Arista Networks vs. Datadog: Which Technology Stock Is a Better Buy in 2026?

As artificial intelligence and cloud migration continue to reshape the corporate landscape, investors often find themselves choosing between hardware and software champions. Which of these high-growth leaders, Arista Networks (NYSE:ANET) or Datadog (NASDAQ:DDOG), is the better buy today?

Arista Networks provides the physical switches and software that allow data to move quickly through massive cloud data centers. Datadog offers a software-as-a-service platform that helps companies monitor the health and security of those same cloud environments. Both companies are essential players in the modern digital economy, though they occupy different parts of the infrastructure stack.

The case for Arista Networks

Arista Networks is a leader among tech stocks that power the physical backbone of the internet. The company designs data-driven networking platforms for cloud titans, financial services firms, and specialty AI providers. Because a limited number of large customers account for a significant portion of revenue, this customer concentration adds a layer of risk to the business.

In FY 2025, revenue reached nearly $9.0 billion, which represents growth of approximately 28.6% over the previous year. Net income for the same period was close to $3.5 billion. This resulted in a net margin of roughly 39%, which is the percentage of total revenue remaining as profit after all operating and non-operating expenses are paid.

As of its December 2025 balance sheet, Arista Networks reported a debt-to-equity ratio of 0.0x, meaning it carries virtually no debt relative to the value owned by shareholders. The current ratio of 3.0x suggests the company has three times more short-term assets than liabilities, which measures its ability to cover immediate financial obligations. Free cash flow, the cash remaining after capital expenditures, was approximately $4.3 billion in FY 2025.

The case for Datadog

Datadog provides an AI-powered observability and security platform that brings infrastructure, applications, and data into a single view. The company serves approximately 32,700 customers globally, ranging from high-growth start-ups to large enterprise organizations. Its software helps engineering and security teams manage complex cloud environments, ensuring that applications remain stable and secure as they scale.

In FY 2025, revenue reached nearly $3.4 billion, reflecting growth of approximately 27.7% compared to the prior year. Net income for this period was close to $107.7 million. The company reported a net margin of roughly 3.1%, indicating the portion of total revenue converted into profit after accounting for all costs of doing business.

As of its December 2025 balance sheet, Datadog maintained a debt-to-equity ratio of 0.4x. This ratio compares a company's total debt to the value owned by its shareholders. The current ratio of 3.4x indicates a strong ability to meet short-term liabilities. Free cash flow for FY 2025 was close to $1.0 billion. Note that stock-based compensation represented roughly 71.5% of operating cash flow, which inflates reported cash generation since SBC is a non-cash expense added back in the cash flow statement.

Risk profile comparison

Arista Networks faces significant risks related to its reliance on a small number of massive cloud customers for a large portion of its sales. The company is also dependent on Broadcom (NASDAQ:AVGO) for critical silicon components, creating a potential supply chain bottleneck. Furthermore, international trade tensions and export controls regarding AI technologies could impact its ability to sell in certain global markets.

Datadog operates in a highly competitive market where it must outpace both home-grown solutions and diversified giants like Microsoft (NASDAQ:MSFT) and Cisco Systems (NASDAQ:CSCO). The company is also dependent on third-party cloud infrastructure providers to host its own services, which could lead to increased costs or service interruptions. Rapid growth also presents organizational challenges in maintaining its engineering culture and meeting complex data privacy regulations across 160 countries.

Valuation comparison

Arista Networks appears more attractive on a price-to-earnings basis, while both companies trade at similar multiples relative to their trailing revenue.

Valuation metrics include sourcing from Financial Modeling Prep (FMP) and may differ from other data providers.

The Forward P/E, which compares the stock price to future earnings estimates, suggests investors are paying a much higher premium for Datadog's expected profits. The P/S ratio, which measures market capitalization relative to sales over the past twelve months, reflects a valuation closer to parity between the hardware and software providers.

Which stock would I buy in 2026?

If I had to own just one of these for the next decade, I'd probably lose sleep over choosing the better of the two. But I'd go with Arista Networks.

Arista just crossed $3 billion in quarterly revenue for the first time in Q2 2026, growing more than 40% year over year. Every major AI data center being built needs high-speed networking, and Arista keeps winning that business. The margins are exceptional and the balance sheet is clean.

I'm a fan of Datadog too. Quarter after quarter, the company is beating earnings estimates by wide margins, and Q2 2026 was no exception. Revenue grew at a strong double-digit rate, and free cash flow is building steadily. AI is driving customers to monitor more infrastructure, not less, which keeps expanding Datadog's addressable market.

The honest reason I'd pick Arista is infrastructure. You cannot run AI at scale without the networking, and Arista is the company most enterprises are turning to for that. Investors will get a fresh update when both companies report Q3 2026 results in early November.

Sara Appino has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Arista Networks, Broadcom, Cisco Systems, Datadog, and Microsoft. The Motley Fool has a disclosure policy.