Twilio Elastic SIP Trunking vs Amazon Chime SDK PSTN Audio

Twilio Elastic SIP Trunking9.2Visit Amazon Chime SDK PSTN Audio8.8Visit

Higher score Twilio Elastic SIP Trunking #2 in Voice APIs 9.2/10 Paid ✓ 0 of 5 features Visit Twilio

vs

Amazon Chime SDK PSTN Audio #7 in Voice APIs 8.8/10 Paid ✓ 5 of 5 features Visit AWS

• Twilio Elastic SIP Trunking fits best

  Businesses connecting SIP infrastructure to PSTN

• Amazon Chime SDK PSTN Audio fits best

  AWS developers adding PSTN call flows

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Side by side

Feature	Twilio Elastic SIP Trunking 9.2/10 Visit ↗	Amazon Chime SDK PSTN Audio 8.8/10 Visit ↗
At a glance
Editor score	9.2	8.8
Ranking	#2 in Voice APIs	#7 in Voice APIs
Best for	Businesses connecting SIP infrastructure to PSTN	AWS developers adding PSTN call flows
Pricing model	Paid	Paid
Starting price	—	$0.002/unit usage-based
Free plan	—	—
Free trial	—	—
Deployment	Cloud	Cloud
Platforms	Web	Web
Integrations	4 integrations	4 integrations
Features Twilio Elastic SIP Trunking 0/5 · Amazon Chime SDK PSTN Audio 5/5
Inbound calling	Not checked yet	✓ (best)
Outbound calling	Not checked yet	✓ (best)
Phone number support	Not checked yet	✓ (best)
SIP support	Not checked yet	✓ (best)
Call recording	Not checked yet	✓ (best)
Specs
Concurrent call limit	Not checked yet	10 calls
SDK languages	Not checked yet	JavaScript, Swift, Objective-C, Kotlin, Java, C++
Our review
Pros	Handles inbound origination and outbound termination to the PSTN Includes unlimited call concurrency and TLS/SRTP Secure Trunking Supports recording, emergency addresses, and disaster recovery URLs	Inbound and outbound calling with provisioned and toll-free numbers Lambda-controlled flows with DTMF, prompts, routing, and bridging Recording, noise suppression, and integrations across AWS services
Cons	Voice usage is billed per minute in addition to phone-number charges Geographic route pricing varies by country Focused on SIP-to-PSTN connectivity rather than a full voice application API	API-only coverage requires development work for end-user applications Usage-based billing spans calling, phone numbers, and connected AWS services The default regional active-call quota is 10 concurrent calls
Our verdict	Twilio Elastic SIP Trunking connects IP-based communications infrastructure, such as an IP-PBX or session border controller, to the public switched telephone network. It supports inbound and outbound calling, making it a fit for contact… Read the review →	Amazon Chime SDK PSTN Audio is an API service for developers building serverless telephony applications on AWS. It supports inbound calls on provisioned DID/DDI and toll-free numbers, outbound calls to landline and mobile numbers in over… Read the review →

Strengths and trade-offs

• Twilio Elastic SIP Trunking — where it wins

  • Handles inbound origination and outbound termination to the PSTN
  • Includes unlimited call concurrency and TLS/SRTP Secure Trunking
  • Supports recording, emergency addresses, and disaster recovery URLs

  Where it doesn't

  • Voice usage is billed per minute in addition to phone-number charges
  • Geographic route pricing varies by country
  • Focused on SIP-to-PSTN connectivity rather than a full voice application API

• Amazon Chime SDK PSTN Audio — where it wins

  • Inbound and outbound calling with provisioned and toll-free numbers
  • Lambda-controlled flows with DTMF, prompts, routing, and bridging
  • Recording, noise suppression, and integrations across AWS services

  Where it doesn't

  • API-only coverage requires development work for end-user applications
  • Usage-based billing spans calling, phone numbers, and connected AWS services
  • The default regional active-call quota is 10 concurrent calls

• Twilio Elastic SIP Trunking9.2/10 · Paid

  A focused SIP-to-PSTN service with secure trunking and pay-as-you-go voice charges.

  Visit TwilioFull verdict →
• Amazon Chime SDK PSTN Audio8.8/10 · Paid

  A focused AWS building block for developers creating programmable PSTN call flows.

  Visit AWSFull verdict →