How to migrate from seven.io to Vonage

seven.io is a German CPaaS platform offering SMS, RCS, WhatsApp and voice APIs on EU-hosted infrastructure, while Vonage (part of Ericsson) is a larger, publicly traded communications-API vendor covering those same channels plus MMS, Viber and Facebook Messenger. On the messaging.dev Score, seven.io rates 42/100 and Vonage 89/100. This guide covers what changes at the API level and how to move your integration across without downtime.

What you gain and what you lose

Channels. Every channel you use on seven.io — SMS, RCS, WhatsApp and voice — also exists on Vonage, so no channel is lost in the move. You gain MMS, Viber and Facebook Messenger. Neither provider supports Telegram, Apple Messages for Business or email.

Compliance. Both hold GDPR and ISO 27001. Vonage additionally carries SOC 2 and HIPAA. No certification is lost.

Data residency. Both offer EU servers. seven.io processes strictly on German/EU infrastructure (“Pure EU Routing”) with no US option and no region choice. Vonage adds US servers, APAC and Australia, and lets you choose data residency — but its default is multi-region rather than EU-only.

Pricing and free credit. Both are pay-as-you-go with no subscription. seven.io is prepaid top-up at a €0.075 base rate per SMS (EU incl. Germany); Vonage is PAYG with volume discounts, around $0.0072 per US SMS segment plus carrier fees — note the currency and per-market differences make these hard to compare directly. Free developer credit rises from €0.50 to €2.

SDKs and API types. Docs quality is “high” on both and both provide a sandbox. Shared SDK languages are PHP, Python, Ruby and Kotlin (plus JavaScript/Node.js). seven.io also ships Go, Rust, Elixir, Swift and .NET SDKs; Vonage instead ships Java and C#. seven.io additionally exposes SMPP and SMTP interfaces, whereas Vonage is REST-only.

Operations. Vonage publishes a 99.95% uptime SLA, direct operator connections and roughly 200-country coverage; seven.io publishes no SLA.

How the request format differs

seven.io quickstart:

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"

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'

Endpoint. seven.io POSTs to https://gateway.seven.io/api/sms. Vonage’s legacy SMS API posts to https://rest.nexmo.com/sms/json, or you can use the newer Messages API at https://api.nexmo.com/v1/messages.

Authentication. This is the biggest change. seven.io authenticates with a single API key in the X-Api-Key header. Vonage’s SMS API expects api_key and api_secret as form parameters in the request body (the Messages API uses JWT auth instead). So you move the key out of the header, add a secret, and — for the Messages API — sign a JWT.

Payload mapping. The message body maps almost 1:1: recipient (to), sender (from) and text (text) use identical field names on both platforms. The seven.io example uses a German MSISDN and Vonage a US one, but both are plain E.164-style numbers. Migrating a basic SMS send therefore means changing the host and auth, not rewriting the payload.

Migration checklist

1. Create a Vonage account and generate your API key + secret (and a JWT/application if you plan to use the Messages API). New accounts include €2 free credit.
2. Map the request fields: to, from and text are unchanged; move your key from the X-Api-Key header to api_key in the body and add api_secret.
3. Re-point your sending code to the new host, and swap the seven.io SDK for an official Vonage SDK if you use one.
4. Re-test in Vonage’s sandbox before sending live traffic (both providers offer one).
5. Re-register your delivery-receipt and inbound webhook URLs in the Vonage dashboard, since callback formats differ.
6. Run both providers in parallel on a subset of traffic and compare delivery and reporting.
7. Cut over once results match, then decommission seven.io.

Watch out for

• REST-only. Vonage drops seven.io’s SMPP and SMTP interfaces, so any SMPP bind or email-to-SMS path must be re-implemented over REST.
• SDK gaps. Official Go, Rust, Elixir and Swift SDKs available on seven.io have no Vonage equivalent; you would call the REST API directly in those languages.
• Residency default. seven.io’s strict EU-only routing becomes a multi-region default on Vonage — enable data-residency choice if EU-only processing is a requirement.
• Two credentials. Unlike seven.io’s single header key, Vonage needs api_key + api_secret (SMS API) or a JWT (Messages API).

For a full side-by-side, see seven.io vs Vonage.