Fastest Growing Startups in 2026: Who Leads and Why
The fastest growing startups depend on the yardstick. Revenue lists name Mercor, Ramp and ElevenLabs, while valuation and search lists name others. Here's how each list is built and which figures deserve trust.
What counts as one of the fastest growing startups?
No official ranking exists. A startup is a young, usually venture-backed private company.
"Fastest growing" is whatever the publisher chooses to measure. That makes any list of fastest growing startups a statement about method first and companies second.
The three pages we read use three different yardsticks:
Revenue growth: Darkroom Agency (9 September 2026) ranks companies using only figures they published themselves.
Valuation and age: HubSpot's 2025 Hypergrowth Startup Index counts the top 100 private, investment-backed companies founded within three years and valued above $100M.
Search growth: Shakuro (26 June 2023) measured how fast searches for each brand rose.
Readers often assume these lists rank the same thing. They don't, which is why the fastest growing startups on one list can be missing from another.
Which startups lead on reported revenue growth in 2026?
Darkroom's September 2026 article names five of the fastest growing startups by revenue. Its figures come from the companies themselves, and Darkroom admits that private numbers are hard to verify.
Company | Reported figure | Source and date |
Lovable | Reportedly $200M ARR by November 2025, as reported by Fortune | Darkroom, 9 Sep 2026 |
Mercor | $500M run-rate in 17 months; over $1B annualized in early 2026 | Darkroom, 9 Sep 2026 |
Sierra | $100M ARR in seven quarters, $200M in nine | Darkroom, 9 Sep 2026 |
ElevenLabs | $350M ARR at end of 2025; over $500M within four months of 2026 | Darkroom, 9 Sep 2026 |
Ramp | Over $1B annualized revenue, positive free cash flow, June 2026 | Darkroom, 9 Sep 2026 |
ARR means annual recurring revenue, the yearly value of repeating contracts. A run-rate takes a recent period and multiplies it up to a year, so it can look larger than what was actually billed.
Growth numbers for the fastest growing startups often surface around fundraising news, so they tend to be flattering snapshots rather than audited results. Treat each one as a claim with a date.
Ramp, for example, reached a $32 billion valuation on a $300 million round led by Lightspeed in November 2025, as reported by Bloomberg.
What does the HubSpot index say about fastest growing startups?
HubSpot's report defines fastest growing startups as the top 100 private, investment-backed companies founded in the past three years and valued above $100M. A unicorn, in its wording, is a private company valued above $1B.
Perplexity, founded in 2022 with under 200 employees, reportedly reached a valuation near $10B after a $500M round led by IVP.
Reuters reported on 6 November 2024, citing an unnamed source, a round of about $500M at about $9B, with no company confirmation in that report. HubSpot's near-$10B figure differs, and we couldn't confirm why.
AI, machine learning and software companies dominate the high-growth group.
Singapore, the UK, India and France are named as emerging growth hubs.
Investor Mark Roberge of Stage 2 Capital is quoted: "We really like vertical software plays that are very capital efficient."
How old is the data behind the HubSpot index?
The page shows no publication date. The data came from PitchBook in February 2025, with expert interviews in February and March 2025. By November 2026 that's about 21 months old, which is a long time for companies growing this quickly.
Valuation lists of fastest growing startups also tend to freeze a single funding round. A company can be marked up or down soon after the snapshot.
Why are search-growth lists of fastest growing startups weak evidence?
Shakuro's 2023 piece ranked eight of the fastest growing startups by growth in search interest. It is the oldest of the three pages, and it measures attention, not money.
Company | Search growth (Shakuro, 2023) | Founded |
Linktree | 2150% | 2016 |
Qerko | 1700% | 2017 |
Preply | 1466% | 2012 |
Cradlewise | 1328% | 2018 |
Tailwind | 1037% | 2015 |
Oura | 900% | 2013 |
StackBlitz | 822% | 2016 |
Labster | 555% | 2012 |
Shakuro doesn't say how the percentages were calculated. Several firms were founded over a decade before the article, which sits oddly with a "fastest growing startups" label.
Percentages from a small starting point also look huge. A pattern readers often notice is that the biggest percentage rarely belongs to the biggest business.
How can you check a growth claim yourself?
Before trusting any list of fastest growing startups, ask five questions of each figure.
What exactly is measured: revenue, valuation, users or searches?
Who published the number, the company or an outside party?
What date does it carry?
What was the starting size?
Is the term defined, such as ARR versus run-rate?
For deeper context on how funding feeds these numbers, our startup funding statistics and trends page is a useful companion.
Does the list of fastest growing startups show speed or size?
Speed is a rate. Size is a total. Mercor's growth to a $500M run-rate in 17 months is a speed claim, while Ramp's $1B annualized revenue is a size claim with a speed story attached. A list of the fastest growing startups should lead with speed, yet many lead with size.
A short comparison of the three yardsticks shows where each breaks down.
Yardstick | What it shows | Main weakness |
Revenue growth | Money coming in | Mostly company-reported, unaudited |
Valuation and age | Investor belief | A snapshot of one funding round |
Search growth | Public attention | Small bases inflate percentages |
Darkroom also sells marketing services and ends its piece with a promotion, so its advice is worth weighing with that in mind.
What do the fastest growing startups have in common?
Darkroom points to repeated habits among the fastest growing startups it covers:
Products that market themselves: Lovable users publish projects that act as free demos.
Expansion inside existing accounts, as with Ramp.
Outcome-based pricing: Sierra charges per resolved customer issue rather than per seat.
Developer integrations through an API, which Darkroom credits for ElevenLabs.
Putting effort into one channel at a time.
HubSpot's report adds that investors now favor fewer, larger rounds and lean companies that reach product-market fit fast. In practice, founders often report that these patterns look obvious only after growth has happened, so copying them is harder than listing them.
For a regional angle, see our guide to fast-growing startups in India.
How should you read fastest growing startups lists from different years?
Read the date first. The three pages we read span more than three years, from Shakuro in June 2023 to Darkroom in September 2026.
A 2023 list of fastest growing startups can't tell you who is growing fastest in late 2026.
HubSpot's February 2025 data sits in the middle, and its page is undated.
Only Darkroom's piece is recent, and it covers five companies.
A common pattern is that old lists keep circulating with a new year in the title. Check the original publication date, not the headline year, before using any figure.
What to do next
Pick the yardstick before you read any fastest growing startups list, then check each figure's source and date. Compare two lists on one metric, such as annualized revenue, and note where they disagree before you rely on either.
Frequently asked questions
What are the fastest growing startups in 2026?
By reported revenue, Darkroom's September 2026 article names Lovable, Mercor, Sierra, ElevenLabs and Ramp. Most figures are company-reported and unaudited, so they're claims, not a verified ranking.
How are the fastest growing startups measured?
There's no standard. Publishers use revenue growth, valuation reached quickly, or search growth. Always check which yardstick a list uses and the date of its figures.
Is a unicorn the same as one of the fastest growing startups?
No. HubSpot defines a unicorn as a private company valued above $1B. Some take many years to get there, so a unicorn label says nothing about speed.
Why do lists of the fastest growing startups disagree?
They measure different things and use different dates. One list may rank revenue, another valuation, another searches, so overlap is small by design.
Can search growth show the fastest growing startups?
Only as a rough sign of attention. Search growth isn't revenue, and small starting points inflate percentages, so it shouldn't be used alone.