Author
Chen Yu
Technical Engineer
Author · 20 articles · 35 glossary terms
Focuses on tracking code, SDKs, and API integrations, with practical guidance on implementation checks and troubleshooting.
Articles by Chen Yu
20 articles
Analytics · Nov 6, 2026 · 5 min read
App versioning: best practices and how to compare releases
App versioning explained: version vs build number, semantic versioning for apps, nine best practices, what to compare per release and a staged rollout example.
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Analytics · Nov 6, 2026 · 6 min read
Implementing web analytics: an 8-step plan and checklist
How to implement web analytics properly: questions, tracking plan, installation, events and goals, data hygiene, privacy and verification against your backend, with a worked example.
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Analytics · Nov 6, 2026 · 7 min read
How to improve app performance: metrics, targets and 8 fixes
Improve mobile app performance with the metrics that matter (cold start, jank, ANR, crashes, memory, network), official thresholds, eight steps and a worked example that halved cold start.
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Growth & Marketing · Nov 6, 2026 · 7 min read
Mobile app optimization: stability, onboarding, conversion and store
Mobile app optimization across four areas: stability and performance, onboarding and engagement, conversion and store visibility. A seven-step process, a version comparison example and common mistakes.
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Product News · Nov 6, 2026 · 5 min read
App engagement metrics: formulas, benchmarks by app type and a worked case
The app engagement metrics that matter, with formulas: DAU, MAU, stickiness, session length and interval, engaged sessions and retention. How to judge them by app type, and a worked case where opens rose 22% but real use barely moved.
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Analytics · Nov 6, 2026 · 6 min read
Web performance monitoring: RUM vs synthetic, metrics and a worked regression
How to monitor website performance continuously: real user monitoring vs synthetic checks, Core Web Vitals at P75, and a worked release where mobile LCP jumped from 2.3 to 3.5 seconds and add-to-cart fell.
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Analytics · Nov 5, 2026 · 6 min read
ETL vs ELT: differences, a worked example and how to choose
ETL transforms data before loading; ELT loads raw data and transforms it in the warehouse. A comparison table, a worked example of restating a metric after its definition changes, the privacy catch, EtLT, reverse ETL and a decision checklist.
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Analytics · Nov 5, 2026 · 6 min read
What is a data pipeline? Stages, types and an analytics example
A data pipeline moves data from where it is created to where it is used. The six stages and how each one fails, batch vs streaming, ETL vs ELT, and a worked event-pipeline example with duplicates, late data and the monitors that catch them.
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Analytics · Nov 4, 2026 · 4 min read
Data Taxonomy for Analytics: Naming Rules and a Cleanup Example
A data taxonomy is the agreed structure and naming of your events, properties and values, so everyone counts the same thing the same way. The four layers, naming rules with examples, a worked cleanup from 186 event names to 42, and how to keep it from drifting.
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Analytics · Nov 4, 2026 · 4 min read
What Is a Good Page Load Time? A Clear Target and How to Check It
A good page load time is when the main content appears within 2.5 seconds for three in four real visits. Why full load time misleads, targets for each timing, and a sample split by device and page type.
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Analytics · Nov 4, 2026 · 4 min read
Data Sampling in Analytics: When It Is Fine and When It Misleads
Data sampling means reading a subset to estimate the whole. The main sampling methods, where analytics tools sample, how small segments and rare events go wrong, and rules for trusting sampled numbers.
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Analytics · Nov 4, 2026 · 4 min read
Website Performance Metrics: The Five to Watch and How to Read Them
The website performance metrics that matter: LCP, INP, CLS, FCP and TTFB, their thresholds, why to read the 75th percentile from real users, and a sample that traces a slow page to its cause.
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Analytics · Nov 4, 2026 · 6 min read
What Is Data Quality? The Six Dimensions, Applied to Analytics Data
Data quality is how far data can be trusted for the decision you want to make. The six dimensions (accuracy, completeness, consistency, timeliness, validity and uniqueness) with the analytics failure each one catches and a weekly check list.
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AI Search · Nov 3, 2026 · 5 min read
Log File Analysis for SEO: A Tool-Neutral Method in Six Questions
Server logs show what search engine crawlers actually request, not what a crawl tool assumes. How to get the logs, verify that Googlebot is real, and answer six questions that turn raw lines into SEO fixes.
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Analytics · Nov 3, 2026 · 6 min read
Real User Monitoring: How to Read Speed Data from Real Visits
Real user monitoring (RUM) measures speed in visitors' own browsers. How it differs from synthetic tests, why P75 by device is the default view, how small samples mislead, and how to turn a slow segment into a fix.
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Analytics · Nov 3, 2026 · 6 min read
Server-Side Tracking: What to Send from the Server, and What Not
What server-side tracking is good for and what it is not, how to split events between browser and server, and how to keep sessions and attribution connected without double counting.
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Analytics · Nov 3, 2026 · 7 min read
Event Tracking: How to Set It Up in 5 Steps
Event tracking records the actions a pageview misses: sign-ups, clicks, purchases. A five-step setup with a starter event plan, naming rules, code, automatic events and a verification checklist.
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AI Search · Sep 17, 2026 · 8 min read
llms.txt: what to write, an example, and how to check whether anyone reads it
What llms.txt is and is not, the structure the proposal defines, a real example, how it should agree with robots.txt, and how to check in your server logs whether AI agents fetch it.
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Product News · Aug 13, 2026 · 8 min read
Event naming conventions: rules, mistakes, and how the event inbox drafts names
A practical event naming convention (object_action, snake_case, past tense), the mistakes that break it, and how TapCub’s event inbox turns autocaptured clicks into named events you accept, merge or ignore.
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AI Search · Mar 26, 2026 · 9 min read
How to block AI crawlers: user agents, robots.txt rules and how to check them
GPTBot, ClaudeBot, Google-Extended and the rest do different jobs. Which AI crawlers to block, the robots.txt rules to use, what to enforce at the server, and how to check it worked.
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Glossary terms by Chen Yu
35 glossary terms
Glossary
95th percentile (P95)
A percentile is the value below which a given share of measurements falls.
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Glossary
AI crawler
A bot operated by an AI company to collect training data or answer queries in real time, such as fetchers behind chat assistants and search answers.
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Glossary
Autocapture
Recording clicks, form submits and page changes automatically, without writing tracking code for each one.
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Glossary
Beta testing
Beta testing is the stage where a nearly finished product or feature is released to a limited group of real users outside the development team, to find bugs, usability problems and missing pieces in real conditions before the general release.
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Glossary
Cardinality in data: what it is and why high cardinality matters
Cardinality is the number of distinct elements in a set.
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Glossary
Cumulative Layout Shift (CLS)
Cumulative Layout Shift (CLS) is a Core Web Vital that scores how much visible content moves unexpectedly while a page is open.
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Glossary
Customer data platform (CDP)
A customer data platform (CDP) is software that collects first-party customer data from many sources, merges it into a persistent profile for each person, and makes those profiles and audiences available to other systems such as email, ads and support tools.
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Glossary
Data dictionary
A data dictionary is a reference document or table that lists every field in a dataset or system and records, for each one, its name, plain-language meaning, data type, allowed values, source and owner.
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Glossary
Data latency
Data latency is the time between an event happening, such as a page view or purchase, and that event being available to query or see in a report.
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Glossary
Data layer
In web analytics, a data layer is a JavaScript object or array on the page, such as window.
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Glossary
Data lineage: what it is, why it matters and a worked example
Data lineage is the documented path of data from its sources through every transformation to the reports and systems that use it, at table, column or business-metric level, used for root-cause analysis, impact analysis, audit and compliance.
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Glossary
Data observability
Data observability is the practice of continuously measuring the health of data, such as its freshness, volume, schema, value distribution and lineage, so that problems are detected early and traced to the step where they started.
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Glossary
Device ID: types, how analytics uses it and privacy rules
A device ID is an identifier used to recognize a specific device over time.
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Glossary
DOMContentLoaded: what it is, vs load, and what delays it
DOMContentLoaded is a browser event fired when the initial HTML document has been fully parsed and deferred scripts have executed, without waiting for images, iframes and other subresources, which complete at the later load event.
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Glossary
Event / property
An event is something that happened — "added to cart"; a property is a detail attached to it — product, price, currency.
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Glossary
First Contentful Paint (FCP)
First Contentful Paint (FCP) measures the time from the start of navigation until the browser renders the first piece of content from the page: text, an image, a non-white canvas or an SVG.
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Glossary
First input delay (FID): what it measured and why INP replaced it
First input delay (FID) measured the time from a user’s first interaction with a page to when the browser could begin processing event handlers for it.
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Glossary
HAR file: what it is, what is inside and how to read it
A HAR (HTTP Archive) file is a JSON log of the network requests a browser made while loading a page, including URLs, headers, cookies, bodies, status codes and per-request timings.
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Glossary
identify / identity resolution
The call that tells TapCub "this visitor is user 4821", and the rules that merge the anonymous visits before sign-in with the identified ones after.
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Glossary
Identity resolution
Identity resolution is the process of recognising that different identifiers, such as anonymous visitor ids, device ids, login ids and email addresses, belong to the same person, and linking them into one profile.
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Glossary
Interaction to Next Paint (INP)
Interaction to Next Paint (INP) is a Core Web Vital that measures responsiveness: the time from a click, tap or key press until the browser paints the next frame, taken from close to the slowest interaction of the visit.
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Glossary
Largest Contentful Paint (LCP)
Largest Contentful Paint (LCP) is a Core Web Vital that measures the time from when a page starts loading until the largest image, video poster or text block in the viewport has rendered.
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Glossary
Mobile app analytics
Mobile app analytics is the collection and analysis of data about how people use a mobile app (starts, screens, events, retention, purchases) and how stable and fast it is, usually gathered by an SDK inside the app.
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Glossary
Monitor / alert
A rule that watches a metric and notifies you when it crosses a threshold or deviates from its usual pattern — conversions down 30% against the same hour last week, for example.
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Glossary
Native app
A native app is a mobile application built for one specific operating system using its own languages, SDKs and UI components (Swift for iOS, Kotlin for Android), installed from an app store with full access to device features.
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Glossary
SDK
An SDK (software development kit) is a package of libraries, documentation, sample code and tools that lets developers add a platform’s or service’s capability to their own software, often by wrapping that service’s API.
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Glossary
Speed Index: what it measures, how it is calculated and how to improve it
Speed Index is a lab performance metric that measures how quickly the visible content of a page is displayed during load, computed as the area above the visual-completeness curve of a recorded page load.
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Glossary
Synthetic monitoring: what it is and how it differs from RUM
Synthetic monitoring tests websites, apps and APIs by running scripted requests or browser journeys from controlled locations on a schedule, detecting outages and performance regressions before or without real user traffic.
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Glossary
Tech stack
A tech stack (technology stack) is the combination of programming languages, frameworks, databases, infrastructure and third-party tools that a team uses to build, run and measure a software product.
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Glossary
Time to First Byte (TTFB)
Time to first byte (TTFB) is the time from the start of navigation until the first byte of the page’s response arrives.
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Glossary
Total blocking time (TBT): formula, example and how to reduce it
Total blocking time (TBT) is a lab metric that sums, for every main-thread task longer than 50 ms between first contentful paint and Time to Interactive, the time beyond 50 ms.
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Glossary
Unique visitor
The number of distinct people in a period.
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Glossary
User ID
A user ID is a stable, unique identifier your product assigns to a signed-in person and sends to analytics, so their activity on every device and in every session counts as one user.
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Glossary
UUID
A UUID (universally unique identifier) is a 128-bit value, usually written as 36 characters like 3f2b8c1e-7d4a-4f6b-9a21-5c0e8d7b1f42, that can be generated independently on any machine with a negligible chance of two ever being the same.
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Glossary
Web Vitals
Google's page-experience metrics: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, Cumulative Layout Shift for visual stability.
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