# Alternatives to Kalyvox > Source: https://theagentsindex.com/kalyvox/alternatives (current datasheets, evidence-ranked) Candidates share the baseline category or are previously researched peers. Requirements, preserved strengths, explicit trade-offs and research coverage decide the order; paid tier does not. ## Shortlist ### 1. ElevenLabs Agents Hosted platform for building voice and chat agents, with telephony, SDKs and a choice of LLM. **Research coverage:** 35/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — OpenAI models are natively supported and are the one provider family the vendor says stays fully available under EU data residency.](https://elevenlabs.io/docs/eleven-agents/customization/llm) - [Model choice: yes — You pick the model per agent, plus a backup cascade; LLM usage is billed on top of the plan and varies by model.](https://elevenlabs.io/docs/eleven-agents/customization/llm) - [Self-hosted: partial — The full agent runtime can run in your own VPC or hardware on AWS or GCP, but the documentation is NDA-gated and sold through the account team; Azure is unreleased.](https://elevenlabs.io/docs/overview/capabilities/private-deployment) **Trade-offs against Kalyvox:** - [Getting out: partial — Agents, tools and tests pull down as files via the CLI and conversations are readable over the API, but unused paid credits expire on cancel or downgrade and rollover caps at two months.](https://elevenlabs.io/pricing/agents) [View ElevenLabs Agents](https://theagentsindex.com/elevenlabs-conversational-ai) ### 2. Synthflow Enterprise voice AI platform with in-house telephony for inbound and outbound call automation. **Research coverage:** 35/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — The model selector lists GPT-4o, GPT-4.1 and multiple GPT-5 variants for agent responses.](https://docs.synthflow.ai/general-configuration) - [Model choice: partial — You pick the model per agent, but only from Synthflow's list of GPT and Synthflow LLM options.](https://docs.synthflow.ai/general-configuration) - [Free tier: yes — You can build an agent at no cost; charges begin at launch on a pay-as-you-go basis.](https://synthflow.ai/) **Trade-offs against Kalyvox:** - [Seat model: no — Pricing is scoped on call volume and concurrency, not on seats; workspace members are governed by roles instead.](https://synthflow.ai/pricing) - [Getting out: partial — Manual CSV export of call logs is available to all; scheduled exports to S3, BigQuery or SFTP are Enterprise-only, and unused minutes carry over only if the agreement says so.](https://docs.synthflow.ai/export-call-data) [View Synthflow](https://theagentsindex.com/synthflow-ai) ### 3. Vapi Developer platform for building, testing and deploying voice AI agents that make and receive phone calls. **Research coverage:** 35/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — OpenAI GPT models are selectable as the assistant's LLM.](https://docs.vapi.ai/providers/model/openai) - [Model choice: yes — You choose transcriber, LLM and voice independently and can swap any of them.](https://vapi.ai/platform) - [Self-hosted: partial — Self-serve is hosted only; on-premise is offered to large enterprises, and the orchestration layer otherwise never leaves Vapi.](https://docs.vapi.ai/faq) **Trade-offs against Kalyvox:** - [Agent permissions: partial — Tools fire mid-call without human approval; a per-tool rejection plan is the mechanism that withholds an action.](https://docs.vapi.ai/tools/tool-rejection-plan) - [Seat model: no — Nothing is priced per seat: the plan table meters call minutes and concurrent lines only, and members are invited with RBAC roles.](https://vapi.ai/pricing) [View Vapi](https://theagentsindex.com/vapi) ### 4. OmniDimension No-code platform for building voice AI agents and running them on phone, web chat, WhatsApp, email and SMS. **Research coverage:** 35/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — OpenAI models are the largest block in the published catalogue, offered both directly and through Azure, and the agent API accepts them by name.](https://omnidim.io/pricing) - [Model choice: yes — You choose the speech-to-text, LLM and text-to-speech provider per agent and may mix them freely; the vendor does not pin you to one stack.](https://omnidim.io/pricing) - [API access: yes — A documented REST API with a Bearer key covers agents, calls, campaigns, numbers and analytics, with Python, TypeScript and browser SDKs and a downloadable OpenAPI spec.](https://docs.omnidim.io/docs/api-reference) **Trade-offs against Kalyvox:** - [Agent permissions: partial — The agent acts alone inside limits you write in advance: natural-language transfer and hang-up conditions, a hard call-length ceiling and per-campaign calling hours, so escalation is pre-configured rather than requested mid-call.](https://docs.omnidim.io/docs/api-reference/agents/createAgent) - [Getting out: partial — Unused balance survives plan changes and top-ups with no published expiry, and transcripts and recordings can be pulled through the call-logs API, but deletion is a manual email request and no bulk account export is documented.](https://omnidim.io/pricing) [View OmniDimension](https://theagentsindex.com/omnidimension) ### 5. Retell AI Pay-as-you-go platform for building, testing and running AI phone, chat and SMS agents. **Research coverage:** 34/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — Multiple GPT tiers are offered as conversation models, each with its own per-minute rate and an optional faster tier for lower latency.](https://www.retellai.com/pricing) - [Model choice: yes — You pick the conversation model per agent from a published, per-minute-priced list, and you can substitute your own model entirely through the custom-LLM WebSocket.](https://docs.retellai.com/integrate-llm/overview) - [API access: yes — A documented REST API with Node.js and Python SDKs covers agents, calls, phone numbers and chats, and it is listed as included on the entry pay-as-you-go plan.](https://www.retellai.com/pricing) **Trade-offs against Kalyvox:** - [Agent permissions: partial — Prohibited-topic guardrails screen both the agent's replies and user input, and tools are explicitly wired per node, but guardrails only swap in a placeholder message rather than stopping or escalating the call.](https://docs.retellai.com/build/guardrails) - [Seat model: no — Nothing is charged per user: the published rate card meters minutes, messages and monthly items like phone numbers and concurrency, so team size does not change the bill.](https://www.retellai.com/pricing) [View Retell AI](https://theagentsindex.com/retell-ai) ### 6. TelEcho Conversational AI platform for voice and messaging agents that run customer calls and update connected systems. **Research coverage:** 31/35 criteria **Where it improves on Kalyvox:** - [GPT: yes — GPT is the platform's reasoning layer: the pricing calculator meters GPT-5, GPT-5 Mini, GPT-5 Nano, GPT 4.1 and GPT 4.1 Mini, and OpenAI is the sole LLM provider named in the sub-processor table.](https://telecho.io/security) - [Model choice: partial — You choose the telephony carrier, the STT engine, the TTS voice and the execution pipeline, but every LLM option in the calculator comes from one vendor, so model choice stops at OpenAI.](https://telecho.io/features) - [MCP server: yes — TelEcho documents a native MCP integration letting an agent inside ChatGPT or Claude define and configure TelEcho agents; no server address, tool inventory or auth flow is published to verify scope.](https://telecho.io/how-it-works) **Trade-offs against Kalyvox:** - [Seat model: no — Nothing is priced per seat: users are invited into one account and charges follow minutes, so there is no published per-user fee, no seat floor and no seat ceiling, only 'limited team access' on Build.](https://telecho.io/legal/terms) - [Getting out: partial — You keep ownership of recordings and transcripts, may request a copy of personal data and can set retention yourself, but no self-serve bulk export is documented and metrics export is an Enterprise line; billing is metered, so no prepaid credits can expire.](https://telecho.io/legal/terms) [View TelEcho](https://theagentsindex.com/telecho) ## Method Unknown data is never treated as a benefit or a trade-off. Featured placement is labelled but cannot alter recommendation order.