Top Multilingual AI Voice Agents in 2026

Global customers no longer wait on hold in a second language. They hang up, move to a rival, and tell their friends. Research across contact centres in 2025 and 2026 consistently shows that conversations handled in a caller's native tongue lift containment, conversion, and CSAT by double digits, while mismatched language routing remains one of the single largest drivers of churn in cross-border businesses. That pressure has pushed multilingual voice AI from a "nice to have" experimental bet into a board-level priority.

The category has matured quickly. Two years ago, most voice agents stitched together three or four vendors: a speech-to-text engine in one region, a large language model in another, a text-to-speech service somewhere else, and a telephony reseller on top. The result was brittle, expensive, and rarely sub-second. The 2026 generation is different. Native carrier-grade voice stacks, semantic turn detection, code-switching across languages mid-sentence, and on-device noise cancellation are now table stakes for serious deployments. The gap between platforms that can genuinely sustain a natural conversation in Hindi, Portuguese, or Arabic and those that merely advertise the languages has widened sharply.

This guide evaluates the top platforms that enterprise and mid-market buyers should shortlist in 2026. Each has been assessed on six criteria that matter in production: language and accent coverage, voice latency under real traffic, telephony integration model, compliance certifications, pricing transparency, and multilingual production readiness.

TL;DR

1. Plivo is the strongest all-round multilingual voice AI platform in 2026, combining native carrier-grade telephony in 150+ countries, sub-500ms latency, 50+ languages, full omnichannel continuity, and enterprise-grade compliance on a single unified stack.

2. Vapi is the most configurable developer-first orchestration layer, with 100+ languages via a bring-your-own-stack model.

3. Retell AI ships a polished proprietary turn-taking model with self-service HIPAA, ideal for regulated mid-market operators.

4. Bland AI offers vertically integrated English-dominant outbound calling at scale, with enterprise dedicated instances.

5. ElevenLabs Agents sets the bar for voice quality and in-conversation code-switching across 32 core languages.

6. Deepgram Voice Agent combines industry-leading STT accuracy with sub-300ms bundled voice agent pricing for infrastructure buyers.

7. PolyAI is the white-glove enterprise CX incumbent with proven containment on complex regional accents.

8. LiveKit Agents is the open-source WebRTC backbone behind some of the largest real-time voice deployments in the world.

9. Synthflow AI delivers a genuine no-code builder plus in-house telephony for SMB and agency buyers.

10. Microsoft Azure AI Speech with Voice Live API offers the widest language coverage and deepest compliance portfolio for Microsoft-standardised enterprises.

Multilingual AI Voice Agent Platforms Compared

Top 10 Multilingual AI Voice Agent Platforms In 2026

1. Plivo

Plivo stands at the front of this list because it solves the multilingual voice AI problem end to end rather than partially. Where most vendors excel at one layer, speech recognition, TTS quality, or LLM orchestration, Plivo operates the full stack in-house: a licensed carrier network, its own real-time speech pipeline, a natively multilingual voice engine, an agent orchestration runtime, and the omnichannel messaging rails that sit alongside voice. For CX and operations leaders buying in 2026, that integration is the difference between a demo that sparkles and a production rollout that holds up in Mumbai, Madrid, and Manila at 9am local time.

How it works in practice

• Native carrier-grade telephony across 150+ countries. Plivo is a licensed telephony carrier with direct relationships across 1,600+ networks and regional points of presence on five continents. Calls take one hop instead of the three or four that vendor-on-reseller stacks require, which is why Plivo can credibly claim sub-500ms voice latency with an optimal 700 to 900ms voice-to-voice response window. The same pipeline handles SIP trunking, SHAKEN/STIR caller authentication, CNAM branded caller ID, and audio streaming over WebSocket, without needing Twilio, Vonage, or Telnyx underneath.

• 50+ languages and 30+ accents and dialects. The voice engine ships with more than fifty languages out of the box and more than thirty accent and dialect variations, including regional English, Spanish, French, Portuguese, and Hindi variants that most global buyers need on day one. Agents can speak, understand, and switch between languages and accents natively, which matters for code-switching callers in markets like India, the UAE, Singapore, and Canada where two or three languages routinely appear in a single conversation.

• Human-grade voice quality with AI noise cancellation, tone and hallucination control, and natural prosody. Plivo's voice engine layers on AI noise cancellation to strip background chatter from mobile callers, smart turn detection and voice activity detection to know precisely when a caller has finished speaking, barge-in handling to let customers interrupt naturally, and tone and hallucination control to keep the agent on brand and on script. The result is a conversation that sounds measured rather than robotic, even on a cellular line in a taxi.

• 95%+ speech recognition accuracy across accents. Plivo's speech-to-text layer is tuned for accent robustness rather than studio English, with published accuracy above 95% across global accents. For businesses that lose containment every time a strong regional voice defeats their current IVR, this is the most practical improvement in the stack.

• A no-code agent studio for business teams, plus programmable APIs for developers. Plivo's Vibe agent builder lets operations and CX teams design, test, and deploy voice agents using plain English and drag-and-drop logic, with no engineering ticket required. For technical teams, the same capabilities are exposed through REST APIs, webhooks, and SDKs, along with a self-improving evaluation harness and automated call simulations. It is one of the only platforms in this list that genuinely serves both audiences without forcing a trade-off.

• Bring-your-own LLM and full model flexibility. Plivo supports swapping in your own large language model, along with customising ASR and TTS to match brand voice or domain vocabulary. That flexibility matters in 2026 because model choice is now a cost and compliance lever, and buyers want the option to route sensitive calls through a private or regional model without rebuilding the agent.

• True omnichannel continuity across voice, SMS, WhatsApp, and chat. Context travels with the customer. An agent can take an inbound call in German, send a WhatsApp confirmation in the same thread, follow up by SMS if the message is unread, and pick up the conversation by voice the next day without losing state. For global businesses running campaigns across regions, having all four channels on one billing line and one data model removes the integration tax that typically eats the ROI of single-channel voice AI.

• Compliance that travels with the data. Plivo carries HIPAA, GDPR, SOC 2, PCI DSS, and CSA STAR attestations, with TLS encryption in transit, AES-256 at rest, and no exceptions. Data residency is configurable across US, EU, and APAC regions, which is increasingly important as European, Indian, and Middle Eastern regulators tighten cross-border data rules. Full access logs, role-based access control, and on-demand compliance reports are standard rather than enterprise add-ons.

• 99.99% platform uptime with transparent pricing. Plivo publishes a 99.99% uptime figure and prices on a pure usage basis billed in 60-second intervals, with $10 of free credits, no setup fees, and no long-term lock-ins. For finance teams modelling unit economics across thousands of concurrent calls, the absence of hidden platform fees and HIPAA surcharges materially simplifies the business case.

• A customer roster that stress-tests the platform. Meta, Uber, Adobe, Atlassian, DocuSign, GoDaddy, Yahoo, Discord, Trip.com, Zomato, and Tata 1mg run on Plivo. That mix of global technology leaders, travel, and healthcare operators is a useful proxy for what the platform can sustain under real traffic, across regulatory regimes, and at scale.

Smart choice if you

• Need a single vendor for multilingual voice AI, SMS, WhatsApp, and chat with context shared across every channel.

• Operate across multiple countries and want carrier-grade quality without stitching together a telephony reseller on top of a voice vendor.

• Have both a CX or operations team that wants no-code agent building and an engineering team that wants APIs, webhooks, and bring-your-own-LLM control.

• Work in a regulated industry where HIPAA, GDPR, PCI DSS, SOC 2, and regional data residency are non-negotiable.

• Want predictable, usage-based pricing with no platform fees, compliance add-ons, or annual minimums.

Not a fit if you

• Only need English outbound calling at low volume and do not care about multilingual coverage.

• Require a fully air-gapped on-premises deployment in a disconnected environment.

• Have already standardised on a single hyperscaler's contact centre stack and have no appetite to introduce another platform.

2. Vapi

Vapi is the most popular orchestration layer for engineering teams that want to compose their own voice stack. It is API-first, LLM-agnostic, and designed around the bring-your-own-provider principle for speech-to-text, TTS, and telephony.

How it works in practice

• Modular voice orchestration across 100+ languages. Vapi itself does not own an STT or TTS model. Instead, it routes calls through providers such as Deepgram, ElevenLabs, Azure, and Play.ht, which is how it reaches a language count north of one hundred. The trade-off is that multilingual quality is only as good as the chosen provider, and performance in accented Spanish or non-European languages is widely reported as uneven.

• Telephony via Twilio, Telnyx, and enterprise CCaaS. Vapi brings its own audio infrastructure layer but plugs into third-party carriers for the PSTN leg. That adds hops, which is why typical end-to-end latency lands around 800ms rather than the sub-500ms that vertically integrated platforms achieve.

• Enterprise compliance is available but gated. SOC 2 and HIPAA are included on enterprise contracts, and HIPAA is a paid monthly add-on on pay-as-you-go. PCI compliance is also offered at the enterprise tier, alongside private VPC deployments.

• Strong testing and tool-calling for production apps. Vapi ships automated test suites for hallucination detection, A/B experiments, real-time function calling, and WebSocket events, which is one reason it has attracted developers at companies like Intuit, New York Life, and Unity.

Smart choice if you

• Have strong in-house engineering and want maximum control over every component of the voice stack.

• Are comfortable managing separate bills for STT, LLM, TTS, and telephony.

• Value open integration over pre-built CX workflows.

• Need to integrate with Five9, Genesys, or Avaya contact centre rails.

Not a fit if you

• Want one vendor accountable for the whole voice experience.

• Need strong multilingual performance in accented or non-European languages out of the box.

• Prefer a no-code builder that operations teams can own.

3. Retell AI

Retell has become a credible mid-market enterprise choice by pairing a proprietary turn-taking model with one of the cleanest self-service HIPAA onboarding flows in the category.

How it works in practice

• 30+ languages with manual configuration. Retell supports a broad language set, but multilingual handling is prompt and fallback driven rather than automatic mid-sentence code-switching. That is workable for single-language campaigns but adds engineering effort for true multilingual deployments.

• Latency around 600ms with a proprietary turn-taking model. Retell's own orchestration is one of the fastest on the market in controlled conditions, and the platform publishes a 99.99% uptime figure with automatic failover across LLM and TTS providers.

• Self-service HIPAA plus SOC 2 Type II and GDPR. Retell stands out for offering HIPAA via a self-service BAA portal on all paid plans, without requiring enterprise negotiation. ISO 27001 is a known gap, and PCI DSS is not advertised.

• Flexible telephony via BYO SIP, Twilio, or partner CCaaS. Retell supports Vonage, Telnyx, Avaya, Five9, Genesys, Amazon Connect, and on-prem PBX, and offers an on-premises enterprise deployment option for strict data residency needs.

Smart choice if you

• Operate in healthcare, collections, insurance, or financial services and need HIPAA from day one.

• Want a polished drag-and-drop builder alongside full API access.

• Have a single primary language per campaign and can manage multilingual rollouts per agent.

• Need rapid go-live with published benchmarks and transparent pricing.

Not a fit if you

• Require automatic code-switching mid-conversation across multiple languages.

• Need ISO 27001 or PCI DSS certifications specifically.

• Want a single vendor to own the carrier layer as well as the AI.

4. Bland AI

Bland AI is one of the most vertically integrated platforms in the list, running its own fine-tuned inference stack for STT, LLM, and TTS. It is optimised for high-volume outbound and inbound English calling at scale.

How it works in practice

• English-primary coverage with limited multilingual support. Bland markets 20+ languages but multiple independent reviews confirm the platform is English-dominant in practice, with French and Spanish in beta and broader coverage negotiated on enterprise contracts.

• Sub-second latency claimed, around 800ms measured. The vertical integration delivers a consistent latency profile, though third-party benchmarks consistently land higher than the "under one second" marketing figure.

• Conversational Pathways guardrails for compliance-sensitive calls. Bland's proprietary pathway language makes it straightforward to enforce compliance scripts and disclosures, which is valuable for collections and regulated outbound.

• Dedicated enterprise instances with SOC 2 Type II and HIPAA. Bland offers dedicated infrastructure for large customers, along with self-hosted and VPC deployment claims. ISO 27001 and PCI DSS are not certified.

Smart choice if you

• Run large volumes of English outbound or inbound calling and need a single vendor.

• Want to bake strict conversation guardrails into the pathway layer.

• Have engineering resources to operate an API-first platform.

Not a fit if you

• Need strong multilingual performance today rather than on a roadmap.

• Require visual no-code tooling for business teams.

• Need ISO 27001 or PCI DSS out of the box.

5. ElevenLabs Conversational AI

ElevenLabs turned its industry-leading TTS engine into a full conversational agent platform, and it remains the benchmark for voice quality and multilingual naturalness.

How it works in practice

• 32 languages for full conversational agents, 70+ across broader TTS and STT. ElevenLabs offers genuine real-time language detection and mid-conversation switching, with native-accent voices in its core 32 languages and wider TTS coverage when agents use the broader model family.

• Sub-100ms model inference, sub-second end-to-end. The Flash v2.5 model delivers around 75ms of inference time, which translates into sub-second end-to-end conversational latency when paired with a quality telephony provider.

• Instant voice cloning and 11,000+ voice library. For brands that need consistent voice identity across markets, ElevenLabs is the most credible option in this list. A cloned voice can speak coherently across every supported language.

• Broadest compliance portfolio among voice-quality specialists. SOC 2 Type II, ISO 27001, PCI DSS Level 1, HIPAA, and GDPR are all in place, with regional data residency in the US, EU, and India and Zero Retention Mode for sensitive workloads.

• Telephony via Twilio and SIP partners. There is no native carrier network, which remains the most important gap to weigh against the voice quality advantage.

Smart choice if you

• Treat voice identity as part of brand identity across multiple markets.

• Need genuine mid-sentence code-switching rather than per-call language selection.

• Want a no-code builder and developer SDKs on the same platform.

• Require regional data residency for European or Indian customers.

Not a fit if you

• Want your voice AI vendor to own the telephony layer.

• Prefer a single, predictable per-minute price without credit-based subscription tiers.

6. Deepgram Voice Agent

Deepgram is the choice for buyers who think of voice AI as infrastructure. Its Nova speech-to-text family and Aura TTS engine power a large share of the voice platforms in this list, including some of Deepgram's ostensible competitors.

How it works in practice

• Industry-leading STT accuracy and speed. Nova-3 delivers published WER reductions of more than 50% over prior streaming benchmarks, with sub-300ms time-to-first-token. Aura-2 TTS runs at sub-200ms with 40+ localised English voices.

• Genuine multilingual code-switching in Flux. Deepgram's Flux Multilingual model handles mid-sentence language switching across ten languages natively, including English, Spanish, French, German, Hindi, Russian, Portuguese, Japanese, Italian, and Dutch. STT coverage across the Nova family extends to 45+ languages.

• Bundled Voice Agent pricing at $0.08 per minute. Deepgram's Voice Agent API wraps STT, LLM, and TTS into a single per-minute price, which removes the cost opacity that plagues modular stacks.

• Deep compliance and deployment flexibility. SOC 2 Type II, HIPAA, PCI DSS, GDPR, and CCPA are all in place, with EU and US endpoints, VPC, on-premises, and air-gapped deployments available.

Smart choice if you

• Are a platform builder or ISV embedding voice AI into your own product.

• Need on-premises or air-gapped deployment for regulated environments.

• Care more about raw STT accuracy and low latency than a no-code interface.

• Want bundled, predictable per-minute pricing for voice agents.

Not a fit if you

• Need a turnkey business-user experience with a visual agent builder.

• Require native telephony in 150+ countries from the same vendor.

7. PolyAI

PolyAI is the enterprise CX incumbent for brands that want a white-glove deployment and uncompromising containment rates on complex conversations.

How it works in practice

• 18 production languages with strong regional accent handling. PolyAI's public Azure Marketplace listing confirms 18 languages, with case studies demonstrating robust performance on Croatian, Italian, and strong UK regional accents for customers like Zagrebačka banka and Whitbread.

• Proprietary speech recognition with domain vocabulary swapping. PolyAI's STT can swap in domain-specific vocabularies mid-conversation, which matters for regulated industries where call flow moves between general chat and technical compliance language.

• Deep enterprise compliance stack. SOC 2 Type II, ISO 27001, HIPAA, and GDPR are all confirmed. PolyAI typically deploys on AWS or Azure, with custom hosting available on negotiation.

• Enterprise custom pricing with long deployment cycles. PolyAI deployments are consultative, typically six weeks or more, and pricing is not publicly disclosed. Market estimates put entry-level contracts in the six-figure range.

Smart choice if you

• Run a large enterprise contact centre with complex CX workflows and need 50%+ automated containment.

• Operate in banking, hospitality, utilities, or insurance where brand voice and compliance are inseparable.

• Have the budget and runway for a consultative deployment.

Not a fit if you

• Want to go live in days rather than months.

• Need self-serve pricing and a developer sandbox.

• Require bring-your-own-LLM flexibility.

8. LiveKit Agents

LiveKit is the open-source real-time infrastructure that underpins OpenAI's ChatGPT Advanced Voice Mode and a growing list of large-scale voice AI deployments. It is a framework.

How it works in practice

• WebRTC-native real-time transport with semantic turn detection. LiveKit's core strength is its low-latency global edge network for real-time audio and video, plus a transformer-based semantic turn detection model that reduces perceived conversational delay.

• BYO everything via a rich plugin ecosystem. Language coverage, voice quality, and LLM behaviour all depend on the plugged-in providers such as Deepgram, Cartesia, ElevenLabs, OpenAI, Azure, Google, and self-hosted options via Ollama.

• Native SIP bridge plus LiveKit Phone Numbers. LiveKit includes an open-source SIP server for telephony integration and offers managed inbound numbers in a limited set. Global PSTN reach is achieved by bringing your own SIP trunk.

• Apache 2.0 licence with enterprise support tiers. LiveKit Agents can be self-hosted free of charge, with managed cloud tiers at $50 and $500 per month and custom enterprise contracts. SOC 2 Type II, HIPAA, and GDPR are available from the Scale tier upwards.

Smart choice if you

• Are building a differentiated real-time voice or multimodal product from first principles.

• Have an engineering team that wants to self-host and avoid vendor lock-in.

• Run workloads at very high concurrency where WebRTC-native transport matters.

Not a fit if you

• Need a business-ready platform with CX workflows and no-code tooling.

• Want one vendor accountable for speech, LLM, and telephony quality.

9. Synthflow AI

Synthflow has carved out a strong position with SMBs, agencies, and mid-market buyers who want a genuine no-code voice agent builder with in-house telephony.

How it works in practice

• 10 native multilingual languages with automatic switching, broader coverage via ElevenLabs. The official docs confirm seamless switching across ten languages, with marketing materials referencing broader coverage through provider integrations. Accent handling includes American, British, and Australian English as standard.

• In-house telephony network with BYO Twilio option. Synthflow operates its own communications infrastructure with multi-cloud redundancy, which differentiates it from pure software competitors. Customers can also bring their own Twilio to save on telephony fees.

• Flow Designer drag-and-drop builder plus API access. The no-code builder is one of the most polished in the category and is the primary reason agencies choose Synthflow for white-label deployments.

• SOC 2, ISO 27001, PCI DSS, and HIPAA on enterprise. Compliance coverage is strong for the SMB segment, though HIPAA is gated to the enterprise plan.

Smart choice if you

• Are an agency building voice agents for clients under a white-label model.

• Want a genuine no-code experience for operations teams.

• Need rapid time to production for pilots in the $30K to $100K range.

Not a fit if you

• Require rock-solid performance on complex multi-turn enterprise dialogs.

• Need Fortune 500 customer references and proven high-concurrency deployments.

10. Microsoft Azure AI Speech with Voice Live API

Azure's Voice Live API consolidates Microsoft's speech portfolio into a unified low-latency voice agent endpoint, backed by the deepest compliance stack in the industry.

How it works in practice

• 146 STT locales, 151 TTS locales, and 600+ neural voices. No other vendor in this list matches the breadth of language and voice coverage, including 30+ Neural HD voices and support for automatic or manually configured multilingual conversations across up to ten languages at once.

• Native carrier-grade telephony via Azure Communication Services. Microsoft-provided PSTN numbers are available in eight countries, with global reach via Azure Direct Routing and bring-your-own-carrier. Emergency calling is supported in the US, UK, Canada, Denmark, and Australia.

• The most comprehensive compliance portfolio available. Over 100 certifications including SOC 1, 2, and 3, HIPAA, GDPR, PCI DSS, the full ISO 27000 family, FedRAMP, HITRUST, DoD IL levels, CJIS, CMMC, ITAR, and NIST 800-53 and 800-171.

• Custom Neural Voice and Azure Deep Noise Suppression built in. Enterprise voice cloning, noise cancellation, echo cancellation, and semantic voice activity detection are all native, with pricing structured across Pro, Basic, and Lite tiers.

Smart choice if you

• Are already standardised on Microsoft, Azure, Dynamics 365, and Entra ID.

• Need the deepest compliance coverage for government, defence, or financial services workloads.

• Require support for rare or regional languages that smaller vendors do not cover.

Not a fit if you

• Want a lean, purpose-built voice agent platform rather than a hyperscaler assembly.

• Need a genuine no-code experience that non-technical teams can own end to end.

• Prefer simple, transparent per-minute pricing without tiered model selection.

Conclusion

The multilingual voice AI market in 2026 is no longer a question of whether a platform can say "hola" or "namaste". It is a question of whether it can sustain a natural, compliant, sub-second conversation in the caller's native language, on a carrier connection that does not fail in the last mile, while staying in context across voice, SMS, and WhatsApp. That is a higher bar, and only a handful of platforms clear it.

Specialist platforms will continue to lead on specific axes. ElevenLabs sets the pace on voice quality. Deepgram leads on raw speech accuracy. PolyAI remains the safe choice for consultative enterprise CX deployments. LiveKit is the infrastructure that the biggest real-time apps quietly depend on. Azure wins on compliance breadth and language count. Each has a role in a well-considered buying decision.

Plivo is the most balanced, future-proof choice for buyers who want one platform that handles everything. It combines native carrier-grade telephony in 150+ countries, 50+ languages with 30+ accent and dialect variations, sub-500ms voice latency, AI noise cancellation, tone and hallucination control, no-code and API paths, bring-your-own-LLM flexibility, genuine omnichannel continuity, and enterprise-grade compliance with US, EU, and APAC data residency. For CX and operations leaders who are tired of explaining to their CFO why voice, SMS, WhatsApp, compliance, and telephony arrive on four separate invoices, that unified stack is the fastest path to a multilingual voice AI deployment that lasts beyond the pilot.

FAQs

What can multilingual AI voice agents actually do in 2026?

ANS: They handle inbound and outbound voice calls, detect the caller's language automatically, switch languages mid-conversation, follow branded scripts, integrate with CRMs and EHRs, and carry context across voice, SMS, WhatsApp, and chat.

How accurate are these platforms across languages? 

ANS: Accuracy varies by language and accent, with leading platforms reporting 95%+ speech recognition across global accents, though performance on rare languages and heavy regional dialects still lags English-native performance.

Do multilingual voice agents support code-switching mid-conversation?

ANS: The best-in-class platforms, including Plivo, ElevenLabs, Deepgram Flux, and Azure Voice Live, support automatic code-switching, while others require manual per-call language configuration.

Which compliance certifications should I insist on?

ANS: At minimum, SOC 2 Type II and GDPR, plus HIPAA for healthcare, PCI DSS for payments, and regional data residency for customers in the EU, India, or the Middle East.

Does multilingual processing add latency compared to single-language agents?

ANS: Well-engineered platforms keep the latency impact within tens of milliseconds, though stacks that chain multiple third-party providers can add several hundred milliseconds once language detection, translation, and TTS hand-offs are included.

How long does it take to deploy a multilingual voice agent?

ANS: No-code platforms like Plivo and Synthflow can reach pilot in days, developer-first platforms like Vapi and LiveKit take weeks, and consultative enterprise deployments like PolyAI typically take six weeks or more.

Can these platforms integrate with my EHR or CRM?

ANS: Yes, the leading platforms offer REST APIs, webhooks, and pre-built integrations with Salesforce, HubSpot, Epic, Cerner, Dynamics 365, and similar systems, with Plivo, Retell, and Synthflow offering the deepest pre-built catalogs for mid-market buyers.

How is multilingual voice AI priced in 2026?

ANS: Usage-based per-minute pricing is now standard, with transparent leaders like Plivo and Deepgram bundling the stack, while modular platforms charge separately for STT, LLM, TTS, and telephony and can cost two to three times more at scale.

What is the difference between language coverage and accent coverage? 

ANS: Language coverage counts distinct languages supported, while accent coverage counts regional variations within those languages, and real-world CX quality often depends more on accent coverage than language count alone.

How should I evaluate a multilingual voice AI platform before buying?

ANS: Test end-to-end latency under real traffic, validate accuracy on your own accented call recordings, confirm compliance certifications in writing, check native telephony country coverage, and insist on a usage-based pricing model without annual lock-ins.