Channels
A JSON dump tells you the send succeeded. It does not tell you the template renders with a stray comma, that the OTP is buried below the signature, or that the push title is truncated on a lock screen. So Notify-Sim draws the screen.
SmartPing SPARC · MSG91 · Route Mobile · Kaleyra · Exotel · Twilio · Infobip · Amazon SNS · generic REST
Meta WhatsApp Cloud API (+ template registry) · Gupshup
SMTP gateway · SendGrid v3 · Amazon SES v2
Ravi Naidu - Tower C site office. Tap for directions.
Expo Push (+ receipts) · FCM v1
Provider matrix
Each row is the real provider's own path and credential style. Change the host, keep the client library.
| Provider | Channel | Endpoint you point at | Credential |
|---|---|---|---|
| SmartPing SPARC | SMS | GET /fe/api/v1/send | username + password |
| Exotel | SMS | POST /v1/Accounts/{key}/Sms/send | HTTP basic |
| MSG91 | SMS | POST /api/v5/flow | authkey header |
| Route Mobile | SMS | GET /bulksms/bulksms | username + password |
| Kaleyra | SMS | POST /v1/{key}/messages | api-key header |
| Twilio | SMS | POST /2010-04-01/Accounts/{key}/Messages.json | HTTP basic |
| Infobip | SMS | POST /sms/2/text/advanced | Authorization: App |
| Amazon SNS | SMS | POST /aws/sns (Action=Publish) | access key id |
| Meta WhatsApp Cloud | POST /v25.0/{phone_id}/messages | bearer secret | |
| Any /vNN.N path is accepted, so point your client at the Graph version it already uses - v23, v24, v25 - and nothing in your code changes when Meta moves on. | |||
| Meta template registry | POST /v25.0/{waba_id}/message_templates | bearer secret | |
| Gupshup | POST /wa/api/v1/msg | apikey header | |
| SendGrid v3 | POST /v3/mail/send | bearer secret | |
| Amazon SES v2 | POST /v2/email/outbound-emails | access key id | |
| SMTP gateway | smtp.notify-sim.io:2587 | AUTH LOGIN / PLAIN | |
| Expo Push | Push | POST /--/api/v2/push/send | bearer secret |
| FCM v1 | Push | POST /v1/projects/{key}/messages:send | project key in path |
| Anything else | All four | POST /v1/capture/{channel} | API key |
Missing your gateway? Tell us which one - provider emulation is the fastest-moving part of the roadmap.
Details that matter in practice
Email attachments are captured with their bytes, so a cost sheet opens from the inbox and a PDF is byte-identical to the one your app produced.
A WhatsApp template send carries a name and parameters. Register the approved body once and the inbox shows the sentence your customer will read.
Desktop reading pane or phone, with HTML, plain text and raw source side by side - because "it looked fine in Gmail" is not a test.
Messages to the same recipient group into one conversation, so an OTP resend or a reminder sequence reads the way the customer received it.
WhatsApp images, documents and stickers render as cards with the real filename, and open the exact file your signed link points to.
The inbox streams. Run your flow on one screen and watch each message appear on the other, in order, with its status changing.
Start in about two minutes
Create a project, copy the environment block for your stack, and run the flow you were about to test anyway. The free tier does not expire and needs no card.