Ruankao E-Commerce Designer (Intermediate) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

GMV

Gross Merchandise Value: the total value of goods transacted on a platform before deductions. It measures marketplace scale, not revenue; net revenue is approximately GMV times the take rate.

Take rate

The percentage of GMV a marketplace retains as revenue through commissions, listing fees, or services. Revenue equals GMV multiplied by the effective take rate after discounts and refunds.

LTV to CAC ratio

Customer lifetime value divided by customer acquisition cost. LTV equals average revenue per user times gross margin times retention months; a ratio of three or more is a common viability benchmark.

O2O model

Online-to-offline commerce: customers discover and pay online, then receive goods or services at a physical location. Success depends on offline inventory accuracy and fulfillment coordination.

Two-sided network effect

A marketplace becomes more valuable as both buyer and seller populations grow, because more sellers improve selection and more buyers improve seller incentives. Liquidity in a niche is a durable advantage.

Non-functional requirements

Quality attributes such as performance, availability, security, and usability that constrain how a system performs its functions. They must be stated measurably, for example p95 latency under two seconds.

Balanced data flow diagram

A leveled DFD in which the inputs and outputs of a parent process match the external flows of its child diagram. Balancing prevents requirements from appearing or vanishing between levels.

MoSCoW prioritization

A scoping method classifying requirements as Must have, Should have, Could have, or Won't have this time. It fixes the minimum viable release and makes scope trade-offs explicit to stakeholders.

Feasibility analysis

Assessment of whether a proposed system is viable across technical, economic, operational, and legal dimensions. Economic feasibility compares total cost of ownership with quantified benefits such as payback period.

CAP theorem

A distributed data store cannot simultaneously guarantee consistency, availability, and partition tolerance. Under a network partition it must choose consistency or availability, which guides catalog versus payment design.

Idempotency key

A unique client-supplied identifier attached to an order or payment request so retries return the original result instead of creating duplicates. The key and result are stored together.

Cache-aside pattern

The application reads from cache first, loads from the database on a miss, then populates the cache. Writes update the database and invalidate the cached entry to limit staleness.

Stateless application tier

Servers hold no client session state, so any node can serve any request. Sessions move to a shared store or signed token, enabling horizontal scaling behind a load balancer.

Composite availability

Overall availability of components in series equals the product of individual availabilities, so 99.9% times 99.9% is about 99.8%. Redundancy is required to raise the combined figure.

HTTP idempotent methods

GET, PUT, and DELETE produce the same server state when repeated, so clients may safely retry them. POST is neither safe nor idempotent, so retries need an idempotency key.

Progressive Web App

A web application using service workers, a manifest, and HTTPS to support offline caching, push notifications, and home-screen installation without distribution through an app store.

Content Security Policy

An HTTP response header restricting which script, style, and frame sources a browser may load. It mitigates cross-site scripting by blocking inline and unauthorized external scripts.

Core Web Vitals

User-experience metrics reported by browsers: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability.

Third normal form

A relational table is in 3NF when it is in 2NF and no non-key attribute depends transitively on the primary key. It removes redundancy that causes update anomalies.

Optimistic locking

Concurrency control where a row carries a version number; an update succeeds only if the version is unchanged. It prevents lost updates and overselling without holding database locks.

Leftmost prefix rule

A composite index on columns a and b can serve queries filtering on a, or on a and b, but not on b alone. Column order in the index therefore matters.

Recovery point objective

The maximum acceptable amount of data loss measured in time. It drives backup and transaction-log frequency, while recovery time objective sets the acceptable restore duration.

Tokenization in payments

Replacing a card number with a surrogate token held by the payment provider. Merchants store only the token, reducing PCI DSS scope and breach exposure.

Asynchronous payment callback

The gateway notifies the merchant server of the final payment result at a callback URL. Merchants must verify the signature, handle repeats idempotently, and reconcile with settlement files.

Digital signature

A cryptographic value created with the sender's private key and verified with the public key. It provides integrity, origin authenticity, and non-repudiation for the signed message.

Web application firewall

A reverse-proxy security control inspecting HTTP traffic for application-layer attacks such as SQL injection and cross-site scripting, blocking requests that match known malicious patterns.

RFM segmentation

Customer grouping by recency of last purchase, purchase frequency, and monetary value. It guides retention targeting, for example reactivation offers for high-value lapsed buyers.

Inventory turnover

Cost of goods sold divided by average inventory value over a period. Higher turnover means faster capital recovery; very high turnover can signal stockout risk.

Cart abandonment rate

The share of shopping sessions with items in the cart that end without a paid order. It is reduced by transparent shipping costs, guest checkout, and saved-cart reminders.

Earned value management

Project control using planned value, earned value, and actual cost. Cost performance index equals earned value divided by actual cost; below one means over budget.

Critical path

The longest sequence of dependent activities through a project network. It determines the shortest possible duration, and its activities have zero total float.

Shall versus should

In specifications, shall denotes a mandatory requirement, should a recommended one, and may an optional one. Misreading these words changes legal and test acceptance meaning.