PostHog launched on Hacker News four weeks after opening its repository
The PostHog/posthog repository was created on 23 January 2020, while its founders were in Y Combinator's Winter 2020 batch. In February they posted a Launch HN: "we are building a self-hosted, open source Mixpanel/Amplitude style product."
The repository gained 1,012 new stars that month. Only four months since have brought more.
The seed came the next month: $3 million in March 2020, from Y Combinator and 1984 Ventures. A $9 million Series A led by GV followed in July. PostHog announced both together in December 2020, alongside plugins, session recordings and feature flags. In June 2021 it announced a $15 million Series B led by Y Combinator's Continuity Fund.
The README went from one analytics product to a platform for agents
Each year the README's opening line described a wider product. The 2020 line named one product for developers. By 2023 it described an all-in-one platform, and in 2026 a layer of data that people and their agents query.
| End of | Opening line of the README |
|---|---|
| 2020 | "Open-source product analytics, built for developers" |
| 2021 | "An open-source product analytics suite, built for engineers" |
| 2022 | "An open-source suite of product and data tools, built for engineers" |
| 2023 | "An all-in-one, open source platform for building better products" |
| 2025 | "An all-in-one, open source platform for building successful products" |
| 2026 | "Your product's context layer" |
The 2026 README goes on: PostHog "ingests and stores your analytics, errors, replays, and business data so you and your agents can query and act on it."
New stars held level while more people opened pull requests
PostHog's new stars per year rose from 4,581 in 2022 to 7,771 in 2024, then stopped rising. 2025 brought 7,753, and its second half brought 3,211 against 4,542 in the first.
The work on the repository kept rising. In the busiest month of 2024, 53 people opened or merged pull requests. In the busiest month of 2025 it was 116, and in August 2026 it was 224. Commits on the default branch went from 5,415 in 2024 to 12,231 in 2025.
| People on pull requests | 2020: 20 | 2021: 27 | 2022: 31 | 2023: 42 | 2024: 53 | 2025: 116 | 2026: 224 |
|---|
Accounts, excluding bots, that opened or merged a pull request on PostHog/posthog in the busiest month of each year: 53 in 2024, 116 in 2025 and 224 in 2026.
| Year | New stars | Commits on the default branch | People on pull requests, busiest month |
|---|---|---|---|
| 2020 | 3,309 | 2,425 | 20 |
| 2021 | 1,906 | 4,140 | 27 |
| 2022 | 4,581 | 3,671 | 31 |
| 2023 | 4,682 | 4,455 | 42 |
| 2024 | 7,771 | 5,415 | 53 |
| 2025 | 7,753 | 12,231 | 116 |
| 2026 to Oct 20 | 10,359 | 36,705 | 224 |
The two largest rounds came after PostHog turned cashflow positive
PostHog's handbook records that the company became cashflow positive in December 2024. Its next three rounds came in 2025.
In June it announced a $70 million Series D at a $920 million valuation, led by Stripe, together with a smaller Series C of about $10 million. Co-founder James Hawkins wrote that one reason for the Series C was to let early employees sell some of their shares. In September it announced a $75 million Series E at $1.4 billion, led by Peak XV Partners.
The announcement months brought 726 new stars in June and 656 in September, against that year's monthly average of 646.
| Announced | Round | Amount | Led by | Valuation |
|---|---|---|---|---|
| Mar 2020 (closed) | Seed | $3M | Y Combinator, 1984 Ventures | Not disclosed |
| Dec 2020 | Series A | $9M | GV | Not disclosed |
| Jun 2021 | Series B | $15M | Y Combinator's Continuity Fund | Not disclosed |
| Jun 2025 | Series C | ~$10M | No lead named | Not disclosed |
| Jun 2025 | Series D | $70M | Stripe | $920M |
| Sep 2025 | Series E | $75M | Peak XV Partners | $1.4B |
The seed date is from PostHog's press page. The Series A closed in July 2020 and was announced in December.
In 2026, pull request counts stopped measuring people
On 15 September 2025, 71 pull requests were opened on the repository, all but one from a person's account. On 15 September 2026, 643 were.
368 of those 643 came from bot accounts. 225 were test pull requests opened by Trunk's merge queue, and none of them were merged. People's accounts opened the other 275, and 213 of those were merged, more than three times the 63 merged a year earlier. 23 of them came from branches named for coding agents, such as codex/ and claude/.
The same year the stars came back. April 2026 brought 1,919, and July and August brought 2,283 and 2,150, the repository's three best months. During 2026 PostHog wrote in March that agents had become a primary persona for its products, put PostHog Code, a desktop app that runs coding agents on product data, into beta in May, and wrote in July about its context warehouse for agents.
For PostHog, the people on the repository said more than its stars
PostHog's stars told the early story: a launch that brought a thousand of them in its first month, and a seed the month after. They did not tell the 2025 one. The year it raised its two largest rounds, new stars matched the year before and slowed in the second half.
What rose was the number of people opening and merging pull requests: 53 in the busiest month of 2024, 116 in the busiest month of 2025. We found the same gap in Chroma's GitHub history and Supabase's: stars count the accounts that starred the repository, not the people using the product.
How we measured this
- Commits and README text come from the repository itself on GitHub: commit counts on the default branch per calendar year, and the README as it stood at the end of each year.
- Stars come from GitHub's star history for the repository, counted by the day each star was given, from January 2020 to 20 October 2026. It counts the stars the repository has today, so a star that was later removed is not counted.
- People on pull requests is the number of distinct accounts, excluding bots, that opened or merged a pull request in a month, from GitHub's pull request records. It is not a count of employees or of everyone who contributed code.
- Pull requests on a single day were read from GitHub's pull request records for 15 September 2025 and 2026, with the account type, branch name and merge state of each.
- Funding comes from PostHog's own announcements and press page, linked where each is mentioned.
The README history and commit counts were produced by Vela's repository briefs, which read a public repository's history and cite each claim to the record it came from.
Frequently Asked Questions
When was the PostHog GitHub repository created?
The PostHog/posthog repository was created on 23 January 2020. PostHog launched on Hacker News in February 2020, during Y Combinator's Winter 2020 batch.
How much funding has PostHog raised?
PostHog has announced six rounds: a $3 million seed and a $9 million Series A in 2020, a $15 million Series B in 2021, and in 2025 a Series C of about $10 million, a $70 million Series D led by Stripe at a $920 million valuation and a $75 million Series E led by Peak XV Partners at $1.4 billion.
How did PostHog describe itself on GitHub?
In 2020 the README described open-source product analytics built for developers. By 2023 it described an all-in-one, open source platform for building better products. In 2026 it describes PostHog as your product's context layer, for people and their agents.
Did GitHub stars track PostHog's growth?
They tracked the 2020 launch, with 1,012 new stars in February 2020. They did not track 2025: new stars were 7,753, against 7,771 in 2024, while the number of people opening or merging pull requests in the busiest month went from 53 to 116.