Response compression: the questions we get asked most

This is cheap to get right at the start and expensive to retrofit. The questions about response compression that come up most often on our calls.

Performance work is mostly subtraction, which makes it unpopular and effective. If it only works because one person remembers to do something, it does not work yet.

Do we need to care about this?

Text compresses dramatically and costs almost nothing to enable. Where this goes wrong is almost never a lack of knowledge. The version that survives contact with a real deadline is the simple one.

Can it wait until after launch?

Occasionally. More often the post-launch version costs several times the pre-launch one. It is worth being explicit about, because assumptions differ quietly.

How do we know it is working?

Already-compressed formats gain nothing from it. Getting it slightly wrong is survivable. Ignoring it entirely is not. Budget a little time for it every quarter and it never becomes a project of its own.

The short version

Real-world numbers from actual visitors matter more than a score produced on a fast laptop. Three things worth confirming about response compression before you move on:

• Someone can say what the current setup is without going to look
• Modern algorithms beat older ones by a useful margin — and you know whether that is true here
• There is a way to tell whether the last change to this helped

If you are not sure where your systems currently stand on this, it takes us about an hour to find out.