MongoNetworkError: self signed certificate in certificate chain

I try to connect to a managed MongoDB from an Express/NodeJS component hosted in Digital Ocean apps. The MongoDB database is added as component to the app. This created a DATABASE_URL env variable and I’m using that.

But my express app crashes with MongoServerSelectionError: self signed certificate in certificate chain

What could cause that? I can connect from MongoDB compass, but that is a different connection string. (with certificate)

Submit an answer
Answer a question...

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Greg M
DigitalOcean Employee
DigitalOcean Employee badge
December 16, 2021
Accepted Answer

Hello, have you tried using the certificate that is provided by the bound environment variable?


And use the ssl cert provided by ${<db-name>.CA_CERT} (mapping to whatever env name you would like when you connect, making sure to specify the sslCA:

Thanks, not sure if this is the best way, but this works:

let mongoCertPath = path.resolve("./ca-certificate.crt");
if (process.env.CA_CERT) {
  fs.writeFileSync(mongoCertPath, process.env.CA_CERT);

let client = new MongoClient(process.env.DATABASE_URL, {
  sslCA: mongoCertPath,
let clientPromise = client.connect();

Want to learn more? Join the DigitalOcean Community!

Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in Q&A, subscribe to topics of interest, and get courses and tools that will help you grow as a developer and scale your project or business.