Stack Overflow Acquisition, Valuation, Funding & Investors
Stack Overflow was acquired by Prosus for $1.8B in June 2021.
Cumulative funding Stack Overflow raised
$135M
across 3 funding rounds
Key investors in Stack Overflow
Andreessen Horowitz
Index Ventures
Spark Capital
Union Square Ventures
Bezos Expeditions
GIC
Silver Lake Waterman
Times Bridge
About Stack Overflow
Stack Overflow is a New York-headquartered Q&A platform where over 100 million monthly developers exchange code solutions, documentation, and career advice. It features tagged question threads, reputation scoring, and job boards alongside Stack Overflow for Teams for private enterprise knowledge bases. Launched in 2008, the site hosts 20 million questions across languages like Python, JavaScript, and Java, powering communities through API integrations for tools like GitHub and IDEs.
Founded
2008
HQ
New York City, NYWebsite
Status
Acquired
Customer focus
B2B & B2C
Revenue model
Advertising, Subscription
Valuation
$1.8B (acquired Jun 2021)
Stack Overflow Acquisition
Stack Overflow was acquired by Prosus for $1.8B on 2 June 2021.
Before the acquisition Stack Overflow had raised $135M across 3 funding rounds.
| Acquirer | Date | Type | Price |
|---|---|---|---|
| 2 Jun 2021 | Strategic M&A | $1.8B |
Stack Overflow Funding History
Stack Overflow has raised a total of $135M across 3 funding rounds.
Stack Overflow's first fundraising round was a $10M Series C in June 2013. The most recent completed round was a $85M Series E in July 2020.
Stack Overflow funding rounds
| Date | Stage | Investors | Raised | Deal Summary |
|---|---|---|---|---|
| Jul 2020 | Series E | GIC (lead); Index Ventures; Spark Capital; Union Square Ventures; Silver Lake Waterman; Andreessen Horowitz; Times Bridge | $85M | Stack Overflow, the leading Q&A platform for developers visited by over 120 million people monthly, raised $85 million in its Series E funding round on July 28, 2020, led by GIC with participation from Silver Lake Waterman and existing investors Andreessen Horowitz, Index Ventures, Spark Capital, and Union Square Ventures. This brought total funding to $153 million. The capital was earmarked to accelerate Stack Overflow for Teams, its SaaS knowledge management and collaboration product launched in 2017, which had seen revenue double annually. The round followed a five-year gap since the prior raise in 2015, positioning Stack Overflow to invest in public community tools, moderation, and developer products amid symbiotic growth between its free Q&A site and enterprise offerings. Stack Overflow for Teams targeted enterprise needs for internal knowledge sharing, leveraging the public platform's vast expertise. Investors like GIC, a Singapore sovereign wealth fund with tech experience, joined to support expansion into new markets and product enhancements. The company emphasized long-term mission alignment with technologists building future applications. |
| Jan 2015 | Series D | Andreessen Horowitz (lead); Index Ventures; Spark Capital; Union Square Ventures; Bezos Expeditions | $40M | Stack Overflow, operated by Stack Exchange (now known as Stack Overflow), is a leading Q&A platform for professional and enthusiast programmers founded in 2008. The company raised $40 million in a Series D funding round in January 2015, led by Andreessen Horowitz, with participation from existing investors including Union Square Ventures, Spark Capital, Bezos Expeditions, and Index Ventures. This brought the total funding raised to $70 million at that time. The investment aimed to enhance platform capabilities, support new product development, and capitalize on its role as a key resource for over 26 million developers, serving as a talent hunting ground for more than 10,000 companies including Amazon and Microsoft. Chris Dixon from Andreessen Horowitz joined the board as an observer, highlighting Stack Overflow's status as the indispensable home for the world's programmers due to its community-driven model that prioritizes high-quality answers through voting and avoids opinionated or commercialized content. CEO Joel Spolsky emphasized the platform's design to make programmers' jobs easier by surfacing the best answers first and maintaining trust through editorial independence. This round followed prior financings: Series A ($6M in May 2010 led by Union Square Ventures), Series B ($12M in March 2011 led by Index Ventures and Spark Capital), and Series C ($10M in June 2013 led by Bezos Expeditions). The platform's growth was driven by network effects and the established audiences of founders Joel Spolsky and Jeff Atwood, positioning it strongly in the developer community amid a shortage of programming talent. |
| Jun 2013 | Series C | Bezos Expeditions (lead) | $10M | Stack Overflow raised $10M in its Series C funding round in June 2013 led by Bezos Expeditions. The funding aimed to further develop the platform and expand its user base. Previous rounds included a $6M Series A in May 2010 led by Union Square Ventures and a $12M Series B in March 2011 led by Index Ventures and Spark Capital. |
Who has invested in Stack Overflow?
8 investors have backed Stack Overflow across its funding rounds, including Andreessen Horowitz, Index Ventures, Spark Capital, Union Square Ventures, Bezos Expeditions and GIC.
Lead investors include GIC, Andreessen Horowitz and Bezos Expeditions.
Stack Overflow Investors
| Investor | HQ | Rounds | Role | First check |
|---|---|---|---|---|
 London | 2 | Participant | Jan 2015 | |
| San Francisco, CA | 2 | Participant | Jan 2015 | |
| New York City, NY | 2 | Participant | Jan 2015 | |
| San Francisco, CA | 2 | Lead | Jan 2015 | |
| Washington, DC | 2 | Lead | Jun 2013 | |
 Singapore | 1 | Lead | Jul 2020 | |
This data is available for Pro users. Sign up to see all 8 Stack Overflow investors. Start Free Trial | ||||
Benchmark 350K+ Funding Rounds and Disclosed VC Valuation Multiples
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Start Free TrialInvestments by Stack Overflow
Stack Overflow has invested in 1 company to date.
Latest investment by Stack Overflow was on April 15th 2026. Stack Overflow invested in Flare in their $4M Pre-seed round.
Latest Investments by Stack Overflow
| Description | Flare is an infrastructure provider linking real-world data to machine learning through verifiable methods. The platform merges human intelligence and AI to enhance information clarity and reliability. Flare aims to build a shared knowledge base for confident information navigation. |
| HQ Country |  |
| HQ City | Copenhagen |
| Deal Date | 15 Apr 2026 |
| Round | Pre-seed |
| Raised | $4M |
| Investors | Eilert Giertsen Hanoa; Encord; HubSpot; 20Growth; Reddit; byFounders; Meta; 20VC; GitHub |
| Valuation | undisclosed |
| EV/Revenue | |
| EV/EBITDA | |
This data is available for Pro users. Sign up to see all Stack Overflow investments and their VC round multiples. Start Free Trial | |
Stack Overflow Competitors
Stack Overflow competitors include listed companies like Justsystems, C3.ai and Progress Software, and private ones like Bled Tech, CircleCI and LMArena.
| Company | HQ | Status | Revenue | EBITDA | Valuation | Revenue Multiple |
|---|---|---|---|---|---|---|
 Japan | Publicly listed | $331M | $156M | $1.8B | 3.2x | |
| United States | Publicly listed | $250M | ($484M) | $1.7B | 4.5x | |
| London | Private | $96M | - | $1.7B | 17.7x | |
| San Francisco, CA | Private | - | - | $1.7B | - | |
| San Francisco, CA | Private | $30M | - | $1.7B | 56.7x | |
| United States | Publicly listed | $978M | $302M | $1.7B | 2.9x |
Stack Overflow Public Comps
Stack Overflow is no longer listed, but its public comps include Justsystems, Sanoma, C3.ai, Visual China Group, Progress Software, Xinhuanet, Ziff Davis, TX Group, Webtoon and Alma Media.
| Last FY | EV/Revenue | EV/EBITDA | ||||||
|---|---|---|---|---|---|---|---|---|
| Revenue | EBITDA | Last FY | LTM | 2027E | Last FY | LTM | 2027E | |
| $331M | $156M | 3.1x | 3.2x | 6.7x | - | |||
| $1.5B | $293M | 1.2x | 1.2x | 6.4x | 4.2x | |||
| $250M | ($484M) | 4.3x | 4.5x | (2.2x) | (6.2x) | |||
| $116M | $21M | 13.9x | 14.6x | 75.6x | 38.9x | |||
| $978M | $302M | 3.0x | 2.9x | 9.6x | 7.3x | |||
| $333M | $66M | 4.9x | 5.0x | 24.8x | 26.9x | |||
| $1.5B | $335M | 0.9x | 1.0x | 3.8x | 3.3x | |||
| $1.1B | $310M | 2.1x | 2.1x | 7.2x | 8.1x | |||
This data is available for Pro users. Sign up to see all Stack Overflow competitors and their valuation data. Start Free Trial | ||||||||
Common questions about Stack Overflow
| When was Stack Overflow founded? | Stack Overflow was founded in 2008. |
| Where is Stack Overflow headquartered? | Stack Overflow is headquartered in New York City, NY, United States. |
| Is Stack Overflow publicly listed? | No, Stack Overflow was acquired by Prosus in June 2021. |
| Who acquired Stack Overflow? | Stack Overflow was acquired by Prosus in June 2021. |
| How much was Stack Overflow acquired for? | Stack Overflow was acquired for $1.8B in June 2021. |
| How much funding has Stack Overflow raised? | Stack Overflow has raised $135M across 3 funding rounds. |
| What was Stack Overflow's last funding round? | Stack Overflow's last funding round was a $85M Series E in July 2020, led by GIC. |
| Who are Stack Overflow's investors? | Stack Overflow's investors include Index Ventures, Spark Capital, Union Square Ventures, Andreessen Horowitz, Bezos Expeditions, GIC, Silver Lake Waterman and Times Bridge. |
| Which companies are comparable to Stack Overflow? | Companies comparable to Stack Overflow include Justsystems, C3.ai, Bled Tech, CircleCI, LMArena and Progress Software. |
| How many companies has Stack Overflow invested in? | Stack Overflow has invested in 1 company, including Flare. |
| What was Stack Overflow's last investment? | In April 2026, Stack Overflow invested in Flare's $4M pre-seed round alongside Eilert Giertsen Hanoa, Encord, HubSpot and 6 other investors. |
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