How I learned to stop worrying and use the PSTN

The benefits of using PSTN (Public Switched Telephone Network) over VoIP (Voice over Internet Protocol) include lower costs, elastic scalability, and call quality that is as-good-or-better-than plain old telephone service. However, in unmanaged networks, such as those experienced by customers working from home or in coffee shops, visibility into network performance and ability to make changes are limited. Twilio's analysis of hundreds of billions of calls over ten years indicates that network transport issues are the number one contributor to reports of audio quality degradation for VoIP calls. To mitigate this, Twilio provides a preflight test API for workflows where VoIP calls originate in the browser, allowing developers to dip their toes into the network before placing or answering a call. The preflight test checks for jitter, latency, and packet loss, and returns a MOS (Mean Opinion Score) score between 1-5, which can be used to decide whether to proceed with VoIP or fall back to PSTN. Mobile SDKs also provide APIs to check the type of network the user is on and signal strength, allowing developers to make informed decisions about when to use VoIP or PSTN. However, these tests are sample in time and may shift, and it's essential to gather subjective feedback from users to fine-tune decision-making processes.