# Stack Overflow: The Architecture - 2016 Edition

DevFeed: [Stack Overflow: The Architecture - 2016 Edition](<https://devfeed.tech/articles/stack-overflow-the-architecture-2016-edition-21590.md>)

Original publisher: [Read original article](<https://nickcraver.com/blog/2016/02/17/stack-overflow-the-architecture-2016-edition/>)

Published: 2016-02-17T00:00:00Z

Content type: article

Language: en

Sources: [Nick Craver](<https://devfeed.tech/sources/nick-craver.md>)

Topics: [Stack Overflow](<https://devfeed.tech/topics/stackoverflow.md>), [ASP.NET](<https://devfeed.tech/topics/aspnet.md>), [Redis](<https://devfeed.tech/topics/redis.md>), [SQL](<https://devfeed.tech/topics/sql.md>), [Hardware](<https://devfeed.tech/topics/hardware.md>), [servers](<https://devfeed.tech/topics/servers.md>), [elasticsearch](<https://devfeed.tech/topics/elasticsearch.md>), [Server](<https://devfeed.tech/topics/server.md>)

Tags: [architecture](<https://devfeed.tech/tags/architecture.md>), [asp-net](<https://devfeed.tech/tags/asp-net.md>), [blog](<https://devfeed.tech/tags/blog.md>), [cloudflare](<https://devfeed.tech/tags/cloudflare.md>), [elasticsearch](<https://devfeed.tech/tags/elasticsearch.md>), [hardware](<https://devfeed.tech/tags/hardware.md>), [http](<https://devfeed.tech/tags/http.md>), [load-balancer](<https://devfeed.tech/tags/load-balancer.md>), [performance](<https://devfeed.tech/tags/performance.md>), [redis](<https://devfeed.tech/tags/redis.md>), [servers](<https://devfeed.tech/tags/servers.md>), [sql](<https://devfeed.tech/tags/sql.md>)

## AI overview

This article describes Stack Overflow's 2016 architecture using daily traffic and performance statistics from February 9, 2016, compared with November 2013. It covers HTTP requests, page loads, SQL queries, Redis hits, Elasticsearch searches, Tag Engine requests, and processing times. The author attributes reduced ASP.NET processing time to a 2015 hardware upgrade and application performance tuning, then lists the main server and load-balancer hardware.

## Source excerpt

This is #1 in a very long series of posts on Stack Overflow's architecture. Welcome. Previous post (#0): Stack Overflow: A Technical Deconstruction Next post (#2): Stack Overflow: The Hardware - 2016 Edition To get an idea of what all of this stuff "does," let me start off with an update on the average day at Stack Overflow. So you can compare to the previous numbers from November 2013, here's a day of statistics from February 9th, 2016 with differences since November 12th, 2013: 209,420,973 (+61,336,090) HTTP requests to our load balancer 66,294,789 (+30,199,477) of those were page loads 1,240,266,346,053 (+406,273,363,426) bytes (1.24 TB) of HTTP traffic sent 569,449,470,023 (+282,874,825,991) bytes (569 GB) total received 3,084,303,599,266 (+1,958,311,041,954) bytes (3.08 TB) total sent 504,816,843 (+170,244,740) SQL Queries (from HTTP requests alone) 5,831,683,114 (+5,418,818,063) Redis hits 17,158,874 (not tracked in 2013) Elastic searches 3,661,134 (+57,716) Tag Engine requests 607,073,066 (+48,848,481) ms (168 hours) spent running SQL queries 10,396,073 (-88,950,843) ms (2.8 hours) spent on Redis hits 147,018,571 (+14,634,512) ms (40.8 hours) spent on Tag Engine requests 1,609,944,301 (-1,118,232,744) ms (447 hours) spent processing in ASP.Net 22.71 (-5.29) ms average (19.12 ms in ASP.Net) for 49,180,275 question page renders 11.80 (-53.2) ms average (8.81 ms in ASP.Net) for 6,370,076 home page renders You may be wondering about the drastic ASP.Net reduction in processing time compared to 2013 (which was 757 hours) despite 61 million more requests a day. That's due to both a hardware upgrade in early 2015 as well as a lot of performance tuning inside the applications themselves. Please don't forget: performance is still a feature. If you're curious about more hardware specifics than I'm about to provide--fear not. The next post will be an appendix with detailed hardware specs for all of the servers that run the sites (I'll update this with a link when it's liv