How to migrate from SlickText to Vonage

SlickText is a US- and Canada-focused SMS, MMS, and RCS marketing platform built around mass-texting campaigns, automation, and two-way conversations over a REST API. Vonage is a broader communications-API provider (part of Ericsson) covering SMS, MMS, RCS, WhatsApp, Viber, Facebook Messenger, and voice across roughly 200 countries. On the messaging.dev Score, SlickText rates 38/100 and Vonage 89/100; this guide covers what that gap means in practice when you re-point your sending code.

What you gain and what you lose

Channels. Both providers send SMS, MMS, and RCS, so you lose no channel by moving. You gain WhatsApp, Viber, Facebook Messenger, and voice. Neither offers Telegram, Apple Messages for Business, or email, so those remain unavailable on both sides.

Compliance. Both hold SOC 2 and HIPAA. Vonage additionally lists GDPR and ISO 27001, so you keep every certification SlickText had and add two.

Data residency. SlickText runs on US servers only, with no region choice. Vonage offers US and EU servers plus APAC and Australia, with a data-residency choice.

Pricing and free credit. SlickText uses monthly subscription plans with a fixed pool of rollover credits (from $29/month for 500 credits, $0.058 per SMS) and no free developer credit. Vonage is pay-as-you-go ($0.0072 per US SMS segment plus carrier fees) and includes €2 free trial credit.

Tooling and docs. SlickText ships no official SDKs, has no sandbox, and its docs are rated medium. Vonage provides SDKs for Node.js, Python, PHP, Java, C#, Ruby, and Kotlin, offers a sandbox, and its docs are rated high. Both expose REST APIs. Vonage publishes a 99.95% uptime SLA where SlickText publishes none, and country coverage rises from 2 to about 200.

How the request format differs

SlickText (source):

curl -X POST https://dev.slicktext.com/v1/brands/BRAND_ID/campaigns/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Send From API",
    "body": "Welcome to ACME",
    "status": "send",
    "audience": { "contact_lists": [21] }
  }'

Vonage (target):

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. You move from a brand-scoped campaign URL (https://dev.slicktext.com/v1/brands/{brand_id}/campaigns/) to Vonage’s https://rest.nexmo.com/sms/json (legacy SMS API) or https://api.nexmo.com/v1/messages (Messages API).

Authentication. SlickText uses a Bearer API token in the Authorization header. Vonage’s SMS API instead expects api_key and api_secret sent as request parameters, while the Messages API uses JWT auth — decide which of the two you target before you code.

Payload mapping. The message text moves from SlickText’s JSON body to Vonage’s text. Recipients change shape: SlickText targets an audience via audience.contact_lists (a list of contact-list IDs), whereas Vonage targets a single number in to (E.164). The sender, absent from SlickText’s campaign call, becomes Vonage’s from. SlickText’s name and status fields have no Vonage equivalent, and the content type shifts from JSON to form-encoded parameters.

Migration checklist

1. Create a Vonage account and generate credentials (API key + secret, or a JWT/application for the Messages API); note the €2 trial credit.
2. Map each SlickText field to Vonage: body → text, contact-list audience → per-recipient to, add an explicit from; drop name/status.
3. Re-point your sending code to the new base URL and swap the Bearer header for api_key/api_secret (or JWT).
4. Re-test against Vonage’s sandbox before sending live traffic.
5. Update webhooks and delivery/callback handling to Vonage’s formats.
6. Run both providers in parallel and compare delivery results.
7. Cut over once Vonage delivery is verified.
8. Decommission the SlickText integration and rotate old keys.

For a from-scratch walkthrough, see how to start with Vonage, and the full data sits in the SlickText vs Vonage comparison.

Watch out for

• Pricing model change. You leave predictable monthly subscriptions with rollover credits for pay-as-you-go per-message billing quoted plus carrier fees — budget and cost tracking work differently.
• Lower-level API. Vonage’s SMS API sends to a single recipient rather than a managed contact-list audience, so campaign and list management moves to your side.
• Auth and API choice. Credentials travel as request parameters on the legacy SMS API, and the Messages API requires JWT; pick one path deliberately.
• Still no Telegram, Apple Messages for Business, or email on either provider, so migrating does not unlock those channels.