1. Retell AI
Best for: Teams that want both a developer API and a visual builder, with pay-as-you-go pricing
Retell lists comprehensive APIs and SDKs for programmatic control next to a drag-and-drop canvas for building call flows visually, so developers and non-developers can work on the same agents. It also lists outbound batch calling: upload an audience, schedule campaigns, and control pacing and retries. For a developer leaving Vapi, the question is mostly how each platform itemises cost.
Strengths
- APIs and SDKs plus a visual builder on one platform
- Outbound batch calling with scheduling, pacing and retries, per its site
- Lists integrations with Make, Twilio, Vonage and HubSpot
- Lists HIPAA, SOC 2 Type II, GDPR and ISO 27001 on its site
Limits
- Per-minute billing: voice infrastructure, text-to-speech, LLM and telephony are itemised, and LLM examples on its pricing page run from $0.0016 to $0.32 per minute or more depending on model
- Concurrency beyond the 20 included calls is charged at $8.00 per concurrency per month
Pricing: Pay-as-you-go from $0.07 to $0.31 per minute for AI voice agents, $10 in free credits and 20 free concurrent calls. Enterprise is custom.
Source: Retell AI's pricing page and homepage, reviewed October 2026.
2. ElevenLabs (ElevenAgents)
Best for: Teams that want a hosted agent builder with native Twilio support and a monthly plan with included minutes
ElevenLabs, whose agent product is branded ElevenAgents on its current pages, offers an interface to configure voice, language, knowledge base, system prompt and workflows, along with native SDKs for web and mobile plus WebSocket and REST APIs. Its site lists Twilio as a native connector and outbound use cases such as qualifying leads. Compared with Vapi, you work inside one vendor's voice stack instead of mixing providers.
Strengths
- Builder interface and APIs and SDKs on the same platform
- Says agents speak 70+ languages and can switch mid-conversation
- Lists SOC 2 Type II, ISO 27001 and PCI DSS Level 1; HIPAA and GDPR available for enterprise deployments
Limits
- LLM usage is billed on top of the plan, based on the model you choose
- Extra call minutes cost $0.080 each; exceeding concurrency is charged at a $0.160 per minute burst rate
- Concurrency is capped by plan, from 4 to 40 concurrent calls
Pricing: Free ($0, 15 minutes), Starter $6, Creator $22 (first month $11), Pro $99, Scale $299 and Business $990 per month, with 75 to 12,375 included minutes on the paid plans. Enterprise is custom.
Source: ElevenLabs pricing page for agents, reviewed October 2026.
3. Bland AI
Best for: Enterprises that want one per-minute rate that bundles speech and the language model
Bland positions itself as an enterprise voice AI platform for inbound and outbound calls and mentions developer access and integrations with Twilio, Salesforce, HubSpot and Slack. Unlike Vapi, its per-minute rate covers the language model, transcription and voices with no token charges, so there are fewer line items to add up. Its site also lists self-hosted and on-premises deployment.
Strengths
- One per-minute rate covers LLM, speech-to-text and text-to-speech
- Published plans, including a Start plan with no platform fee
- Lists SOC 2 Type II, HIPAA and PCI DSS v4.0 on its site
- Self-hosted and on-premises options, per its site
Limits
- Per-minute billing with transfer time billed at its own, lower rate
- Start plan caps at 100 calls per day and 10 concurrent calls; Build caps at 2,000 calls per day and 50 concurrent
- Speech and model are bundled into the rate rather than chosen provider by provider
Pricing: Start: $0.14 per minute talk time and $0.05 per minute transfer time, no platform fee. Build: $0.12 and $0.04 per minute plus $299 per month. Enterprise is custom.
Source: Bland AI's pricing page and homepage, reviewed October 2026.
4. Synthflow
Best for: Non-developers at larger organisations who want a visual builder and managed implementation
Synthflow describes a visual Flow Designer to define every step, connect APIs and create agents without development expertise, and says it connects to 200+ integrations across CRMs, contact-center platforms, calendars and data tools. It lists inbound and outbound flows, appointment booking, voicemail detection and SMS follow-ups. For teams leaving Vapi because they want less code, it is the most builder-centred option here, and the pricing page we reviewed lists an enterprise package.
Strengths
- Visual Flow Designer aimed at teams without developers
- Lists 200+ integrations including Salesforce and HubSpot
- Implementation, onboarding, training and launch support included in the enterprise package
- Lists SOC 2, HIPAA, PCI DSS, GDPR and ISO 27001 on its site
Limits
- The pricing page we reviewed lists only enterprise contracts, starting at $30,000 annually
- No published per-minute rate on that page, so cost depends on a quote
Pricing: Enterprise contracts start at $30,000 annually, priced on call volume, concurrency, telephony setup, integrations, security needs and launch support.
Source: Synthflow's pricing page and homepage, reviewed October 2026.
5. LiveKit Agents
Best for: Developers who want an open-source framework they can modify and self-host
LiveKit describes Agents as an open source framework and cloud platform for voice, video and physical AI agents. Its docs say the framework and the whole LiveKit ecosystem are open source under the Apache 2.0 license, that agents are written with Python or Node.js SDKs, and that there is full support for telephony, covering inbound and outbound calls through SIP. This is the developer-first route for teams who find a hosted platform too restrictive.
Strengths
- Open source under Apache 2.0, per its docs
- Python and Node.js SDKs
- Telephony support for inbound and outbound calls over SIP, per its docs
Limits
- You write and maintain the code, including dialing logic, retries and call logging
- LiveKit Cloud is the hosted option; see LiveKit's pricing page for its costs
Pricing: The framework is open source and free to run yourself. LiveKit Cloud is the hosted option: see LiveKit's own pricing page.
Source: LiveKit Agents docs, reviewed October 2026.
6. Pipecat
Best for: Python developers who want to assemble their own speech, language-model and voice pipeline
Pipecat describes itself as an open source Python framework for building real-time voice and multimodal conversational agents, released under the BSD-2-Clause license. Its docs describe client SDKs for JavaScript, React, React Native, iOS, Android and C++, and its repository lists telephony integrations including Twilio, Vonage, Telnyx, Plivo, Exotel and Genesys. You can self-host or use Pipecat Cloud, which its docs describe as hosted infrastructure in Daily-hosted regions or in your own VPC.
Strengths
- Open source under BSD-2-Clause; its docs say it works with 150+ AI services
- Choice of self-hosting or Pipecat Cloud
- Telephony integrations for several providers, per its repository
Limits
- A code framework, not a finished dialer: campaigns, lead lists and reporting are yours to build
- You pay for each service you choose and run the infrastructure yourself if you self-host
Pricing: Free to use under the BSD-2 license; its docs say you pay only for the services you choose. Pipecat Cloud is the managed hosting option.
Source: Pipecat documentation, reviewed October 2026.
7. VoiceOI(our product)
Best for: Outbound call floors, especially VICIdial shops, that want per-bot pricing and fronter bots that hand qualified calls to a human closer
VoiceOI is not a developer platform. It is a finished outbound system: a fronter bot calls a lead, asks your screening questions and, when the lead qualifies, hands the live call to a human closer over SIP with AI-written notes. In VICIdial, bots appear as remote agents and write outcomes back; without VICIdial, a built-in dialer runs bot campaigns with lead lists, carriers, pacing and timezone windows. Managers write scripts in a no-code builder, as recorded-voice branching bots or LLM-driven agents, and test them in a simulator. If you need custom code, use one of the frameworks above.
Strengths
- Prepaid per bot, not per minute: list prices $25 to $155 per bot per month by bot type and connection, from $25 for a fronter, with volume discounts up to 60%
- Runs inside VICIdial as remote agents, or over any SIP carrier, including Twilio and Telnyx SIP trunks
- Answering-machine detection ends the call and logs it as AM
- Google Sheets export on the Pro lead-generation tiers
- Compliance controls: do-not-call phrase handling ends the call, optional TCPA AI-voice disclosure, timezone windows, recordings and transcripts
Limits
- No public API or SDK, so it cannot replace Vapi for custom-coded agents; CRM integrations are coming soon
- Outbound only, English-first, with no SMS, calendar booking or voicemail drop, and no published HIPAA, SOC 2 or GDPR certifications
- Lead-generation (generative AI) tiers do not live-transfer; fronter and closer bots do
Pricing: $25 to $155 per bot per month at list price, billed prepaid per bot with no per-minute AI fee. Worked example: 10 bots on SIP Simple Fronter at $45 list is $450 per month, or $382.50 with the 15% discount that applies at 10 or more bots. Your carrier bills its own call minutes. See the pricing page for each tier.
Source: VoiceOI pricing, reviewed October 2026.