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

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();

Try DigitalOcean for free

Click below to sign up and get $200 of credit to try our products over 60 days!

Sign up

Featured on Community

Get our biweekly newsletter

Sign up for Infrastructure as a Newsletter.

Hollie's Hub for Good

Working on improving health and education, reducing inequality, and spurring economic growth? We'd like to help.

Become a contributor

Get paid to write technical tutorials and select a tech-focused charity to receive a matching donation.

Welcome to the developer cloud

DigitalOcean makes it simple to launch in the cloud and scale up as you grow — whether you're running one virtual machine or ten thousand.

Learn more
DigitalOcean Cloud Control Panel