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Prelude Transactional SMS API

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What Prelude Transactional SMS API is

Prelude Transactional SMS API sends automated service messages such as one-time passcodes, order confirmations, payment notifications, and reminders. Its REST API uses POST requests for individual or bulk sends and supports delivery status, webhooks, and two-way messaging. Prelude says regional and carrier routing reaches more than 230 countries. The API handles language and encoding automatically and accepts dynamic fields including name, language, and time zone. Monitoring includes delivery receipts, real-time status, analytics, cost monitoring, and detailed API logs. Integration resources include technical documentation, code samples, sandbox testing, dashboard test numbers, and free credits for real-message testing. Prelude advertises average delivery under three seconds, delivery above 98%, and a 99.95% uptime SLA. It states that communications use HTTPS/TLS encryption and token-based authentication, with hosting in U.S. and EU data centers. Its Trust Center lists ISO 27001:2022 and SOC 2 Type 1 and Type 2 reports. The paid pay-as-you-go plan charges €0.05 per verification; SMS charges vary by country.

Who it suits

Prelude suits developers adding automated SMS verification, notifications, reminders, or transactional updates to applications. It provides REST integration resources, monitoring, and support through chat, email, and Slack.

What it does well

  • REST API supports single and bulk sends
  • Delivery to over 230 countries
  • Real-time status and delivery receipts
  • Sandbox and free testing credits
  • Webhooks and two-way messaging

What to know first

  • SMS message costs vary by country
  • No free plan
  • 0.05 EUR charged per verification
  • Service is API and web based

Plans

PlanBilled and limitsPrice
Pay as you goPer verification; SMS message costs are additional and vary by country. · Country- and volume-based pricing · No hidden fees or subscriptions€0.05, paid once

As prelude.so lists them, read 4 Oct 2026. The maker's own page has the final word.

Verdict

Prelude provides a transactional SMS API with international routing, delivery monitoring, testing resources, and stated security controls. Its pay-as-you-go model charges per verification plus country-dependent SMS message costs.

Facts from Prelude Transactional SMS API's own pages

API
The API uses REST and supports single or bulk message sending through POST requests. · prelude.so, 4 Oct 2026
Certifications
Prelude’s Trust Center lists ISO 27001:2022 and SOC 2 Type 1 and Type 2 reports. · trust.prelude.so, 4 Oct 2026
Founded
2022 · prelude.so, 28 Sept 2026
Integration resources
Prelude offers technical documentation, code samples, sandbox testing, dashboard test numbers, and free credits for real message testing. · prelude.so, 4 Oct 2026
Message handling
The API automatically manages language and encoding and supports dynamic fields such as name, language, and time zone. · prelude.so, 4 Oct 2026
Monitoring
The service provides delivery receipts, real-time message status, analytics, cost monitoring, and detailed API logs. · prelude.so, 4 Oct 2026
Performance
Prelude advertises average delivery under three seconds, a delivery rate above 98%, and a 99.95% uptime SLA. · prelude.so, 4 Oct 2026
Pricing model
Pricing depends on destination country and sending volume, with no setup fees or minimum commitment stated on the product page. · prelude.so, 4 Oct 2026
Privacy and compliance
Prelude says its infrastructure complies with GDPR and U.S. privacy standards and that only essential data is stored for delivery tracking. · prelude.so, 4 Oct 2026
Routing
Prelude says it routes messages by region and carrier and supports delivery to over 230 countries. · prelude.so, 4 Oct 2026
Security
Prelude states that communications use HTTPS/TLS encryption and token-based API authentication, with hosting in U.S. and EU data centers. · prelude.so, 4 Oct 2026
Support
Prelude offers human support via chat, email, and a dedicated Slack channel for integration, deliverability, webhook, and troubleshooting help. · prelude.so, 4 Oct 2026
What it does
Prelude’s Transactional SMS API sends automated service messages such as OTPs, order confirmations, payment notifications, and reminders. · prelude.so, 4 Oct 2026

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