React-native fetch() from https server with self-signed certificate

Disclaimer: This solution should be temporary and documented so that it won't stay in the production phase of the software, this is for development only.

For iOS, all you have to do is, open your xcodeproject (inside your iOS folder in RN) once you have that open, go to RCTNetwork.xcodeproj and in that project, navigate to RCTHTTPRequestHandler.m

In that file you will see a line like this:

#pragma mark - NSURLSession delegate

right after that line, add this function

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler
{
  completionHandler(NSURLSessionAuthChallengeUseCredential, [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust]);
}

And voila, you can now make insecure calls to your API without a valid certificate.

That should be enough, but if you are still having problems, you might need to go to your project's info.plist, left click on it and choose open as... source code.

and at the end just add

<key>NSAppTransportSecurity</key>
  <dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
  </dict>
  <key>NSExceptionDomains</key>
    <dict>
        <key>localhost</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
        <key>subdomain.example.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
    </dict>

so your file will look like this

    ...
    <key>UISupportedInterfaceOrientations</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>UIViewControllerBasedStatusBarAppearance</key>
    <false/>
    <key>NSLocationWhenInUseUsageDescription</key>
    <string></string>
  <key>NSAppTransportSecurity</key>
  <dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
  </dict>
  <key>NSExceptionDomains</key>
    <dict>
        <key>localhost</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
        <key>subdomain.example.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
    </dict>
</dict>
</plist>

For a real production ready solution, https://stackoverflow.com/a/36368360/5943130 that solution is better

I am also faced the same issue in android. Finally i found the solution for this issue.

import com.facebook.react.modules.network.OkHttpClientFactory;
import com.facebook.react.modules.network.OkHttpClientFactory;
import com.facebook.react.modules.network.OkHttpClientProvider;
import com.facebook.react.modules.network.ReactCookieJarContainer;

import java.security.cert.CertificateException;
import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.TimeUnit;


import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

import okhttp3.CipherSuite;
import okhttp3.ConnectionSpec;
import okhttp3.OkHttpClient;
import okhttp3.TlsVersion;

import static android.content.ContentValues.TAG;

public class CustomClientFactory implements OkHttpClientFactory {
    private static final String TAG = "OkHttpClientFactory";
    @Override
    public OkHttpClient createNewNetworkModuleClient() {
        try {
            // Create a trust manager that does not validate certificate chains
            final TrustManager[] trustAllCerts = new TrustManager[]{
                    new X509TrustManager() {
                        @Override
                        public void checkClientTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                        }

                        @Override
                        public void checkServerTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                        }

                        @Override
                        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                            return new java.security.cert.X509Certificate[]{};
                        }
                    }
            };

            // Install the all-trusting trust manager
            final SSLContext sslContext = SSLContext.getInstance("SSL");
            sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
            // Create an ssl socket factory with our all-trusting manager
            final SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();



            OkHttpClient.Builder builder = new OkHttpClient.Builder()
                    .connectTimeout(0, TimeUnit.MILLISECONDS).readTimeout(0, TimeUnit.MILLISECONDS)
                    .writeTimeout(0, TimeUnit.MILLISECONDS).cookieJar(new ReactCookieJarContainer());
            builder.sslSocketFactory(sslSocketFactory, (X509TrustManager) trustAllCerts[0]);
            builder.hostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });

            OkHttpClient okHttpClient = builder.build();
            return okHttpClient;
        } catch (Exception e) {
            Log.e(TAG, e.getMessage());
            throw new RuntimeException(e);
        }
    }

}

and inside our Android application MainApplication.java

 @Override
  public void onCreate() {
    super.onCreate();
    SoLoader.init(this, /* native exopackage */ false);  
    OkHttpClientProvider.setOkHttpClientFactory(new CustomClientFactory()); //add this line.
  }  

Its work for me. May be it will help to all.