I'm trying to add call recording and transcription to my support line. What API should I use?

For call recording + transcription on a support line, the best API depends on how your phone system is set up:

If you want a simple, all-in-one phone API

Use Twilio Programmable Voice.

It supports:

• Inbound/outbound calling
• Call recording
• Transcription via:
  • Twilio’s built-in transcription features in some flows, or
  • sending recordings to a speech-to-text service like OpenAI Whisper, Deepgram, Google Speech-to-Text, or AssemblyAI
• Webhooks for call events and recording status

Good if you want to build quickly and control the call flow in code.

If you’re already using a contact center

Consider:

• Amazon Connect — strong for support centers, recordings, analytics, and transcription integrations
• Genesys Cloud / NICE CXone — more enterprise contact-center focused

If you only need transcription for recorded audio

You can use:

• OpenAI Whisper API
• Deepgram API
• AssemblyAI API

These handle the transcription part well, but you’d still need a telephony provider for the call recording itself.

Typical setup

1. Telephony provider records the call
2. Recording is saved to storage
3. Audio file is sent to a transcription API
4. Transcript is attached to the support ticket / CRM

Recommendation

• Small/medium team or custom support line: Twilio + transcription API
• Full contact center: Amazon Connect
• Need best transcription quality/real-time captions: Deepgram or AssemblyAI

If you tell me:

• your phone system,
• whether you need live transcription or just after-call,
• and your stack (e.g. Python, Node, Salesforce, Zendesk),

I can recommend the best exact API and architecture.