We ran 1 million minutes of test calls across Twilio, Telnyx, and Plivo over three months for a high-volume contact centre client. Here are the real numbers — cost, quality, latency, support, and developer experience.
Pricing Comparison (Per Minute, USA Inbound/Outbound)
| Provider | Inbound (USD/min) | Outbound (USD/min) | Phone Number | SMS (per message) |
|---|---|---|---|---|
| Twilio | $0.0085 | $0.0140 | $1.15/mo | $0.0079 |
| Telnyx | $0.0035 | $0.0080 | $1.00/mo | $0.0040 |
| Plivo | $0.0055 | $0.0085 | $0.80/mo | $0.0035 |
| SignalWire | $0.0025 | $0.0060 | $1.50/mo | $0.0075 |
At 100,000 outbound minutes/month: Twilio costs $1,400. Telnyx costs $800. Plivo costs $850. At scale, Telnyx and Plivo save 40–50% over Twilio.
Call Quality
In our testing, call quality was excellent across all three for US domestic calls. MOS scores (Mean Opinion Score — the standard voice quality metric) averaged 4.2–4.4 out of 5 for all three. International calls told a different story. Twilio has the largest carrier network and consistently delivered the best international quality, especially for India, the Middle East, and Southeast Asia. Telnyx was close for Europe and Australia. Plivo struggled with some Latin American destinations.
Latency
For AI voice agent applications, call setup latency (time from API call to first ring) matters more than in-call latency. In our benchmarks from India-based servers calling US numbers: Twilio averaged 350ms, Telnyx averaged 290ms, Plivo averaged 380ms. For real-time AI applications, Telnyx's lower latency is a meaningful advantage.
Developer Experience
| Factor | Twilio | Telnyx | Plivo |
|---|---|---|---|
| Documentation | Excellent (industry gold standard) | Good and improving | Good |
| API design | REST + TwiML (XML) | REST + TeXML (TwiML compatible) | REST + XML |
| Migration from Twilio | N/A | Very easy (TeXML is TwiML compatible) | Easy |
| Python SDK | Excellent | Good | Good |
| Webhooks | Reliable | Reliable | Reliable |
| Support | Email/chat (slow for free tier) | Dedicated support faster | Email/ticket |
Our Recommendation by Use Case
- Twilio: If you need the best international coverage and are willing to pay the premium. Also the safest choice for regulated industries (healthcare, finance) due to HIPAA BAA and SOC 2.
- Telnyx: Best value for US/Europe calling. TeXML compatibility makes migration from Twilio low-risk. Best latency in our tests.
- Plivo: Good for high-volume SMS campaigns and US/Canada calling on a tight budget.
- SignalWire: Cheapest rates for high-volume calling, but smaller ecosystem and fewer integrations.
Twilio is the safe enterprise default — premium price, premium network, gold-standard documentation. Telnyx is the smart choice for cost-sensitive high-volume applications, especially if you are already on Twilio (the TeXML migration is one afternoon of work). Plivo is a solid budget alternative for SMS-heavy use cases. Our CPaaS team has integrated all four platforms and can help you pick the right one for your traffic volume and budget.