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It's a split decision.
Choose Bandwidth for enterprise voice and messaging where direct-to-carrier connectivity, SIP trunking, and published U.S. usage rates matter. Choose Sinch if you need a broader mix of messaging channels, email, verification, developer tools, or packaged SMS plans. Sinch Functions starts free, but its API usage rates and limits are not published. Both offer usage-based APIs, and neither’s listed materials establish open-source licensing or self-hosting options.
01Side by side
| Bandwidth Communications APIs | Sinch | |
|---|---|---|
| Pricing model | Usage-based API rates listed for messaging and voice | Usage-based APIs; Functions compute and messaging charged |
| Free tier | No free plan listed | Functions starts free; 14-day trial listed |
| API and SDKs | Programmable voice, messaging, authentication, and SIP trunking | Messaging, voice, email, verification APIs; SDKs listed |
| CLI and docs | Homepage focuses on APIs and communications services | Documentation, SDKs, Functions, and CLI listed |
| Integrations | Salesforce Contact Center, Webex, Google, Genesys, Five9, Teams | Adobe, Emarsys, SAP, HubSpot, Shopify |
| Deployment model | Direct-to-carrier connectivity, PSTN, and global SIP trunking | Communications infrastructure with number provisioning and routing |
| Platforms | Web | Web |
| Limits and scaling | Usage rates published; SIP trunking requires a quote | SMS bundles listed; API usage limits not published |
Bandwidth Communications APIs Choose Bandwidth Communications APIs if
- Choose Bandwidth Communications APIs if direct-to-carrier connectivity is central.
- Choose Bandwidth Communications APIs if you need global SIP trunking.
- Choose Bandwidth Communications APIs if published U.S. API rates help budgeting.
Sinch Choose Sinch if
- Choose Sinch if your stack needs SMS, RCS, MMS, WhatsApp, and email.
- Choose Sinch if you want developer documentation, SDKs, and a CLI listed.
- Choose Sinch if Functions' free starting tier or bundled SMS plans fit.
02Pricing at real usage
Bandwidth has no free plan listed. Its usage-based U.S. SMS rates include 10DLC at $0.004/SMS and $0.015/MMS, short code at $0.008/SMS and $0.020/MMS, and toll-free at $0.007/SMS and $0.020/MMS. Local outbound voice is $0.0100/minute and inbound is $0.0055/minute; SIP trunking requires a quote.
Sinch Functions starts free, then charges for compute time; SMS and voice are billed per message or minute, but API rates and usage limits are not published. Sinch Engage lists monthly bundles from $99 for 3,000 SMS to $2,399 for 150,000 SMS. Its plans add users and features at higher tiers, and a 14-day trial is listed. Model API costs with your expected traffic before comparing them with Engage’s bundled prices.
03API, SDKs and integration
Bandwidth offers programmable voice and messaging APIs, including SMS and RCS, alongside authentication and SIP trunking. Its homepage highlights carrier connectivity and enterprise integrations with Salesforce Contact Center, Webex Calling, Google, Genesys, Five9, and Microsoft Teams. It does not specify SDK languages or CLI details on that homepage, so confirm the supported libraries and implementation paths with Bandwidth before choosing a stack.
Sinch lists APIs for messaging, voice, email, verification, and numbers. Its developer menu includes documentation for messaging, voice and video, email, verification, and connectivity, plus SDKs, Functions, a CLI, GitHub, and API status. The homepage lists platform ecosystems including Adobe, Emarsys, SAP, HubSpot, and Shopify. Neither homepage specifies SDK languages, so check Sinch’s documentation for the language and API coverage your application needs.
04Open source, self-hosting and lock-in
Neither vendor’s listed product information specifies an open-source license or a self-hosting option. Treat both as vendor-provided communications services rather than assuming you can run the API infrastructure in your own environment.
The integration and migration questions differ. Bandwidth emphasizes direct-to-carrier connections, PSTN connectivity, and SIP trunking; replacing those services may require changes to carrier routing and voice configuration. Sinch spans messaging, email, voice, verification, and applications, so moving a wider set of channels could involve more endpoints and workflows. Neither vendor publishes data-export terms in the information summarized here. Before committing, ask about exporting numbers, message records, templates, and configuration, as well as number portability, contract terms, and the steps required to move traffic to another provider.
Questions people ask
Is Bandwidth a VoIP service?
Bandwidth provides programmable voice APIs, global SIP trunking, and PSTN connectivity, so it can support VoIP and enterprise calling architectures. It is broader than a standalone VoIP phone service: its communications offering also includes messaging, emergency communications, authentication, and carrier connectivity.
What is the Sinch API?
Sinch offers communication APIs for messaging, voice, email, verification, and numbers. Its messaging channels include SMS, RCS, MMS, and WhatsApp. Sinch also lists applications, developer documentation, SDKs, Functions, and a CLI alongside its APIs.
Which SMS API is the best?
It depends on your channel and infrastructure needs. Bandwidth lists U.S. SMS and MMS rates and emphasizes carrier connectivity. Sinch supports SMS alongside RCS, MMS, and WhatsApp, and offers a free starting point for Functions. Compare delivery needs, supported integrations, and total usage costs for your traffic.
How much does Bandwidth charge for SMS messaging?
Bandwidth lists U.S. 10DLC at $0.004 per SMS and $0.015 per MMS. U.S. short-code rates are $0.008 per SMS and $0.020 per MMS; toll-free rates are $0.007 per SMS and $0.020 per MMS. The listed pricing is usage-based.