How to migrate from seven.io to Telnyx

seven.io is a German CPaaS platform providing SMS, RCS, WhatsApp and voice APIs on German-hosted infrastructure. Telnyx is a licensed US telecom carrier offering a CPaaS platform for SMS, MMS, RCS, WhatsApp, voice and email over its own private global IP network. On the messaging.dev Score, seven.io rates 42/100 and Telnyx 78/100; this guide walks through the concrete API and capability differences you will hit when moving traffic between them.

What changes when you move

Channels. You keep SMS, RCS, WhatsApp and voice, and you gain MMS and email. You lose no channels in the move — neither provider offers Viber, Facebook Messenger, Telegram or Apple Messages for Business.

Compliance. Both are GDPR-compliant and ISO 27001 certified. Telnyx additionally holds SOC 2 and HIPAA, which seven.io does not — relevant if you handle regulated or health data.

Data residency. seven.io processes on German/EU infrastructure only (“Pure EU Routing”): EU servers, no US presence, no region choice. Telnyx offers both EU and US servers, data-residency choice, plus Asia-Pacific and South America regions.

Pricing. Both are pay-as-you-go. seven.io is prepaid — you top up a balance and pay per message with no monthly fee, starting at €0.075 per SMS (base rate incl. Germany and most EU). Telnyx bills per message part, with volume discounts and custom contracts, starting at $0.004 per outbound SMS part (US, plus carrier fees). Expect USD billing and per-segment costs on long messages.

Free credit. seven.io includes €0.50 free test credit; Telnyx has no free developer credit.

SDKs. Both ship official SDKs for PHP, Python, Ruby, Go and .NET (seven.io’s JavaScript maps to Telnyx’s Node.js). Telnyx adds Java. seven.io also offers Rust, Kotlin, Elixir and Swift, which Telnyx does not.

Sandbox & docs. Both rate high on documentation quality. seven.io provides a sandbox with separate test API keys; Telnyx does not.

How the request format differs

seven.io:

curl -X POST https://gateway.seven.io/api/sms \
    -H "X-Api-Key: YOUR_API_KEY" \
    -H "Accept: application/json" \
    -d "to=49176123456789" \
    -d "from=AcmeInc" \
    -d "text=hello world"

Telnyx:

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!"
  }'

Three things change. First, the endpoint: https://gateway.seven.io/api/sms becomes https://api.telnyx.com/v2/messages. Second, the authentication: seven.io sends the key in an X-Api-Key header, while Telnyx expects a Bearer token in the Authorization header (Authorization: Bearer YOUR_API_KEY). Third, the payload shape: seven.io takes form-encoded fields, whereas Telnyx takes a JSON body with Content-Type: application/json. The field names map cleanly — to → to (recipient), from → from (sender), text → text (body) — but two conventions differ: Telnyx expects E.164 numbers with a leading +, and the from value is typically a number provisioned on your Telnyx account rather than an alphanumeric sender ID like AcmeInc.

Migration checklist

1. Create a Telnyx account (self-onboarding) and generate an API key from the dashboard.
2. Provision a sending number (or messaging profile) on Telnyx to use as your from.
3. Map your request fields: switch form-encoded params to a JSON body, keep to/from/text, and normalize recipients to E.164 with a leading +.
4. Re-point your sending code: update the base URL to https://api.telnyx.com/v2/messages and swap the X-Api-Key header for Authorization: Bearer.
5. Re-test. Telnyx has no sandbox, so test against live credentials with a low-volume number and small spend rather than a test environment.
6. Update webhooks and delivery callbacks to Telnyx’s delivery-report format and endpoints.
7. Run both providers in parallel, splitting a fraction of traffic to Telnyx to compare delivery and cost.
8. Cut over once delivery, latency and billing look right, then retire the seven.io path.

For a from-scratch walkthrough of the target API, see how to start with Telnyx, and for a full side-by-side see the seven.io vs Telnyx comparison.

Watch out for

• No sandbox. seven.io’s test environment has no Telnyx equivalent; plan live low-volume testing instead.
• No free credit. You lose seven.io’s €0.50 test credit — budget real funds from the first test.
• SDK gaps. If you use seven.io’s Rust, Kotlin, Elixir or Swift SDK, Telnyx offers no official equivalent; you will call the REST API directly.
• Residency defaults. Moving from EU-only “Pure EU Routing” to a US-headquartered global carrier means you must explicitly configure EU residency if strict EU processing is a requirement.
• Billing model. Telnyx bills per message part plus carrier fees in USD, so long or multipart messages can cost differently than seven.io’s per-message EUR pricing.