Glossary

Server-sent events

SSE

Server-Sent Events

A stream of server-to-client events over HTTP. Reconnection, event IDs and slow consumers need deliberate design; SSE is not a durable broker.

Server-Side Rendering

SSR

Server-Side Rendering

Generating HTML on the server before responding to the browser. Check caching, session data and subsequent hydration consistency.

Service Level Agreement

SLA

Service Level Agreement

An agreement defining service levels and possible consequences of missing them. Distinguish it from an internal SLO and an observed SLI.

Service level indicator

SLI

Service Level Indicator

A measurement of user-relevant service behaviour, such as the fraction of successful responses within a time limit. Define numerator, denominator and measurement window.

Service level objective

SLO

Service Level Objective

A target for a chosen SLI over a time window. It guides reliability decisions and is not automatically a customer SLA.

ServiceAccount

Identity for a Kubernetes workload. RBAC permissions to the cluster API and IAM permissions to AWS services are separate boundaries.

Shallow copy

A new object or collection retaining references to nested objects. Mutating a shared nested object may be visible through both copies.

Short Message Service

SMS

Short Message Service

A text-messaging channel, for example for notifications. API acceptance does not necessarily prove delivery to the recipient.

Simple Factory

A function or object creating a variant from an explicit decision. A static creation method is not automatically the Factory Method pattern.

Single Abstract Method

SAM

Single Abstract Method

A functional contract implemented by a lambda or method reference. Additional default and static methods need not disqualify a functional interface.

Single sign-on

SSO

Single Sign-On

Using multiple applications after authentication through a shared identity provider. Each application still owns its resource-authorization rules.

Single-Page Application

SPA

Single-Page Application

A web application switching views mainly in the browser. The backend must still enforce permissions on every request.

Smoke test

A short check of a critical flow after startup or deployment. Establishes a particular scenario, not full regression coverage or data-recovery evidence.

Software bill of materials

SBOM

Software Bill of Materials

An inventory of software components and versions. It helps assess vulnerability exposure and dependency provenance but is not itself a security-audit result.

Software development kit

SDK

Software Development Kit

Libraries and tools for integrating with a platform or service. They simplify calls, but their retry, timeout, limit and error behaviour must be understood.

SOLID

SOLID

Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion

Principles for assessing responsibilities, dependencies and substitutability. Apply them to concrete change problems rather than as a mandate to add interfaces and classes.

Depending on a sending interface permits a test implementation. This does not require an interface for every class.

SOPS

SOPS

Secrets OPerationS

Encrypts values in configuration files so ciphertext can be versioned. Key access and the location of decryption remain separate operational concerns.

Spring AI

A Spring library for application AI models/tools. It is not an automatically enabled IDE assistant; design permissions/data controls separately.

Spring and Spring Boot

Spring provides dependency management and application integrations; Spring Boot simplifies configuration and startup. Auto-configuration still requires understanding active beans and conditions.

Spring Boot DevTools

Optional Spring Boot development support, including restart after code changes. It is not production process supervision.

SQL

SQL

Structured Query Language

A language for defining, reading and changing relational data. Results depend on schema, data and transactions; query-building code still requires plan and parameter checks.

SQL INSERT

An SQL keyword, not an acronym.

An SQL statement adding rows. Database constraints can reject a conflict independently of an earlier application check.

SQL SELECT

An SQL keyword, not an acronym.

An SQL statement reading data. Reading before writing does not itself reserve a result; appropriate isolation, locking or constraints are needed.

SQLAlchemy

SQL and ORM tooling for Python. Distinguish Core, Session and transaction boundaries; convenient APIs do not remove SQL inspection or resource cleanup.

SQLSTATE

A product name or identifier; no acronym expansion is invented.

A code identifying the class and cause of a SQL outcome or error. Classify errors using stable codes rather than localized message text.

SQS and dead-letter queues

SQS

Simple Queue Service

DLQ

Dead-Letter Queue

SQS is an AWS queue service; a DLQ holds messages requiring separate handling. Design retries, idempotency, monitoring and safe reprocessing.

SRP

SRP

Single Responsibility Principle

A module groups things changing for the same reason; separate pricing from message formatting. It does not mean one method per class.

SSH

SSH

Secure Shell

A protocol for protected remote access and tunnelling. An SSH terminal runs on the remote host; localhost in its commands usually refers to that host.

SSRF

SSRF

Server-Side Request Forgery

Inducing a server to request an attacker-selected destination, such as an internal service. Restrict destinations and protocols outside the application too; consider DNS and redirects.

Stack trace

A list of call frames showing the execution path recorded for an error. A frame usually identifies a function, file and line. Start with the exception type/cause and a frame from your code; the final printed line need not identify the root cause. Do not publish traces containing sensitive data.