fast

Rarely in software does anyone ask for “fast.” We ask for features, we ask for volume discounts, we ask for the next data integration. We never think to ask for fast.

But software that's fast changes behavior.

Developers ship more often when code deploys in seconds (or milliseconds) instead of minutes.

AI code complete means we can prototype in languages we're less familiar with.

Real-time streaming makes remote work possible.

Conversely, slow software limits us more than we realize. When was the last time you used airplane WiFi and actually got a lot done? Maybe you sent a few Slack messages or answered a couple emails. Google Docs worked half of the time. You probably gave up. Instagram usually works pretty well—Facebook knows how important it is to be fast.

Fast is magical.

Fast eliminates cognitive friction. Raycast surfacing the right application before you finish typing feels like an extension of your mind. Superhuman's sub-100ms rule—plus their focus on keyboard shortcuts—changed the email game in a way that no one's been able to replicate, let alone beat. I recently used Mercury to pay another business that uses Mercury, and its instant settle felt surprising in a world where bank transfers usually take days.

No one praises these tools explicitly for their speed. They just feel magical.

Fast signals simplicity, which is even rarer in a world where code and content are commodities.

Fast software has nowhere to hide. Network calls and dependencies reveal themselves through latency, and this brutal honesty forces discipline. Companies that do fast very well tend to have very focused products.

This is because the effort to make software fast often requires stripping away non-essential features. Compare how fast a streamlined project management tool like Linear loads versus an enterprise app like Workday (or worse… Oracle). In a world obsessed with adding rather than refining, speed becomes the ultimate expression of respect. It says, "We've thought deeply about what matters and eliminated everything else."

In order to make things fast, you often have to do complex things behind the scenes. At Cash App, we were very careful to only introduce additional steps in the user's journey when it was absolutely needed, which meant we had to handle a lot of messiness in the background. In this interview, Kevin Systrom explains how Instagram optimistically uploaded users' photos while they entered their caption to make the upload experience feel instant. Fast isn't just a technical accomplishment—it signals prioritization and focus.

Fast is fun

Also, we like fast because it's fun! We count WPM typing speeds for very little benefit except that it's fun to be faster than other people. The first thing we do on a new computer is set-up our hotkeys so we can go at the same speed as our last set-up.

Fast is relative

A lot of LLM-augmented workflows are infinitely faster than their pre-LLM counterparts today. Asking an LLM to research for 6 minutes is already 10000x faster than asking for a report that used to take days.

And yet, it's obvious to anyone that writes code that we're very far from the standards that we're used to from the previous software era. We're very focused on capabilities, and we're not very focused on performance or experience. We accept the clunkiness because the magic is still new, and that's ok! It's all still way faster than a human. But the current tools we have to build, run, and deploy AI apps feel very far off from the developer experience that we'll have in the future. We haven't yet begun the phase where optimization becomes the priority.

When we do, you'll see more and more companies optimizing for low latency, interface design, connectivity, and reliability. This, in turn, will unlock new capabilities and use cases that we aren't yet even thinking about. After all, the best software changes the way we live our lives, and we build our lives around software that feels like superpowers.

==

Some other pieces about fast that I've liked: Patrick Collison, Charlie Marsh, Paul Graham.

april 9, 2025
← back