The archive · Developer & Business Tools · Product decision · 2022
Clockwork raised $21M for nanosecond server time sync; launched Latency Sensei
Stanford spinout Clockwork sells nanosecond-accurate server time sync and a latency product built on it; NEA led its $21M Series A in March 2022.
Clockwork
What the business is
Clockwork sells nanosecond-grade time synchronization for servers plus Latency Sensei, a product that uses trusted clocks to deliver fine-grained latency data across cloud, on-premises and hybrid environments.
Starting capital：US$21M Series A (2022-03-16) led by NEA, with angel investors John Hennessy, Ram Shriram and Jerry Yang participating.
How it started
The idea grew out of Stanford research by Mendel Rosenblum and Balaji Prabhakar's teams into what distributed systems could do if clocks were trustworthy. Prabhakar described servers inside data centers that could not agree even on the second, while NTP-based sync stays far from microsecond accuracy. Yilong Geng, Deepak Merugu and Prabhakar founded Clockwork, with Rosenblum as chief scientist, and built a system that measures timestamp arrival times, feeds clock offset and frequency drift into a machine learning model, and lets clocks detect and correct each other.
What happened
On 2022-03-16 Clockwork announced a $21M Series A led by NEA, joined by angels John Hennessy, Ram Shriram and Jerry Yang, and launched its first product, Latency Sensei, claiming sync accuracy down to 5 nanoseconds with hardware timestamps and hundreds of nanoseconds with software timestamps. Customers already included Nasdaq, Wells Fargo and RBC. The roadmap pointed to congestion detection that would give TCP better routing hints inside data centers, and the founders argued trustworthy time could reopen time-based algorithms for database consistency, event ordering, consensus and ledgers.
No ending yet — it is still running.
Background
Clockwork is a Stanford-linked startup selling nanosecond-grade time synchronization for data centers and, on top of it, Latency Sensei, a product for fine-grained latency visibility across cloud, on-premises and hybrid environments. On 2022-03-16 it announced a $21M Series A led by NEA and launched Latency Sensei, with Nasdaq, Wells Fargo and RBC already named as customers.
The bet was that unreliable clocks are the reason distributed systems avoid time, and that making clocks nanosecond-true would change how those systems are built. Founders Yilong Geng, Deepak Merugu and Balaji Prabhakar, with Mendel Rosenblum as chief scientist, built a system that measures timestamp arrival times and feeds clock offset and frequency drift into a machine learning model, claiming accuracy down to 5 nanoseconds with hardware timestamps.
The product logic was that accurate one-way latency measurement is impossible without trusted clocks, so Latency Sensei could see what round-trip estimates miss. The Hacker News discussion on 2022-03-17 (122 points, 124 comments) mixed technical skepticism with pointers to the underlying NSDI papers; a Clockwork team member answered in-thread and pointed to public cloud fitness reports on AWS, GCP and Azure, with congestion control promised next.
What has to be true
- The team had unusual depth: the founders and chief scientist were Stanford researchers whose clock-synchronization and congestion-control work had been published before the company existed.
- The wedge was defensible: correcting ordinary servers with software plus ML avoids the cost of high-accuracy clocks that would exceed the price of the server itself.
- Latency products give a paying wedge for the research: finance customers such as Nasdaq, Wells Fargo and RBC need precise timestamps and one-way latency measurements.
- The company bet that 'nobody uses time except Spanner and CockroachDB' would not stay true, opening consensus, event ordering and ledger algorithms to everyone.
What can be applied
A deep research insight becomes a company only through a product: Clockwork's first offer was Latency Sensei, with named finance customers, not another paper.
Aftermath
As of the 2022-03-17 snapshot, Clockwork had just announced its Series A and first product: Latency Sensei was in beta, its team was answering questions on Hacker News, and edge-based congestion control was described as coming soon. The sources reviewed here do not cover what happened to the company after that week, so this entry stops at the announcement.
Sources
- Clockwork raises $21M to keep server clocks in sync
- Clockwork raises $21M to keep server clocks in sync (Hacker News discussion)
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