Amplitude

What Is Amplitude?

Amplitude is a digital-analytics and product-analytics platform built to help product and growth teams understand user behavior at scale and connect that behavior to business outcomes. Like its main rival Mixpanel, Amplitude is organized around events rather than page views, but it is especially known for behavioral cohorting, user-journey analysis, and tying product usage to retention and revenue. It is one of the most widely adopted product-analytics tools among technology companies and has positioned itself as a broad "digital analytics platform" rather than a narrow event tracker.

Founded in 2012, Amplitude grew up alongside the modern SaaS and mobile-app era, where the questions that matter are behavioral: which actions predict that a user will stick around, which features drive expansion, and how different cohorts move through a product over time. For anyone auditing a web or mobile application's measurement stack, Amplitude is a strong signal that the team is investing in behavioral, retention-focused analysis rather than only marketing metrics.

This profile explains how Amplitude works, the concrete technical signals that reveal it on a live site, its key capabilities, its trade-offs, and how it compares to alternatives such as Mixpanel and Google Analytics 4.

How Amplitude Works

Amplitude captures data through a browser JavaScript SDK and parallel SDKs for iOS, Android, and server environments. The browser library has historically been delivered from cdn.amplitude.com, under paths like cdn.amplitude.com/libs/amplitude-*.js (and, for the newer Browser SDK 2.0, from cdn.amplitude.com/script/<api-key>.js). Once loaded, it exposes a global amplitude object that developers call to log activity.

The core method is amplitude.track('Event Name', { property: value }) (older SDK versions used logEvent). Each call records an event with properties; the SDK batches events and sends them to Amplitude's ingestion endpoint, typically api2.amplitude.com or a regional host such as api.eu.amplitude.com. Identity is managed with setUserId() and an automatically generated device ID, while user properties are attached with an Identify API. The SDK also persists state in first-party cookies prefixed AMP_ (modern SDKs) or amplitude_* (older versions) so it can stitch sessions together.

What distinguishes Amplitude is the analysis layer on top of this event stream. Behavioral cohorts let you define groups based on what users have or have not done, and those cohorts become reusable building blocks across charts and even syncable audiences. Pathfinder and journey tools reveal the sequences users actually follow, and impact-style analyses estimate how a given behavior relates to retention or conversion. Amplitude stores events in an analytics backend optimized for fast, interactive querying across very large datasets, which is what makes exploratory behavioral analysis practical.

Amplitude also supports server-side ingestion, data exports to warehouses, and ingestion from customer-data platforms, so a site might send Amplitude data from the browser, the backend, or routed through a CDP like Segment.

A concept worth understanding when reading an Amplitude implementation is the relationship between device ID, user ID, and Amplitude ID. The device ID is generated automatically and identifies a browser or app instance; the user ID is set by the application once a person is known; and Amplitude resolves these into a canonical Amplitude ID that represents the underlying user across devices. This resolution is what lets Amplitude follow a person who starts on mobile and continues on desktop. Sessions are also handled automatically: the SDK starts a new session after a period of inactivity and can fire session-start and session-end events, which feed engagement and frequency metrics. Newer Browser SDK 2.0 deployments add optional autocapture for page views, clicks, and form interactions, reducing the amount of manual instrumentation required. Recognizing whether a site uses autocapture or hand-coded track calls can tell you a lot about how mature and deliberate its analytics practice is.

How to Tell if a Website Uses Amplitude

Amplitude has clear, recognizable fingerprints. Here are the most reliable signals and the tools to find them.

Script domains and file names. The strongest tell is a script request to cdn.amplitude.com, for example cdn.amplitude.com/libs/amplitude-8.x.x-min.gz.js or the newer cdn.amplitude.com/script/<key>.js. Some sites proxy or self-host the SDK, but the Amplitude CDN domain is the clearest signal.

JavaScript globals. In DevTools open the Console, type amplitude, and press Enter. If Amplitude is loaded you will get an object with methods such as track/logEvent, setUserId, and getInstance. Checking window.amplitude confirms the global is defined.

Network requests. In the DevTools Network tab, reload and filter for amplitude. Watch for ingestion beacons to api2.amplitude.com, api.amplitude.com, or a regional endpoint like api.eu.amplitude.com. These requests carry the batched event payloads.

Cookies. Modern Amplitude SDKs set first-party cookies prefixed AMP_ (for example AMP_<hash>), while older versions used names like amplitude_id_<key>. In DevTools open Application, then Cookies, and look for those prefixes.

Detection at a glance:

Tool	What to look for	Signal of Amplitude
View Source	cdn.amplitude.com/libs/amplitude-* or /script/<key>.js	SDK loaded in HTML
DevTools Console	Type amplitude, then amplitude.getInstance()	Global object defined
DevTools Network	Requests to api*.amplitude.com	Events being sent
DevTools Application	Cookies starting with AMP_ (or amplitude_id_*)	First-party Amplitude state
curl -I / curl	curl -s https://example.com | grep -i amplitude	SDK reference in raw HTML
Wappalyzer	Extension flags "Amplitude"	Automated detection
BuiltWith	Analytics section lists Amplitude	Historical and current detection

A quick curl -s https://example.com piped to a search for amplitude confirms whether the SDK is referenced in the server-rendered markup. As with other event trackers, Amplitude is often loaded by a tag manager or routed through a CDP such as Segment, in which case the raw HTML will not mention it and the runtime request to api*.amplitude.com becomes the reliable confirmation. To check many URLs at once, StackOptic runs these server-side detections for you. For a complete methodology, read our guide on how to find out what analytics a website uses and the broader piece on how to find out what technology a website uses.

Key Features

• Event-based behavioral analytics. Track user actions with rich properties as the foundation for every report.
• Behavioral cohorts. Define groups by what users did or did not do, then reuse those cohorts across analyses and sync them to other tools.
• Funnel analysis. Measure conversion through defined steps, including time-to-convert and segment-level drop-off.
• Retention analysis. Visualize return rates over custom windows to gauge stickiness and the impact of changes.
• User journeys and Pathfinder. Discover the real sequences users follow without predefining paths.
• Dashboards and notebooks. Combine charts into shareable dashboards and analytical narratives.
• Experimentation. Amplitude Experiment integrates A/B testing with the same behavioral data, so results are analyzed in full context.
• Warehouse-native and data pipelines. Export raw events, or run analyses on data in your warehouse.

Pros and Cons

Pros

• Deep behavioral analysis with powerful cohorting and journey tools.
• Fast, interactive exploration across large event datasets.
• Integrated experimentation ties product changes directly to behavioral outcomes.
• Generous free tier and a broad platform vision spanning analytics, experimentation, and audiences.
• Strong fit for cross-platform (web plus mobile) behavioral measurement.

Cons

• Requires a thoughtful tracking plan; weak event design undermines trust in the data.
• More complex to implement and learn than drop-in page-view analytics.
• Less emphasis on marketing-channel and advertising reporting than Google Analytics.
• Costs scale with event volume and can rise quickly at high traffic.
• Data is vendor-hosted, which may not satisfy strict data-ownership or residency needs.

Amplitude vs Alternatives

Amplitude's most direct competitor is Mixpanel; the two share an event-and-property model and overlap heavily in funnels and retention. The broader contrast is with general web analytics like Google Analytics 4 and with customer-data platforms like Segment that feed analytics tools rather than replace them.

Platform	Primary focus	Data model	Strength	Best for
Amplitude	Product/behavioral analytics	Events + properties	Behavioral cohorts, journeys, experimentation	Growth teams doing deep behavioral analysis
Mixpanel	Product analytics	Events + properties	Funnels, retention, fast querying	Product teams optimizing engagement
Google Analytics 4	Web + app analytics	Events (free)	Acquisition, ads, BigQuery export	Marketing-led teams in the Google ecosystem
Segment	Customer data platform	Events routed to tools	One integration, many destinations	Teams sending one event stream everywhere

Versus Mixpanel, the choice often comes down to nuance: Amplitude is celebrated for behavioral cohorting and a broad platform vision, while Mixpanel is praised for approachability and query speed. Versus Google Analytics 4, Amplitude is more specialized for in-product behavior and retention, and less oriented toward marketing-channel and ad reporting. It is common for teams to use a CDP to route the same events to Amplitude and GA4 simultaneously.

Common Use Cases

• Retention and stickiness analysis. Identify which behaviors predict long-term retention and double down on them.
• Activation funnels. Pinpoint where new users drop off before reaching value and fix those steps.
• Feature impact measurement. Quantify how feature usage relates to retention, conversion, or expansion.
• Growth experimentation. Run A/B tests with Amplitude Experiment and analyze them against behavioral cohorts.
• Cross-platform product insight. Unify web and mobile behavior to understand the full customer journey.

Frequently Asked Questions

Is Amplitude better than Mixpanel?

Neither is universally "better"; they are close competitors with similar event models. Amplitude is often favored for deep behavioral cohorting and its broader platform (analytics plus experimentation and audiences), while Mixpanel is frequently praised for an approachable interface and fast queries. The right choice depends on your team's workflows, budget, and which interface analysts prefer.

How can I tell if a website uses Amplitude?

Look for a script from cdn.amplitude.com, the global amplitude object in the DevTools Console, network requests to api2.amplitude.com or a regional endpoint, and first-party cookies prefixed AMP_. If Amplitude is loaded via a tag manager or a CDP, View Source may not reveal it, so confirm with the DevTools Network tab.

What cookies does Amplitude set?

Modern Amplitude SDKs set first-party cookies prefixed AMP_ (such as AMP_<hash>) to persist device and session identifiers, while older SDK versions used names like amplitude_id_<api-key>. These cookies let Amplitude stitch a visitor's events together across page loads. You can inspect them under Application, then Cookies, in DevTools.

Is Amplitude free to use?

Amplitude offers a free starter plan with a monthly event allowance suitable for small products and early evaluation. Beyond that, paid plans scale with tracked events and unlock more features, history, and governance. Because pricing is event-based, high-traffic applications should estimate monthly event volume before adopting it broadly.

Does Amplitude track personal data?

Amplitude records events and the properties you choose to send, plus a device or user identifier used to stitch sessions. Whether that includes personal data depends entirely on what your implementation sends and how you configure user IDs and properties. Amplitude provides controls for data governance, but compliant use is the responsibility of the team deploying it.

Why might Amplitude requests go to api.eu.amplitude.com instead of api2.amplitude.com?

Amplitude offers regional data residency, and a site configured for the EU data center will send ingestion beacons to api.eu.amplitude.com rather than the default api2.amplitude.com. Seeing the EU endpoint in the DevTools Network tab is a useful signal that the organization has chosen European data storage, often for GDPR or data-residency reasons. The same fingerprints (the cdn.amplitude.com script and AMP_ cookies) still apply regardless of region.

What is the difference between Amplitude Analytics and Amplitude Experiment?

Amplitude Analytics is the core product for understanding behavior through events, funnels, retention, and cohorts. Amplitude Experiment is the feature-flagging and A/B testing layer that sits on top of the same data, letting teams roll out changes to specific cohorts and measure their impact using the identical behavioral metrics. Because both share one data foundation, an experiment's results can be analyzed with full behavioral context rather than in an isolated testing tool, which is a key reason teams adopt the combined platform.