Microsoft Azure Communication Services Call Automation vs Amazon Chime SDK PSTN Audio

Microsoft Azure Communication Services Call Automation8.9Visit Amazon Chime SDK PSTN Audio8.8Visit

Higher score Microsoft Azure Communication Services Call Automation #6 in Voice APIs 8.9/10 Paid ✓ 4 of 5 features Visit Azure

vs

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

• Microsoft Azure Communication Services Call Automation fits best

  Azure teams automating calls with event workflows

• Amazon Chime SDK PSTN Audio fits best

  AWS developers adding PSTN call flows

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature	Microsoft Azure Communication Services Call Automation 8.9/10 Visit ↗	Amazon Chime SDK PSTN Audio 8.8/10 Visit ↗
At a glance
Editor score	8.9	8.8
Ranking	#6 in Voice APIs	#7 in Voice APIs
Best for	Azure teams automating calls with event workflows	AWS developers adding PSTN call flows
Pricing model	Paid	Paid
Starting price	Not checked yet	$0.002/unit usage-based
Free plan	—	—
Free trial	—	—
Deployment	Cloud	Cloud
Support	Docs, Community	Docs, Community
Integrations	1 integrations	4 integrations
Built for	Small business, Mid-market, Enterprise	Mid-market, Enterprise
Features Microsoft Azure Communication Services Call Automation 4/5 · Amazon Chime SDK PSTN Audio 5/5
Inbound calling	✓	✓
Outbound calling	✓	✓
Phone number support	✓	✓
SIP support	Not checked yet	✓ (best)
Call recording	✓	✓
Specs
Concurrent call limit	Not checked yet	10 calls
SDK languages	C#, Java, JavaScript, Python	JavaScript, Swift, Objective-C, Kotlin, Java, C++
Our review
Pros	Inbound and outbound calling with webhook-driven event control Speech, DTMF, streaming, transcription, recording, and transfers SIP Direct Routing connects existing telephony infrastructure	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	API-only delivery requires development work Outbound concurrency defaults to 2 calls per phone number PSTN pricing varies by destination and region	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	Microsoft Azure Communication Services Call Automation is a server-side API and SDK offering for developers building programmable voice workflows over VoIP and the public switched telephone network. It supports inbound call answering,… 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

• Microsoft Azure Communication Services Call Automation — where it wins

  • Inbound and outbound calling with webhook-driven event control
  • Speech, DTMF, streaming, transcription, recording, and transfers
  • SIP Direct Routing connects existing telephony infrastructure

  Where it doesn't

  • API-only delivery requires development work
  • Outbound concurrency defaults to 2 calls per phone number
  • PSTN pricing varies by destination and region

• 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

• Microsoft Azure Communication Services Call Automation8.9/10 · Paid

  A capable Azure voice API for event-driven call automation with usage-based pricing.

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

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

  Visit AWSFull verdict →