[throwaway50603]

Isn't it more expensive to have many people poll frequently?

[breput]

The entire public sec.gov site, including filing data, is served from the Akamai CDN.

But there is also an AUP (https://www.sec.gov/os/accessing-edgar-data) which limits the number of requests per second, which in reality is quite a bit less than is documented.

[TylerE]

Vs push where someone sets up to receive it and then… never turns it off?

[gadflyinyoureye]

Might not. Caching plus nginx would allow pretty decent performance. Not sure how expensive misses would be.