You don't want to expose the IP address of your back-end/data server to the internet, unless you are very good with security. If you're not the best with security, you will get hacked very soon!
So, you can put your back-end server behind a proxy. That does add a bit of latency to each request. However, by using one of the below "API Gateways" you can also get some additional benefits besides just hiding your IP.
Authenticate and connect to 3rd party services on the back-end instead of on the front-end. Accept and return data in the same format. This is an important abstraction - if you want to change to a different 3rd party web service later, you can continue to return the data in the same format as before. No need to constantly refactor your front-end whenever the data changes.
Google Endpoints
Easy to set up. Google even has a database migration tool. https://cloud.google.com/endpoints/docs/openapi
Microsoft Azure
AWS API Gateway
AWS has many powerful and advanced products for web development, like Route 53. They are the leader. https://aws.amazon.com/api-gateway/
Fusio
Simplifies the entire process. Open-source. API management, Developer signup/authentication, Documentation, Monetization, Authorization and rate limiting. It even automatically generates a CRUD API from a database table! fusio-project.org/#features
KrakenD
Supposed to be super fast and powerful. Idk. I wish they usd the OpenAPI format though instead of proprietary config files. https://www.krakend.io/docs/configuration/structure/
Gloo
They seem to have many features, but I don't understand what is unique just by reading the site. https://www.solo.io/products/gloo-edge/
Vercel, Netlify, Amplify API
For front-end and full-stack developers, some excellent options are popping up that let you easily and quickly create a backend API to use with your front-end app.
They do limit how much compute time your API endpoints can use. No web scraping or data mining with this back-end, but they give you plenty of time to make requests to 3rd party APIs to fetch and send data back and forth around the internet.
This is perfect for front-end apps. You don't want to manage many different connections and authentications (with security keys and such) on the front-end. So, offload that sensitive work to your own back-end which you, the front-end developer, control. Return data from multiple 3rd party APIs in a standard format for your front-end app.
Feather
It's a self-hosted API server, but same concept. Not sure how production-ready it is, but it's great for prototyping and development. Like Fusio, it can automatically convert a database table to a CRUD API. Empowers you to convert 3rd party APIs and micro services into GraphQL format, so your front-end can be efficient and consistent.
CloudFlare
Globally-distributed network of back-end servers and databases with no effort! Pretty amazing. It's not a true API Gateway, but more a system for reading/writing data to a database, which may be enough for most people.
Unfortunately CloudFlare API endpoints time out after just 50 milliseconds. This is not for doing any HTTP requests to 3rd party servers.
It's the best option however, if all you need is to read/write data quickly to your own NoSQL table, from anywhere in the world. Everything fully managed by CloudFlare and works like magic.
RapidAPI
This is the one and only marketplace for APIs. No programming. Just sign up on their site and you're all set. Connect your API to their marketplace, and use them as a proxy server to protect your own server from hackers. They let you easily authenticate and monetize your APIs, which is amazing!
Kong and Apigee
The enterprise solutions for what RapidAPI is doing. Manage all your APIs and microservices, authenticate, monetize. Expensive. For enterprise businesses.
Great Alternative to RapidAPI
https://app.nocodeapi.com/marketplace - Sign up with NoCodeAPI.com. Use many different APIs without having to manage so many different accounts. Great idea! Great execution!