The complexity of sending SMS makes choosing the right provider crucial. To ensure your messages reach customers reliably, you need partners who have established direct carrier connections, understand local regulations, and can navigate the technical intricacies of global SMS delivery while maintaining high deliverability rates and reasonable costs.

How to evaluate SMS providers

All SMS notification providers are not created equal. Choosing the right one for your company will depend on several factors.

Pricing and value

When you are sending high volumes of messages, the difference between $0.007 per message and $0.008 can be significant. Make sure you find a provider that meets your pricing expectations and always calculate your expected costs based on your sending volume.

You’ll also want to consider setup fees, monthly minimums, and hidden costs like feature add-ons or compliance fees. SMS pricing can vary based on a number of things, including send volume, destination countries, message types (transactional vs. promotional), and more.

However, the cheapest provider isn't always the best value. You also need to factor in deliverability rates and support quality when calculating true cost per successful delivery.

Developer experience

A great SMS API should be simple to integrate but powerful enough to handle complex use cases. Look for providers offering comprehensive SDKs in your preferred languages, clear documentation with code examples, and good testing environments (necessary when failures can result in you being banned from sending SMS). Some nice-to-have features to look for are webhook support for delivery receipts, idempotency keys to prevent duplicate sends, and detailed error messages.

Advanced features

Beyond basic sending capabilities, you may want an SMS provider that supports other key features:

  • Two-way messaging support.
  • Number pooling to avoid rate limits.
  • Message concatenation for long texts.
  • SMPP connections for high-volume sending.
  • Intelligent routing to optimize delivery rates.
  • Automatic failover between carriers.
  • Real-time analytics.

The top SMS providers

Below is a quick rundown of the top push notification providers available, but check out Knock’s full post for an in-depth breakdown of each solution.

Knock

  • Strengths: Developer-first design, enterprise-grade scalability, comprehensive docs and multi-language SDKs.
  • Weaknesses: No hobby tier between free and $250/month Starter.
  • Pricing: Free tier (10K notifications/month); Starter at $250/month (50K notifications); Enterprise custom pricing.

Twilio

  • Strengths: Industry-leading developer experience with excellent documentation, 180+ country reach through direct carrier connections, comprehensive feature set including Verify service for OTP, unified platform for SMS/MMS/WhatsApp/voice/email, 99.95% uptime SLA.
  • Weaknesses: Premium pricing (among the most expensive), complex advanced features have steep learning curves, free support tier lacks phone access and SLA, unclear error messages for some carrier-specific issues.
  • Pricing: US: $0.0083 per message (outbound/inbound); international rates vary (e.g., Kenya: $0.20); additional costs for A2P 10DLC registration and phone support ($250/month).

Amazon SNS

  • Strengths: Enterprise-scale infrastructure on AWS, high durability and reliability, seamless AWS ecosystem integration, robust IAM and KMS security.
  • Weaknesses: Complex setup for AWS newcomers, feature overhead for push-only use cases, fragmented pricing across service components.
  • Pricing: Free tier with 1M notifications; $0.50 per million thereafter (additional AWS service charges apply).

Sinch

  • Strengths: Direct carrier access and SS7 connectivity, tier-1 aggregator status through acquisitions (CLX, Mblox), enterprise-grade monitoring and SMS firewall services, unified Conversation API for multiple channels, strong compliance expertise.
  • Weaknesses: Complex setup with enterprise-focused design, limited transparency in pricing (requires sales negotiation), sparse community resources, support quality varies significantly by account size.
  • Pricing: Custom pricing requiring sales contact; bulk discounts available for high-volume senders; generally competitive with negotiation.

MessageBird

  • Strengths: Rock-bottom SMS pricing, visual Flow Builder for no-code workflow creation, unified omnichannel platform (SMS, WhatsApp, email, voice), strong European carrier connections, built-in fallback logic between channels.
  • Weaknesses: Platform complexity for SMS-only use cases, diluted focus on SMS features, documentation and support lag behind competitors, additional fees for full platform features can increase costs.
  • Pricing: US: $0.00331 outbound, $0.003 inbound; pricing varies by country; competitive rates to undercut major providers.

Vonage

  • Strengths: Simple JSON-over-HTTP API design, adaptive routing with automatic carrier failover, built-in Verify API for 2FA/OTP, competitive pricing with transparent structure, Number Insight API for validation.
  • Weaknesses: Documentation quality trails market leaders, basic platform analytics without ML optimization, minimal dashboard tools, premium support expensive ($3,300+/month for 24/7 access).
  • Pricing: US: $0.00846 outbound, $0.00679 inbound; free trial with restrictions; passes through 10DLC carrier fees.

MessageMedia

  • Strengths: Business-focused with visual dashboards, managed 10DLC compliance, built-in automation rules and triggers, native integrations with HubSpot/Salesforce/Shopify, visual inbox for two-way conversations.
  • Weaknesses: Higher pricing than infrastructure providers, lacks advanced telecom features (no SIP, short codes), campaign workflows require UI rather than API, smaller developer community.
  • Pricing: US: $0.04 per message plus carrier surcharges ($0.0025-$0.0050); custom quotes for 40,000+ monthly messages.

Plivo

  • Strengths: Lowest cost reliable SMS infrastructure, 99.99% uptime SLA, Twilio-compatible API for easy migration, simple Verify API without extra fees, smart routing across direct carrier connections.
  • Weaknesses: Limited to core SMS/voice features, no native support for WhatsApp or other channels, basic web dashboard, sparse community resources compared to competitors.
  • Pricing: US: $0.007 outbound, free inbound; pay-as-you-go with no minimums; automatic volume discounts for high usage.

Telnyx

  • Strengths: Private fiber network infrastructure, 10x higher throughput (10 MPS vs typical 1 MPS), roughly half Twilio's pricing, free 24/7 expert support, self-serve number porting and management.
  • Weaknesses: Steeper learning curve with telecom concepts, smaller ecosystem with fewer third-party resources, occasional latency during peak periods reported by some high-volume users.
  • Pricing: US: $0.004 per message (outbound/inbound); automatic tiered discounts above 100M messages/month; includes free 24/7 support.

Africa’s Talking

  • Strengths: Unbeatable pricing for African markets (10x lower than competitors), exceptional local developer support and community, handles country-specific compliance, complementary APIs for USSD/Airtime/Mobile Money.
  • Weaknesses: Limited to African markets primarily, expensive international rates ($0.04), basic feature set without multi-channel orchestration, throughput constraints for massive campaigns.
  • Pricing: Kenya: KES 0.8 (~$0.0053) down to KES 0.4 ($0.0027) with volume; international: $0.04; pay-as-you-go with no expiry.

MailerSend

  • Strengths: Seamless integration with email infrastructure, unified API and dashboard for email/SMS, developer-friendly documentation, clean implementation for existing MailerSend users.
  • Weaknesses: North America only (US and Canada), transactional-only policy (no marketing), higher pricing at scale, toll-free numbers only (no short codes or 10DLC).
  • Pricing: Starter plan includes 100 SMS monthly; overages at $0.014 per SMS; must purchase email plan to access SMS features.

Send SMS notifications with Knock

Building a production-ready SMS notification system requires juggling carrier relationships, compliance requirements, delivery optimization, and cost management, all while maintaining the reliability your users expect for critical messages. Whether you're sending authentication codes or shipping updates, the complexity scales faster than most teams anticipate.

That's why we built Knock to handle the SMS infrastructure complexity so you can focus on crafting the right messages for your users. With built-in compliance tools, automatic link tracking, unified preference management, and seamless failover to other channels, you get enterprise-grade SMS notifications without the enterprise-grade headaches.

Whether you’re planning to send notifications across many channels or only SMS, Knock can help. If you'd like to try it out, you can sign up for a free account or chat with our team. 👋