To install the Java SDK, add the following dependency to your project:
Gradle
implementation 'com.resend:resend-java:+'Maven
<dependency>
<groupId>com.resend</groupId>
<artifactId>resend-java</artifactId>
<version>LATEST</version>
</dependency>
First, you need to get an API key, which is available in the Resend Dashboard.
package com.resend; import com.resend.services.emails.model.*; import com.resend.core.provider.AuthenticationProvider; import com.resend.core.provider.impl.AuthenticationProviderStandard; import com.resend.services.emails.ResendEmails; public class Main { public static void main(String[] args) { Resend resend = new Resend("re_123"); CreateEmailOptions params = CreateEmailOptions.builder() .from("Me <[email protected]>") .to("to@example", "[email protected]") .cc("[email protected]", "[email protected]") .bcc("[email protected]", "[email protected]") .replyTo("[email protected]", "[email protected]") .text("Hello, world!") .subject("Hello from Java!") .build(); try { CreateEmailResponse data = resend.emails().send(params); System.out.println(data.getId()); } catch (ResendException e) { e.printStackTrace(); } } }
new Resend("re_123") uses sensible defaults. Use Resend.builder() to set a proxy, timeouts or a custom base URL:
import com.resend.Resend; import java.net.InetSocketAddress; import java.net.Proxy; import java.time.Duration; // 1. Configure the proxy server Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("your.proxy.host", 8080)); // 2. Add the proxy and any other options to the builder, then build the client Resend resend = Resend.builder() .apiKey("re_123") .proxy(proxy) .connectTimeout(Duration.ofSeconds(5)) .readTimeout(Duration.ofSeconds(30)) .build();
Create one Resend instance and reuse it: every service it returns shares the same HTTP client.
To take full control of the HTTP layer, pass your own IHttpClient with .httpClient(...). For example, to use
your own OkHttpClient (interceptors, TLS settings, a shared connection pool), add the
com.squareup.okhttp3:okhttp-jvm dependency to your build and wrap it in the built-in HttpClient:
import com.resend.Resend; import com.resend.core.net.impl.HttpClient; import okhttp3.OkHttpClient; // 1. Configure your OkHttpClient, e.g. with an interceptor that logs every request OkHttpClient okHttpClient = new OkHttpClient.Builder() .addInterceptor(chain -> { System.out.println(chain.request().method() + " " + chain.request().url()); return chain.proceed(chain.request()); }) .build(); // 2. Wrap it in the built-in HttpClient and build the client Resend resend = Resend.builder() .apiKey("re_123") .httpClient(new HttpClient(okHttpClient, "https://api.resend.com")) .build();
A custom httpClient can't be combined with baseUrl, the timeouts or proxy; configure those on your client.
You can view all the examples in the examples folder