How to migrate from Telnyx to Vonage

Telnyx is a licensed telecom carrier that runs a CPaaS platform with APIs for SMS, MMS, RCS, WhatsApp, voice, and email over its own private global IP network. Vonage (part of Ericsson) is a communications-API platform covering SMS, voice, video, and messaging. On the messaging.dev Score, Telnyx rates 78/100 and Vonage 89/100 — this guide walks through what actually changes when you re-point your sending code from one to the other.

What you gain and what you lose

Both providers cover the core messaging channels identically: SMS, MMS, RCS, WhatsApp, and voice are all supported on each. The differences sit at the edges:

• Channels you gain: Viber and Facebook Messenger — both supported on Vonage but not on Telnyx.
• Channel you lose: Email. Telnyx exposes an email API; Vonage does not. If any of your flows send email through Telnyx, you will need a separate provider for that.

Compliance is a wash: both carry GDPR, ISO 27001, SOC 2, and HIPAA alignment. Data residency is equivalent too — both run US and EU servers and let you choose a region. Both also offer self-onboarding, high-quality docs, direct operator connections, and pay-as-you-go pricing with volume discounts.

A few operational differences matter:

• Free credit: Vonage includes €2 of free trial credit; Telnyx has none.
• Sandbox: Vonage provides a test environment; Telnyx does not.
• Pricing level: Telnyx starts around $0.004 per US SMS part; Vonage is approximately $0.0072 per US SMS segment (both plus carrier fees).
• SDKs: Both ship seven official SDKs. Moving to Vonage you gain Kotlin and lose Go; C# on Vonage covers the .NET stack Telnyx serves with its .NET SDK. Node.js, Python, PHP, Java, and Ruby exist on both.
• API protocols: Telnyx exposes both REST and SMPP; Vonage is REST-only, so an SMPP binding will not carry over.
• Coverage: Vonage lists 200 countries to Telnyx’s 130, with a 99.95% uptime SLA versus Telnyx’s 99.99%.

How the request format differs

Telnyx quickstart:

curl -X POST https://api.telnyx.com/v2/messages \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "from": "+15551234567",
    "to": "+15559876543",
    "text": "Hello, world!"
  }'

Vonage quickstart:

curl -X POST 'https://rest.nexmo.com/sms/json' \
  -d 'api_key=YOUR_API_KEY' \
  -d 'api_secret=YOUR_API_SECRET' \
  -d 'from=Vonage' \
  -d 'to=15551234567' \
  -d 'text=Hello from Vonage'

Three things change:

• Endpoint: https://api.telnyx.com/v2/messages becomes https://rest.nexmo.com/sms/json (the legacy SMS API) or https://api.nexmo.com/v1/messages (the Messages API).
• Authentication: Telnyx uses a Bearer API key in the Authorization header. Vonage’s SMS API instead takes an api_key + api_secret pair as request parameters, while the Messages API uses JWT auth. The credential moves out of the header and into the request body.
• Payload shape: Telnyx posts a JSON body; the Vonage SMS API takes form-encoded fields. The field names line up — from, to, and text exist on both — but note the sender: Telnyx’s example uses an E.164 number, while Vonage’s uses an alphanumeric sender ID (Vonage). Recipient to and body text map one-to-one.

Migration checklist

1. Create a Vonage account and generate your API key + secret (or a JWT application for the Messages API). See how to start with Vonage.
2. Map the request fields: keep from/to/text, switch from a JSON body to form-encoded parameters, and move the credential from the Authorization header to api_key/api_secret.
3. Re-point your sending code at the new endpoint and swap in the official SDK if you use one.
4. Re-test against Vonage’s sandbox before sending live traffic.
5. Update your delivery-receipt and inbound webhooks to Vonage’s callback format.
6. Run both providers in parallel and compare delivery on real traffic.
7. Cut over once Vonage’s numbers hold, then decommission Telnyx.

Watch out for

• You lose the email channel — Telnyx has an email API, Vonage does not.
• No SMPP — Vonage is REST-only; high-volume SMPP bindings will not migrate.
• Higher per-message SMS price — roughly $0.0072 vs $0.004 per US message on the published starting rates.
• Slightly lower uptime SLA — 99.95% versus Telnyx’s 99.99%.

For a full side-by-side, see the Telnyx vs Vonage comparison.