REST vs Streaming Forex APIs

Choosing between a REST endpoint and a streaming socket shapes how a trading application consumes market data, how much bandwidth it burns, and whether it ever misses a price peak.

Live-Rates offers both, and each answers a different engineering need. This guide breaks down where each format shines, where it falls short, and which developers should reach for which.

Key takeaways

• Live-Rates has shipped a REST API since early 2019 and added a Streaming API to most subscription plans afterward.
• REST is a simple HTTP GET that works with virtually any technology stack.
• REST is capped at one request per second while rates can update up to three times per second, so peaks can be missed.
• The Streaming API uses a single long-lived socket.io connection, saving bandwidth and delivering every update.
• REST suits easy integrations; streaming suits latency-sensitive apps that cannot afford to lose a PIP.

Two APIs, One Data Feed

Live-Rates provides two types of APIs that share the same purpose: delivering real-time, low-latency financial data to developers across forex, commodities, indexes, and more.

By early 2019, the only available output was the REST API. Since then, the offer has been extended to also include the Streaming API in most subscription plans.

REST API

The REST API is very easy to use. Its implementation is always just an HTTP GET request, and it can be used with virtually any technology stack that uses the Internet.

Trade-offs

A new request has to be made every time the user wants or needs to fetch new data, which causes extra bandwidth usage. Because only one request can be made per second while data can be updated up to three times per second, some data may be lost between requests.

Who it fits

The REST API is recommended for users who are looking for an easy implementation and who can accept losing occasional price peaks.

Streaming API

The Streaming API is built with socket.io and can be accessed through the Node.js or PHP libraries.

Why it is efficient

Only a single long-lasting connection is established with the server, and prices are then sent automatically. This saves many resources and bandwidth. Because the server always pushes updated data to the client, there is no risk of losing currency peaks between requests.

Who it fits

The Streaming API is recommended for advanced users who are looking for efficiency in their applications or solutions and cannot lose a single PIP.

Choosing Between the Two

The decision comes down to implementation effort versus data completeness. Teams that need a quick integration and can tolerate gaps should start with REST; teams building latency-sensitive tools where every tick matters should opt for the Streaming API.

FAQ

When did Live-Rates launch each API?

The REST API was the only output available by early 2019. The Streaming API was added later and is now included in most subscription plans.

How often can data be fetched over REST?

Only one REST request can be made per second, while the underlying data can update up to three times per second, so some updates can be missed between calls.

What technology powers the Streaming API?

The Streaming API is built with socket.io and can be consumed through the official Node.js or PHP example libraries on GitHub.

Why does streaming save bandwidth?

Streaming opens a single long-lasting connection to the server, which then pushes updated prices automatically instead of requiring a fresh HTTP request for each fetch.

Which API is right for latency-sensitive apps?

The Streaming API is recommended for advanced users who need efficiency and cannot afford to lose a single PIP, since it never drops updates between requests.

Ready to plug real-time forex data into an application? Compare tiers and pick the right fit on the Live-Rates plans page.