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Issue a request to the URL https://gateway.sms77.io/api and send the needed variables optionally as HTTP GET or HTTP POST parameters. For security reasons and also when sending larger items to many recipients or for longer SMS texts, we recommend calling via POST.

Alternatively, you can also transfer the data directly as JSON in the post body. To do this, set the header content-type: application/json – you should also set accept: application/json to get JSON as response.

Please make sure that all parameters are transmitted in a URL-encoded form before you send the request.

API Limits


All our interfaces are limited to a maximum of 50 connections per second. Please bundle your requests accordingly, e.g. by sending several SMS in one request. If you still want to send more requests per second, please use keep-alive of the connection. This way you also avoid the overhead of a connection setup. The maximum number of requests accepted per connection is 500 and the timeout before the connection is closed is 3s.


To secure your account, we have implemented the following security mechanisms:

1. API Key

Access to the API is only possible with your API key. If a third party accesses your account, they will still not be able to log in. You can find your API Keys in your login under the Developer item in the API Keys section. You can add different keys via the green plus icon.

2. IP Whitelist

To increase security, you can enter one or more IP addresses in your login under Developer in the API Keys section, from which the HTTP API may be accessed via your account. You can access the settings by clicking on the blue cogs icon.
It is also possible to specify a host name, which is then resolved and checked by the API during the call. Several values ​​can be entered comma-separated. Please note that the whitelist only makes sense in combination with a static IP address.

3. Transport Layer Security (TLS)

The transmission of data to our API is TLS encrypted. We support the common versions TLS v1.2 and TLS v1.3. The older versions TLS 1.0 and 1.1 and SSL2/SSL3 are not supported. Calling our API without encryption is no longer possible since January 2022.