CallingBox
Configure an agent, dispatch a call, get structured JSON back
The Panel's Take
CallingBox is a YC-backed API that makes AI phone calls a one-liner. You configure a reusable agent with instructions, persona, and tools — then dispatch outbound or inbound calls via a single endpoint. The AI conducts the full conversation, then returns structured JSON matching whatever schema you defined. No managing telephony stacks, STT, TTS, or LLM pipelines separately. At $0.05 per connected minute all-inclusive — covering telephony, speech-to-text, language model, text-to-speech, and data extraction — it's substantially cheaper than stitching together LiveKit, Deepgram, GPT-4o, and ElevenLabs yourself (which their own benchmarks put at ~3x the cost). Sub-500ms latency with a 4.31 MOS quality score makes it production-ready. IVR navigation, voicemail detection, DTMF support, and MCP server integration cover the tricky edge cases that kill most voice implementations. Founded by Jonathan Chávez and Sebastian Crossa, the company offers $5 in free credits to get started. The use cases are obvious and immediate: appointment reminders, collections, customer support, multilingual outreach. For any team that's been putting off voice because of infrastructure complexity, CallingBox removes the excuse.
Share this verdict
CallingBox verdict: SHIP 🚀 3 ships · 1 skip from the expert panel Full review: shiporskip.io/tool/callingbox-yc-ai-phone-calling-api-json-structured-2026
Weekly AI Tool Verdicts
Get the next verdict in your inbox
7 critics review a new AI tool every day. Weekly digest — free.
Compare CallingBox with Others
Embed this verdict
Tool makers can add a live ShipOrSkip badge to their site. Badge loads track impressions; clicks route back to this review.
<a href="https://shiporskip.io/api/badge-click/callingbox-yc-ai-phone-calling-api-json-structured-2026" target="_blank" rel="noopener"><img src="https://shiporskip.io/api/badge/callingbox-yc-ai-phone-calling-api-json-structured-2026" alt="CallingBox Ship verdict on ShipOrSkip" width="360" height="90" /></a>[](https://shiporskip.io/api/badge-click/callingbox-yc-ai-phone-calling-api-json-structured-2026)<iframe src="https://shiporskip.io/embed/callingbox-yc-ai-phone-calling-api-json-structured-2026" title="CallingBox ShipOrSkip verdict" width="360" height="260" style="border:0;border-radius:16px;max-width:100%;" loading="lazy"></iframe>The reviews
“The single-endpoint design is exactly right — one call in, structured JSON out. MCP server integration means you can wire it to your existing agent tools without rebuilding. At $0.05/min I'd be crazy not to at least prototype with this.”
“This space is already crowded with Bland AI, Retell AI, and Vapi — all of which have more mature ecosystems and enterprise track records. Vapi in particular has a similar price point and years of production deployments. CallingBox needs a clearer differentiator beyond 'one endpoint.'”
“Voice is still the dominant communication channel for most of the world — banks, healthcare, governments. An API that commoditizes AI phone calls at $0.05/min will unlock workflows that no chat interface ever could. The 113-language potential alone is massive.”
“The structured JSON return is the killer feature from a product design perspective — it means you can embed AI calls in any workflow and get back data you can actually use. Podcasters, researchers, and community managers should all be paying attention.”