Comparison
Four ways to give an AI agent a phone. Vapi, Retell and Bland are mature, full-featured voice-agent platforms. VoiceGate is deliberately narrower: a clean voice gateway for agents that already have a brain, with crypto-native billing and an agent-trust layer the others don't have.
This page is written to be fair. Where a rival matches or beats VoiceGate, it says so. If you need a full agent-building platform with dashboards and flow builders, one of the others may fit you better. If you need a thin, model-agnostic voice line that settles in stablecoin and checks agent identity, that's VoiceGate.
| VoiceGate | Vapi | Retell AI | Bland AI | |
|---|---|---|---|---|
| What it is | Voice gatewayEars, mouth and phone line for an agent that already has a brain | Agent platformFull build stack: orchestration, dashboard, integrations | Agent platformVoice-agent builder with dashboard and analytics | Agent platformAll-in-one, bundled model stack |
| Bring your own model (LLM) | YesAny LLM or agent framework via a webhook | YesBring your own LLM, TTS and telephony keys | YesChoose LLM and TTS; telephony bundled | NoLocked to Bland's own model stack |
| Pricing | From $0.06/minMargin over the carrier rate; STT + TTS included | ~$0.05/min platformUnbundled; ~$0.13–0.30/min all-in with providers | ~$0.07/min platform~$0.11–0.25/min all-in with providers | $0.07–0.12/minAll-inclusive on enterprise plans |
| Payment | USDC on BasePrepaid stablecoin, no card, no subscription | Card / subscriptionUsage billing on file | Card / subscriptionUsage billing on file | Card / plansEnterprise contracts |
| Agent identity & reputation (KYA · ERC-8004) |
YesVerified identity + portable reputation gate the line | No | No | No |
| Agent login by Verifiable Credential | YesAgent authenticates with a W3C VC (Ed25519 challenge–response) | No | No | No |
| Languages & voice | Multi-languageEN / ES / FR / DE / 中文 · male or female per call | Multi-languageWide provider choice | Multi-languageWide provider choice | Multi-languageBundled voices |
| Best fit | Autonomous agents that need a thin, crypto-native voice line with identity checks | Teams wanting maximum control and component-level tuning | Teams wanting a balance of control and simpler billing | Teams wanting the simplest all-in-one setup |
Competitor figures are indicative platform + all-in ranges reported by third-party 2026 comparisons; check each vendor's current pricing before you commit. VoiceGate margin is $0.06/min over the destination carrier rate.
Sources for competitor pricing and model support: third-party 2026 comparisons including retellai.com, superdupr.com, whitespacesolutions.ai, techsy.io and medium.com. VoiceGate does not claim affiliation with Vapi, Retell AI or Bland AI; all names are trademarks of their respective owners and are used here for comparison only.
FAQ
VoiceGate is a voice gateway for AI agents by CallsFlow Ltd. Through a Python or Node SDK, an autonomous agent places and receives real phone calls worldwide, brings its own LLM and voice, proves its identity with a verifiable credential (KYA, aligned with ERC-8004), and pays per call in USDC over the x402 standard. The open-source SDK and KYA trust layer are live; the hosted call API is in private beta from $0.06/min.
VoiceGate. Agents settle usage themselves — pay-per-call in USDC on Base via the x402 payment standard, with no card and no human in the billing loop. Platforms like Vapi, Retell AI and Bland AI bill a human-owned account on file instead.
Yes. With VoiceGate an agent calls a real PSTN phone number worldwide from code: install the SDK (pip install voicegate or npm i voicegate), authenticate the agent with its verifiable credential, and place the call. The agent keeps its own brain — VoiceGate provides the ears, mouth and phone line.
Vapi, Retell and Bland are mature, full-featured platforms for teams building voice agents with dashboards and flow builders. VoiceGate is a deliberately thin, model-agnostic voice line for autonomous agents that already have a brain, and it is the only one of the four with crypto-native pay-per-call billing (USDC/x402) and a verifiable agent-identity layer (KYA/ERC-8004). Choose a full platform for a managed build; choose VoiceGate for an agent-native gateway that settles in stablecoin and checks who is calling.
VoiceGate uses KYA (Know Your Agent): the agent logs in with a W3C Verifiable Credential via an Ed25519 challenge–response, and carries a portable on-chain identity and reputation aligned with the ERC-8004 standard, so the other side can trust which agent is calling.
The VoiceGate SDK is open source (MIT) and free — pip install voicegate or npm i voicegate, source at github.com/CallsFlow/voicegate-sdk. The KYA trust layer is live today. The hosted call API is in private beta, priced from $0.06/min.