As with everything, choosing solutions is a matter of dealing with trade-offs. The ones that adapt best to the projects and applications we’re writing are what we end up using. Deno has some limitations, some due to its short lifetime and others due to design decisions. As it happens with most solutions, Deno is also not a one-size-fits-all tool. Let’s explore some of the current limitations of Deno and the motivations behind them.

Not as stable as Node.js

In its current state, Deno can’t be compared to Node.js regarding stability for obvious reasons. Node.js has more than 10 years of development, while Deno is only nearing its second year.

Even though most of the core features presented in this course are already considered stable and correctly versioned, there are still features that are subject to change and live under the unstable flag.

Node.js’s years of experience ensure it’s battle tested and works in the most diversified environments. We’re hopeful Deno will get that, but time and adoption are essential factors.

Better HTTP latency but worse throughput

Deno keeps performance on track from the beginning. However, as seen on the benchmarks page, there are topics where it’s still not at Node.js’s level.

Its ancestor leverages the direct bindings with C++ on the HTTP server to amplify this performance score. Since Deno resisted adding native HTTP bindings and builds on top of native TCP sockets, it still suffers from a performance penalty. This decision is something that the team plans to tackle after optimizing TCP socket communication.

The Deno HTTP server handles about 25,000 requests per second with a max latencyThe delay caused before a data transfer begins following an instruction for its transfer. of 1.3 milliseconds, while Node.js handles 34,000 requests but has a latency that varies between 2 and 300 milliseconds.

We can’t say 25,000 requests per second is not enough, especially since we’re using JavaScript. If our app/website needs more than that, probably JavaScript, and thus Deno, is not the correct tool for the job.

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