Which tools and technologies are used to build the Stack Exchange Network?

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What tools and technologies are used to build the Stack Exchange Network?

See also: Which tools and technologies are used to build Data Explorer?

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See also Does StackExchange 2.0 Share the Same CodeBase with SO? — Arjan, Commented Sep 2, 2010 at 23:48
See also: What technologies were used to build the chat? (though this currently has no real answers.) — Arjan, Commented Jan 15, 2011 at 19:12
See also Stack Exchange’s Architecture in Bullet Points on the blog. — Arjan, Commented Mar 4, 2011 at 21:35
See also Stack Exchange: Planning for failure and other posts on Nick's blog. — Arjan, Commented Apr 15, 2012 at 20:47
This is an implementation detail, you should only care about what's documented :P — nawfal, Commented Jul 22, 2014 at 12:16

98 revs, 51 users 21% unknown · Accepted Answer · 2023-09-29 22:23:01Z

Core

Stack Overflow uses a WISC stack ~~via BizSpark~~ (we graduated!):

Operating System Microsoft Windows Server 2019 x64
Web Server IIS 10
Database SQL Server 2019 running Microsoft Windows Server 2016 x64
Language C#

Software Development Tools

IDE Visual Studio 2019
Framework Microsoft .NET 6.0
Web Framework ASP.NET Core 6.0 with MiniProfiler
View Engine Razor
Browser Framework jQuery 1.12.4
Data Access Layer Entity Framework Core 2.2 and Dapper
Cache / Additional Data redis 4.0.7 via StackExchange.Redis, with serialization via protobuf-net
Source Control Git using a GitHub Enterprise instance hosted by GitHub (previously self-hosted GitHub, Mercurial from 2010–2014, Subversion from 2008–2010)
Compare Tool Beyond Compare 4

External Bits

Code used in Stack Overflow that is not included as part of the development tools:

reCAPTCHA
DotNetOpenAuth
WMD - Now developed as open source in the project PageDown
Highlight.js (was Prettify)
Google Analytics
TeamCity
HAProxy
MarkdownSharp
LESS (source)
MathJax
Elasticsearch (source)

Miscellaneous

WordPress on Linux (Site Blogs) Jekyll (on linux?) (for blog.stackexchange.com)
WebSocket (for real time updates; custom C# implementation)
Bandwidth used by Stack Exchange sites
jQuery Isotope plugin (for the grid-style site list) ^_(Source)

Content

License Creative Commons Attribution-Share Alike 4.0 for content contributed on or after 2018-05-02 (UTC); Creative Commons Attribution-Share Alike 3.0 for content contributed between 2011-04-08 and 2018-05-01 (UTC); Creative Commons Attribution-Share Alike 2.5 for content contributed before 2011-04-08 (UTC) (source)
Standards OpenSearch, Atom
Host two datacenters:
- New York: QTS (technically in Jersey City, NJ now). Formerly hosted at Internap and PEER 1.
- Denver: FORTRUST

Hardware

11 Dell R640 IIS web servers (9 shared for all production like SO, two for Meta and development):
- 2x Intel Xeon Processor Gold 6226 @ 2.7 GHz 12 Core with 24 threads
- 96 GB RAM
- Windows Server 2019
- Two drives
  - 2 Toshiba 480GB SAS SSD (RAID 1)
- 2x 10 Gbit/s NIC teaming

Three Dell R720xd database servers (two in New York City, one in Denver, using SQL AlwaysOn Clustering) (Global "Sites" DB & Stack Overflow dedicated):
- 2x Intel Xeon Processor E5-2680 @ 2.7 GHz
- 384 GB RAM
- 21 drives
  - Mirrored Pair for OS
  - 2 Intel P3700 2TB PCIe NVMe RAID1 for databases
  - 24 Intel 710 200GB SSD RAID10 for databases
- SQL Server 2014 SP1
- 2x 10 Gbit/s NIC teaming

Three Dell R730 database servers (two in New York City, one in Denver, using SQL AlwaysOn Clustering) (All other sites, Careers, Area 51, etc.):
- 2x Intel Xeon Processor X5680 @ 3.33 GHz
- 768 GB RAM
- 28 drives
  - Mirrored Pair for OS
  - 2 Intel P3700 2TB PCIe NVMe RAID0 for databases
  - 24 1.2TB 10K RAID10 for large databases
- SQL Server 2014 SP1
- 2x 10 Gbit/s NIC teaming

Two Dell R640 HAProxy servers (direct):
- 2x Intel Xeon Gold 5218 @ 2.3 GHz
- 96 GB RAM
- CentOS 7
- 2x 10 Gbit/s NIC teaming (internal)
- 2x 10 Gbit/s NIC teaming (external)

Two Dell R640 HAProxy servers (CloudFlare):
- 2x Intel Xeon Gold 5218 @ 2.3 GHz
- 96 GB RAM
- CentOS 7
- 2x 10 Gbit/s NIC teaming (internal)
- 2x 10 Gbit/s NIC teaming (external)

2 Dell R640 Redis servers:
- 2x Intel Xeon Gold 6244 @ 3.6 GHz
- 384 GB RAM
- CentOS 7
- 2x 10 Gbit/s NIC teaming

Three Dell R640 Service servers for tag engine/search:
- 2x Intel Xeon Gold 6244 @ 3.6 GHz
- 96 GB RAM

One Dell R620 Backup server running NetBackup (most backups):
- 2x Intel Xeon Processor E52620 @ 2.0 GHz
- 16 GB RAM
- 14 drives
  - Mirrored Pair for OS
  - 12 4TB 10K RPM RAID10 for backups (DAS)
- 2x 10 Gbit/s NIC teaming

One Dell R730xd SMB3 Backup server (SQL backups):
- 2x Intel Xeon Processor E5-2623v3 @ 3.0 GHz
- 16 GB RAM
- 30 drives
  - Mirrored Pair for OS
  - 16 6TB 7.2K RPM RAID10 for backups (Internal)
  - 12 4TB 10K RPM RAID10 for backups (DAS)
- 2x 10 Gbit/s NIC teaming

Six Dell R640 VMWare ESX servers:
- 2x Intel Xeon Gold 6240 @ 2.60 GHz
- 1.5 TB RAM
- 16x 10 Gbit/s NIC teaming (8x 10 Gbit/s per FX2s)

2 Cisco ASR1001-X routers
2 ASR1001 Routers
2 Fortinet 1100E Firewalls
2 Cisco Nexus 5596 Cores in an active/active redundant configuration

Sources:

Hmmm, the list seems incomplete. I don't see Unicornify in there... — Lunatik, Commented May 6, 2010 at 7:10
I love how people are so into bc3 that they it is listed as part of the stack — user145917, Commented Sep 20, 2010 at 12:35
Can I ask how on earth the SO team managed to update the site to user Razor so quickly? Did they actually port older aspx views into razor or are legacy pages running with razor side-by-side? — gideon, Commented Apr 2, 2011 at 9:50
What is the platform/code that the blog is run on? I've posted a question on this already. — casperOne, Commented Jun 6, 2011 at 0:14
Probably should include this one as well meta.stackexchange.com/questions/216324/… — Templar, Commented Jul 3, 2014 at 18:00
I see VMWare in there somewhere, but could you please elaborate which systems are Bare Metal and which are running under virtualization, perhaps Hyper-V? — Jason Caldwell, Commented Jul 23, 2014 at 0:11
I have to say I was surprised to see this level of technical detail made public. I'm not sure how common this is, but my gut tells me that security pedants wouldn't be overjoyed by it. That is, purely theoretically, a malicious party might be able to narrow the space of attack options based on the level of details here. Just my two cents. — sammy34, Commented May 30, 2015 at 14:48
"Microsoft Windows Server 2017 x64" - What? Did MS release a special version of Windows Server between 2016 and 2019 exclusively for Stack's use? — jmbpiano, Commented Apr 18, 2019 at 15:36
This answer needs two updates: 1. We're switching to CommonMark, but they still use MarkdownSharp and PageDown to some extent for special features; don’t know how much into detail this post should go. 2. An Update On Creative Commons Licensing; they don’t use CC BY-SA 4.0 for all the content. They use 2.5, 3.0, and 4.0. — Sebastian Simon, Commented Jun 25, 2020 at 2:02
What is used on the front-end? Only jQuery? Also, why such an old version of jQuery? — IvanD, Commented Dec 28, 2020 at 0:16
@sammy34 probably you should stop storing your credit card info in your stackexchange profile, then. — Him, Commented Dec 6, 2022 at 20:08

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Which tools and technologies are used to build the Stack Exchange Network?

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