier: automation with AI inside, not an agent platform.

Human page: https://testedactually.com/ai-agent-builders/
Mirror: https://testedactually.com/ai-agent-builders.md
Updated: 2026-09-20

## Picks

- **Voiceflow** — best for CX teams shipping customer-facing chat agents with approvals and versioning. Don't use it if you want autonomous background agents, Voiceflow is conversation-first
- **Botpress** — best for developers who want depth, on-prem options, and an actual code escape hatch. Don't use it if you want the slickest marketing-friendly UI, Botpress trades polish for power
- **Relevance AI** — best for business teams building fleets of agents on top of company data. Don't use it if you need a simple chatbot this week, Relevance builds worker agents and expects process thinking
- **Zapier Agents** — best for teams already living in Zapier who want agents over 9,000+ app connections. Don't use it if you need sophisticated reasoning loops, it is automation with AI inside rather than an agent platform

**AI agent builders — compared**

| Tool | Free tier | Paid from | No-code builder | Knowledge (RAG) | Multi-agent teams | AI crawlers |
| --- | --- | --- | --- | --- | --- | --- |
| [Voiceflow](/ai-agent-builders/voiceflow/) | Free plan with one agent and limits | $60/mo | Yes, visual dialogue designer | Yes, knowledge base with API sync | No, single-agent conversation workflows | open |
| [Botpress](/ai-agent-builders/botpress/) | Free plan, 25 conversations per month, no top-ups | $150/mo | Yes, visual studio plus code hooks | Yes, knowledge bases per agent | Yes, autonomous nodes in workflows | open |
| [Relevance AI](/ai-agent-builders/relevance-ai/) | Free plan with monthly credits | $19/user/mo | Yes, tool and agent builders | Yes, agents work over your data and tools | Yes, agent fleets with org roles | open |
| [Zapier Agents](/ai-agent-builders/zapier-agents/) | Available on Zapier plans, limits apply | $0/mo | Yes, chat and behaviour setup | Yes, connect data sources and apps | No, one agent per task today | open |

## Don't use it if

- **Zapier Agents**: you need multi-step reasoning loops and agent collaboration, it is one agent per task today.
- **Relevance AI**: you want a support chatbot live this week, it builds worker agents and expects process design.
- **Botpress**: your team is purely non-technical, the power comes with developer-shaped surfaces.

## Demo-ware versus shipped

Agent builders are the most demo-driven category in AI right now, so our
test is boring and decisive: can a non-engineering team ship this to real
customers with governance (versioning, approvals, handovers) and keep it
alive? Voiceflow is built for that week. Botpress assumes a developer in the
loop and rewards them. Relevance AI asks you to design work like a process
owner. Zapier Agents is the fastest to first value and the first ceiling.

## Knowledge is the real feature

Every builder claims RAG. The differences that matter: how knowledge syncs
(notice when it goes stale), how answers cite their sources, and what
happens when knowledge is missing (silence beats hallucination for business
use). We score the column honestly and name the mechanism where the vendor
publishes one.

## Original data

This category generates more hype than any other we cover, which is exactly
why we run original, dated benchmarks (crawler access across these vendors,
methodology on the benchmark page) instead of republishing launch-week
articles. If a vendor's pricing page cannot be read by an answer engine
today, that fact is in our data.

## What we did not test

We have not measured agent task-completion rates on a standard task suite,
which is the benchmark this category needs and conventional agent benchmarks
do not provide for business use. It is scoped and on the roadmap. Until
then: our tables cover facts with sources, not vibes with adjectives.

## FAQ

### What is the best AI agent builder?

Voiceflow for customer-facing chat agents shipped by CX teams, Botpress for developer depth and on-prem options, Relevance AI for business teams building agent fleets over company data, and Zapier Agents for teams already standardised on Zapier.

### Can I build an AI agent without coding?

Yes on all four platforms in this comparison. The honest differences are ceilings; Voiceflow and Zapier Agents are comfortable no-code, Botpress and Relevance AI start no-code and reward code when you outgrow the visual tools.

### Which agent builders support multi-agent teams?

Relevance AI builds agent fleets as a first-class concept, and Botpress supports autonomous nodes inside workflows. Voiceflow is conversation-first and Zapier Agents runs one agent per task, so multi-agent orchestration is not their shape.

### How much does it cost to build an AI agent?

All four have free tiers. Paid entry runs from around $19 a month (Relevance AI) to around $60 to $89 a month (Voiceflow, Botpress), with AI credit limits that matter more than the sticker price. Check the sourced numbers above, they move quarterly.


## Sources

- https://www.voiceflow.com/pricing — checked 2026-09-20, confidence: unconfirmed
- https://www.voiceflow.com/ — checked 2026-09-20, confidence: unconfirmed
- https://botpress.com/pricing — checked 2026-09-20, confidence: documented
- https://botpress.com/ — checked 2026-09-20, confidence: unconfirmed
- https://relevanceai.com/pricing — checked 2026-09-20, confidence: unconfirmed
- https://relevanceai.com/ — checked 2026-09-20, confidence: unconfirmed
- https://zapier.com/agents — checked 2026-09-20, confidence: unconfirmed
- https://zapier.com/agents — checked 2026-09-20, confidence: documented
- https://zapier.com/affiliates — checked 2026-09-20, confidence: unconfirmed