# Callr

> Callr is the voice API your business runs on. Capture, attribute, and convert every inbound call across 220+ countries on the only API-first voice platform that owns its carrier network.

Callr is a French, API-first programmable voice & SMS platform. It runs on its own servers — not on public cloud — and lets customers choose where data is hosted: France, the United States or Singapore. France hosting keeps data outside the reach of the US CLOUD Act and FISA 702.

## Pages

- [Home](https://www.callr.com/): The voice API your business runs on.
- [Features](https://www.callr.com/resources/features/): Explore every capability behind Callr — programmable voice and SMS, conversation AI, call tracking and a carrier network we own across 220+ countries.
- [Case studies](https://www.callr.com/resources/case-studies/): See how Bien’ici, Zenchef, and Business Lead build on Callr’s voice and SMS API to capture, attribute, and convert every customer call.
- [Blog](https://www.callr.com/blog/): Practical guides, deep dives, and honest platform comparisons on programmable voice, call tracking, and conversational AI — created by the experts who build Callr.

## Blog

- [Callr vs Kaisa (Freespee) 2026: Call Tracking & Conversation Intelligence for Marketplaces](https://www.callr.com/blog/callr-vs-freespee-kaisa/): Compare Callr and Kaisa (Freespee) for marketplace call tracking and conversation intelligence: carrier-owned infrastructure vs. a wholesale-carrier software layer.
- [Callr vs iovox 2026: Call Tracking & Conversation Intelligence for Marketplaces](https://www.callr.com/blog/callr-vs-iovox/): Compare Callr and iovox for marketplace call tracking: carrier-native attribution, built-in conversation intelligence, voice AI flows, EU residency and pricing.
- [Callr vs Plivo 2026: Carrier-Native Infrastructure vs. the Aggregator Model](https://www.callr.com/blog/callr-vs-plivo/): Compare Callr and Plivo in 2026: owned EU carrier infrastructure vs. the aggregator model, voice AI options, compliance, pricing, and migration.
- [Callr vs Telnyx 2026: Two Carrier-Native Platforms, Two Philosophies](https://www.callr.com/blog/callr-vs-telnyx/): Callr vs Telnyx in 2026: both own their carrier infrastructure. Compare EU-native data residency, built-in call tracking, voice AI, and pricing models.
- [Callr vs Twilio 2026: The Carrier-Native Alternative to the Default Choice](https://www.callr.com/blog/callr-vs-twilio/): Compare Callr and Twilio for voice in 2026: owned EU carrier infrastructure, default EU data residency, voice AI, real pricing at scale, and a migration path.
- [Callr vs Vonage 2026: What the Ericsson Acquisition Means for Developers](https://www.callr.com/blog/callr-vs-vonage/): Compare Callr and Vonage in 2026: owned EU carrier infrastructure vs an Ericsson subsidiary. Architecture, voice AI, pricing, compliance and migration.
- [What Is a Voice AI Agent?](https://www.callr.com/blog/what-is-a-voice-ai-agent/): A voice AI agent answers calls, understands intent, and acts on it automatically. See what they do, how they beat IVR, and where they fit your business.
- [What Is Call Tracking?](https://www.callr.com/blog/what-is-call-tracking/): Call tracking connects inbound phone calls to your marketing, so you can see which campaigns drive calls, leads, and revenue, and act on it.
- [How Marketplaces Use Conversational Intelligence to Measure Leads](https://www.callr.com/blog/how-marketplaces-can-leverage-conversational-intelligence-data-to-measure-leads/): Learn how marketplaces use conversational intelligence to spot high-intent buyers, score leads from calls and SMS, and turn more conversations into sales.
- [The Handbook for Safe User-to-User Communications in the Sharing Economy](https://www.callr.com/blog/sharing-economy-communications/): How peer-to-peer marketplaces build trust and safety into user communications — with SMS, voice, number masking, and identity, plus advice from P2P operators.
- [How to Build Trust and Communication into a Peer-to-Peer Marketplace](https://www.callr.com/blog/improving-peer-to-peer-marketplace/): Practical advice for marketplace founders on choosing communication channels, real-time notifications, and trust mechanisms that keep buyers and sellers engaged.
- [Overcoming P2P Challenges (Part 2): Trust and Security](https://www.callr.com/blog/p2p-challenges-trust-and-security/): How peer-to-peer marketplaces build trust and security — 2FA, masked numbers, reputation systems, moderation — with practical advice from platform founders.
- [Overcoming P2P Challenges (Part 1): Choosing the Right Notification System](https://www.callr.com/blog/p2p-choosing-notification-system/): Email, in-app chat, SMS or voice? A practical guide to picking notification channels that keep your peer-to-peer marketplace fast, safe and trusted.
- [What Is an API? A Plain-English Guide](https://www.callr.com/blog/what-is-an-api/): A clear, jargon-free explanation of what an API is, how APIs and webhooks work, with everyday examples and how Callr uses both to automate workflows.
- [Turn Call Data Into Sales: A Practical Guide to Optimization](https://www.callr.com/blog/how-businesses-can-improve-sales-using-call-data-sales-optimization/): Every customer call carries data you can act on. Here's how to use call tracking and analysis to find better leads, personalize selling, and grow revenue.
- [Better Customer Experience with AI Agents, SMS, and IVR](https://www.callr.com/blog/improving-user-experience-with-chabots-sms-and-ivr/): How AI agents, SMS automation, and modern IVR work together to deliver faster, more personal customer experiences across voice and messaging.
- [SMS API & SaaS Integration: The FAQs, Answered](https://www.callr.com/blog/sms-api-saas-integration/): Thinking about adding an SMS API to your SaaS platform? Integration timelines, common pitfalls, data ownership, and A2P regulations, explained.
- [Fighting Robocalls: What ARCEP Decision 0881 Means for Telecom Professionals](https://www.callr.com/blog/robocall-telco-automation-arcep-decision-0881/): How ARCEP Decision 0881 reshaped caller ID rules and automated calling in France, and what it means for contact centers and telecom operators.
- [Bloctel Explained: The French Do-Not-Call List for Businesses and Consumers](https://www.callr.com/blog/bloctel-explained-for-businesses-and-consumers/): How Bloctel, France's official do-not-call registry, works for businesses cleaning prospecting lists and for consumers blocking unwanted calls.
- [The Why, What and How of GDPR for Telcos](https://www.callr.com/blog/the-why-what-and-how-of-gdpr-for-telcos/): A practical guide to GDPR for telecom businesses: why it exists, the rights it grants, the duties it imposes, and how to turn compliance into trust.
- [Don't Kill Telephony: Why ASR and ACD Scores Matter](https://www.callr.com/blog/dont-kill-telephony-why-good-asr-and-acd-scores-matter/): Two call-center metrics, ASR and ACD, reveal your traffic quality and keep carriers on your side. Here's how to read them and how to fix low scores.
- [The Three Paths to VoIP: SIP Trunk, SIP Registrar, and IAX](https://www.callr.com/blog/voip-sip-trunk-registrar-sip-iax/): Choosing a business VoIP setup? Compare SIP Trunk, SIP Registrar, and IAX across bandwidth, codecs, IP authentication, and NAT to pick the right fit.
- [From Numbers to Trunk Management: The Self-Serve VoIP Platform](https://www.callr.com/blog/voip-platform/): Set up SIP and IAX trunks, buy numbers in 30+ countries, and track voice usage from one self-serve VoIP platform — built on Callr's owned EU carrier network.
- [Telecom Acronym Reference: A Plain-English Glossary](https://www.callr.com/blog/telco-acronym-reference/): A clear, practical glossary of the telecom acronyms you actually meet building voice and SMS — from API, CDR and DID to SIP, RTP and VoIP.
- [Introducing the Callr Tech Blog: a closer look at our telco infrastructure](https://www.callr.com/blog/zooming-telco-infrastructure-callr-tech-blog/): We're opening up the engineering behind Callr's telco platform — and open-sourcing tools like our Kamailio exporter for Prometheus. Here's why.
- [Can SaaS Afford to Leave SMS on the Sidelines?](https://www.callr.com/blog/can-saas-afford-to-keep-sms-on-the-sidelines/): SMS quietly became the default A2P channel. Here's why SaaS teams use it for onboarding, retention, and customer service — and where it beats email and push.

## Case studies

- [How Bien’ici streamlines and monetizes property leads with Callr](https://www.callr.com/resources/case-studies/bienici/): France’s third-largest property portal brands every lead and proves its value to 12,000+ professionals with call tracking on Callr’s voice API.
- [Business Lead helps small businesses turn more calls into customers with Callr](https://www.callr.com/resources/case-studies/business-lead/): A communications provider that lets local businesses handle every inbound call and SMS — no dedicated team, no third-party call center — built on Callr’s API.
- [Zenchef proves its value to restaurants with call tracking](https://www.callr.com/resources/case-studies/zenchef/): The restaurant marketing platform uses unique tracked numbers and SMS on Callr’s API to prove — in hard numbers — the bookings it drives for 3,000+ restaurants.

## Legal

- [Legal Notices](https://www.callr.com/legal/): Publisher, hosting, intellectual property, liability, governing law.
- [Privacy Policy / GDPR](https://www.callr.com/gdpr/): Data collected, usage, your rights, data security and server locations.
- [Terms and Conditions (PDF)](https://static.callr.com/my/pdf/CALLR-Terms-and-Conditions-USD-20260301.pdf)

## Optional

- [Full site content as Markdown](https://www.callr.com/llms-full.txt)
- Localized sites — French: https://www.callr.com/fr/ · Spanish: https://www.callr.com/es/