Retell AI alternatives · AI Agents
Open-source alternatives to Retell AI
Retell AI is not described as open source on its own site. 23 of the 101 other AI agents in this directory are open source, according to their own sites.
Retell AI is a paid product with a free trial, starting at $0 to start, then $0.07 to $0.31 per minute for voice agents. 21 of them are free or have a free plan.
23 tools · Listings checked up to Nov 12, 2026 · Where the facts come from
The 12 closest to Retell AI
- Free plan · from $20/mo
Letta
Stateful agents with long-term memory, from the MemGPT team
- Letta starts at $20 per month. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Letta has a free plan. Retell AI does not, though it has a free trial.
- Letta is open source, according to its own site.
- Letta also covers workflow automation.
- Free trial · from $150/mo
E2B
Cloud sandboxes where AI agents run code and tools
- E2B starts at $150 per month, plus per-second sandbox usage. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- E2B is open source, according to its own site.
- Retell AI also covers chatbots.
- Free plan
Mem0
Memory layer that lets AI agents remember across sessions
- Mem0 has a free plan. Retell AI does not, though it has a free trial.
- Mem0 is open source and self-hostable, according to its own site.
- Retell AI also covers chatbots.
- Free plan · from $42.50/mo
AutoGPT
Open-source agent platform with a hosted team of AI Experts
- AutoGPT starts at $42.50 per month, billed yearly at $510 (Pro); $50 billed monthly. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- AutoGPT has a free plan. Retell AI does not, though it has a free trial.
- AutoGPT is open source and self-hostable, according to its own site.
- AutoGPT also covers workflow automation.
- Free plan · from $590/yr
Dify
Open-source platform for building AI agents and agentic workflows
- Dify starts at $590 per workspace / year (Professional); $59 billed monthly. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Dify has a free plan. Retell AI does not, though it has a free trial.
- Dify is open source and self-hostable, according to its own site.
- Dify also covers workflow automation and no-code.
- Free plan · from $50/mo
Kortix
Open-source platform for running AI agents from a git repo you own
- Kortix starts at $50 per month for 5,000 credits (Credits), with unlimited members. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Kortix has a free plan. Retell AI does not, though it has a free trial.
- Only Kortix lists macOS, Windows, Linux, iOS and Android apps.
- Kortix is open source and self-hostable, according to its own site.
- Free
goose
Open-source AI agent with a desktop app, CLI and API
- goose is free. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- goose has a free plan. Retell AI does not, though it has a free trial.
- Only goose lists macOS, Windows and Linux apps.
- Only Retell AI lists a web app.
- Free plan
Langflow
Open-source visual builder for AI agents and MCP servers
- Langflow has a free plan. Retell AI does not, though it has a free trial.
- Only Langflow lists macOS, Windows and Linux apps.
- Langflow is open source and self-hostable, according to its own site.
- Langflow also covers templates.
- Free plan · from $21.25/mo
Sim
Open-source workspace for building and running AI agents
- Sim starts at $21.25 per user / month, billed annually ($255); $25 billed monthly. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Sim has a free plan. Retell AI does not, though it has a free trial.
- Only Sim lists a macOS app.
- Sim is open source and self-hostable, according to its own site.
- Free plan · from $29/mo
Agenta
Open-source workspace for building team AI agents and automations
- Agenta starts at $29 per month (Pro, unlimited users, 10,000 agent runs included). Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Agenta has a free plan. Retell AI does not, though it has a free trial.
- Agenta is open source and self-hostable, according to its own site.
- Agenta also covers templates, workflow automation and no-code.
- Free plan · from $5
Browser Use
Browser agents and cloud browsers for AI apps
- Browser Use starts at $5 minimum top-up, used as you go. Retell AI starts at $0 to start, then $0.07 to $0.31 per minute for voice agents.
- Browser Use has a free plan. Retell AI does not, though it has a free trial.
- Browser Use is open source, according to its own site.
- Retell AI also covers chatbots.
- Paid
SuperAGI
AI-native sales apps and agents, from the open-source agent project
- SuperAGI is open source, according to its own site.
- SuperAGI also covers sales pipeline and workflow automation.
- Retell AI also covers chatbots.
11 more that are open source
All 23 in one tableCommon questions
Is there an open-source alternative to Retell AI?
Yes. Letta, E2B, Mem0, AutoGPT, Dify, Kortix, goose, Langflow and 15 more are open source, according to their own sites.
Is Retell AI open source?
Retell AI is not described as open source on its own site. The listing was checked on Nov 12, 2026 against the pages it cites.
Which of these AI agents are free?
Letta, Mem0, AutoGPT, Dify, Kortix, goose, Langflow, Sim and 13 more are free or have a free plan.
When was this checked?
Each listing shows its own date. On this page they run from Oct 5, 2026 to Nov 12, 2026. Vendors change prices and plans without notice, so confirm on their site before you buy.
This page is built from the listings. A tool is here because its listing says so, and the order is how close each is to Retell AI: the alternatives its listing names first, then the tools that share the most features with it.