EduByte.tech
Start learning
Certifications

Proof,
not promises.

A certificate should survive a second look. Every EduByte credential is tied to an assessed exam, an issuer-controlled record and a live public status that anyone can check.

Choose a program Verify a credential
80% pass threshold · 3 attempts (5 with Pro) · QR verification
EduByte.tech
EduByte · Skills certificationIssued 14 Sept 2026

This certifies that

Amina Rahman

has successfully completed the assessed program

HTML Foundations

Credential IDEB-HTML-8F3K-2Q7M
Program codeEB-HTML-01
Scan to verify
www.edubyte.tech/verify/EB-HTML-8F3K-2Q7M
Sample credential · demonstration only
SampleDemonstration only · not a live record
Programs

Start with a skill you can prove.

Each certification is attached to a complete course. The exam unlocks only when the lessons are done.

Browse courses
Actix Web cover illustration
EB-ACTIX-01Advanced

Actix Web Quick Track

A high-performance Rust web framework.

15 min 80% to pass 5 questions
Skills certificationView program
AI Literacy for Developers cover illustration
EB-AI-01Beginner

AI Literacy Certificate

Use AI tools without outsourcing your judgement.

30 min 80% to pass 10 questions
Skills certificationView program
AJAX & Async Requests cover illustration
EB-AJAX-01Beginner

AJAX & Async Requests Certificate

Update the page without a full reload.

30 min 80% to pass 10 questions
Skills certificationView program
Angular cover illustration
EB-NG-01Intermediate

Angular Certificate

A batteries-included framework for large, typed applications.

30 min 80% to pass 10 questions
Skills certificationView program
Ansible cover illustration
EB-ANS-01Intermediate

Ansible Quick Track

Agentless configuration management.

15 min 80% to pass 5 questions
Skills certificationView program
Apache Airflow cover illustration
EB-AF-01Intermediate

Airflow Quick Track

Orchestrate data pipelines as code.

15 min 80% to pass 5 questions
Skills certificationView program
Apache Kafka cover illustration
EB-KAFKA-01Intermediate

Kafka Quick Track

Event streaming for distributed systems.

15 min 80% to pass 5 questions
Skills certificationView program
Apache Spark cover illustration
EB-SPARK-01Advanced

Spark Quick Track

Distributed data processing at scale.

15 min 80% to pass 5 questions
Skills certificationView program
AppML cover illustration
EB-APPML-01Beginner

AppML Quick Track

W3Schools’ data-driven HTML framework.

15 min 80% to pass 5 questions
Skills certificationView program
ASP.NET Core cover illustration
EB-ASPNET-01Intermediate

ASP.NET Core Quick Track

Cross-platform .NET web services.

15 min 80% to pass 5 questions
Skills certificationView program
Assembly cover illustration
EB-ASM-01Advanced

Assembly Quick Track

Read the layer beneath every language.

15 min 80% to pass 5 questions
Skills certificationView program
Astro cover illustration
EB-ASTRO-01Intermediate

Astro Quick Track

Content-first sites with islands of interactivity.

15 min 80% to pass 5 questions
Skills certificationView program
AWS cover illustration
EB-AWS-01Beginner

AWS Quick Track

Amazon Web Services fundamentals.

15 min 80% to pass 5 questions
Skills certificationView program
Azure cover illustration
EB-AZ-01Beginner

Azure Quick Track

Microsoft cloud fundamentals.

15 min 80% to pass 5 questions
Skills certificationView program
Bash & Linux cover illustration
EB-SH-01Beginner

Bash & Linux Certificate

The terminal skills every developer uses every day.

30 min 80% to pass 10 questions
Skills certificationView program
BigQuery cover illustration
EB-BQ-01Intermediate

BigQuery Quick Track

Serverless analytics on Google Cloud.

15 min 80% to pass 5 questions
Skills certificationView program
Bootstrap 5 cover illustration
EB-BS-01Beginner

Bootstrap 5 Certificate

Ship polished responsive interfaces without writing every rule.

30 min 80% to pass 10 questions
Skills certificationView program
C Programming cover illustration
EB-C-01Beginner

C Programming Certificate

Understand the machine underneath every language.

30 min 80% to pass 10 questions
Skills certificationView program
C# Foundations cover illustration
EB-CS-01Beginner

C# Foundations Certificate

A modern, typed language for apps, APIs and games.

30 min 80% to pass 10 questions
Skills certificationView program
C++ Foundations cover illustration
EB-CPP-01Intermediate

C++ Foundations Certificate

Expressive systems programming with clear ownership.

30 min 80% to pass 10 questions
Skills certificationView program
CI/CD cover illustration
EB-CICD-01Beginner

CI/CD Quick Track

Automate tests and deployments.

15 min 80% to pass 5 questions
Skills certificationView program
Classic ASP cover illustration
EB-ASP-01Beginner

Classic ASP Quick Track

VBScript server pages still found in older estates.

15 min 80% to pass 5 questions
Skills certificationView program
ClickHouse cover illustration
EB-CH-01Advanced

ClickHouse Quick Track

Columnar analytics for huge datasets.

15 min 80% to pass 5 questions
Skills certificationView program
Clojure cover illustration
EB-CLJ-01Advanced

Clojure Quick Track

A Lisp for the JVM with immutable data.

15 min 80% to pass 5 questions
Skills certificationView program
Cloud Security cover illustration
EB-CSEC-01Intermediate

Cloud Security Quick Track

Identity, network and data protection in the cloud.

15 min 80% to pass 5 questions
Skills certificationView program
Cloudflare cover illustration
EB-CF-01Beginner

Cloudflare Quick Track

CDN, DNS, security and edge compute.

15 min 80% to pass 5 questions
Skills certificationView program
COBOL cover illustration
EB-COB-01Beginner

COBOL Quick Track

The language still processing banking and insurance.

15 min 80% to pass 5 questions
Skills certificationView program
CSS Essentials cover illustration
EB-CSS-01Beginner

CSS Essentials Certificate

Design interfaces that adapt to every screen.

32 min 80% to pass 16 questions
Skills certificationView program
Cybersecurity Foundations cover illustration
EB-SEC-01Beginner

Cybersecurity Foundations Certificate

Think like an attacker; build like an engineer.

30 min 80% to pass 10 questions
Skills certificationView program
Dart cover illustration
EB-DART-01Beginner

Dart Quick Track

The language behind Flutter.

15 min 80% to pass 5 questions
Skills certificationView program
Data Structures & Algorithms cover illustration
EB-DSA-01Intermediate

Data Structures & Algorithms Certificate

Choose the right tool and reason about cost.

30 min 80% to pass 10 questions
Skills certificationView program
Data Visualisation cover illustration
EB-DV-01Beginner

Data Visualisation Quick Track

Charts that make the comparison obvious.

15 min 80% to pass 5 questions
Skills certificationView program
Databricks cover illustration
EB-DBX-01Advanced

Databricks Quick Track

Lakehouse analytics with Spark and notebooks.

15 min 80% to pass 5 questions
Skills certificationView program
dbt cover illustration
EB-DBT-01Intermediate

dbt Quick Track

Transform data with SQL and tests.

15 min 80% to pass 5 questions
Skills certificationView program
DevSecOps cover illustration
EB-DSO-01Intermediate

DevSecOps Quick Track

Security inside the delivery pipeline.

15 min 80% to pass 5 questions
Skills certificationView program
Django cover illustration
EB-DJ-01Intermediate

Django Certificate

The batteries-included Python web framework.

30 min 80% to pass 10 questions
Skills certificationView program
Docker Foundations cover illustration
EB-DOCKER-01Beginner

Docker Foundations Certificate

Package software once and run it anywhere.

30 min 80% to pass 10 questions
Skills certificationView program
DuckDB cover illustration
EB-DUCK-01Beginner

DuckDB Quick Track

Analytical SQL that runs anywhere.

15 min 80% to pass 5 questions
Skills certificationView program
Elasticsearch cover illustration
EB-ES-01Intermediate

Elasticsearch Quick Track

Search and analytics at scale.

15 min 80% to pass 5 questions
Skills certificationView program
Elixir cover illustration
EB-ELIXIR-01Intermediate

Elixir Quick Track

Functional, concurrent programming on the Erlang VM.

15 min 80% to pass 5 questions
Skills certificationView program
Ethical Hacking cover illustration
EB-EH-01Intermediate

Ethical Hacking Quick Track

Test systems with permission and discipline.

15 min 80% to pass 5 questions
Skills certificationView program
Excel cover illustration
EB-XL-01Beginner

Excel Quick Track

Spreadsheet analysis that runs the business world.

15 min 80% to pass 5 questions
Skills certificationView program
Express cover illustration
EB-EXP-01Beginner

Express Quick Track

The minimal Node.js web framework.

15 min 80% to pass 5 questions
Skills certificationView program
F# cover illustration
EB-FS-01Intermediate

F# Quick Track

Functional-first programming on .NET.

15 min 80% to pass 5 questions
Skills certificationView program
FastAPI cover illustration
EB-FAPI-01Intermediate

FastAPI Quick Track

Typed Python APIs with automatic docs.

15 min 80% to pass 5 questions
Skills certificationView program
Fastify cover illustration
EB-FFY-01Intermediate

Fastify Quick Track

A fast, schema-driven Node.js framework.

15 min 80% to pass 5 questions
Skills certificationView program
Flask cover illustration
EB-FLASK-01Beginner

Flask Quick Track

A small Python web framework.

15 min 80% to pass 5 questions
Skills certificationView program
Fortran cover illustration
EB-FTN-01Intermediate

Fortran Quick Track

Scientific computing that still runs the world’s simulations.

15 min 80% to pass 5 questions
Skills certificationView program
Gin cover illustration
EB-GIN-01Intermediate

Gin Quick Track

A fast HTTP framework for Go.

15 min 80% to pass 5 questions
Skills certificationView program
Git & GitHub cover illustration
EB-GIT-01Beginner

Git & GitHub Certificate

Work like a professional team, even when you are solo.

32 min 80% to pass 16 questions
Skills certificationView program
Go Foundations cover illustration
EB-GO-01Beginner

Go Foundations Certificate

Small language, direct concurrency, fast services.

30 min 80% to pass 10 questions
Skills certificationView program
Google Cloud cover illustration
EB-GCP-01Beginner

GCP Quick Track

Google Cloud Platform fundamentals.

15 min 80% to pass 5 questions
Skills certificationView program
Google Sheets cover illustration
EB-GS-01Beginner

Google Sheets Quick Track

Collaborative spreadsheets in the browser.

15 min 80% to pass 5 questions
Skills certificationView program
GraphQL cover illustration
EB-GQL-01Intermediate

GraphQL Quick Track

A typed query language for APIs.

15 min 80% to pass 5 questions
Skills certificationView program
Groovy cover illustration
EB-GR-01Beginner

Groovy Quick Track

A dynamic JVM language with concise syntax.

15 min 80% to pass 5 questions
Skills certificationView program
gRPC cover illustration
EB-GRPC-01Advanced

gRPC Quick Track

Typed, efficient service-to-service RPC.

15 min 80% to pass 5 questions
Skills certificationView program
Haskell cover illustration
EB-HS-01Advanced

Haskell Quick Track

A pure, statically typed functional language.

15 min 80% to pass 5 questions
Skills certificationView program
HTML Foundations cover illustration
EB-HTML-01Beginner

HTML Foundations Certificate

Build the structure of every page on the web.

32 min 80% to pass 16 questions
Skills certificationView program
Incident Response cover illustration
EB-IR-01Intermediate

Incident Response Quick Track

Handle security incidents without making them worse.

15 min 80% to pass 5 questions
Skills certificationView program
Java Foundations cover illustration
EB-JAVA-01Beginner

Java Foundations Certificate

Structured, portable software for real systems.

30 min 80% to pass 10 questions
Skills certificationView program
JavaScript Foundations cover illustration
EB-JS-01Beginner

JavaScript Foundations Certificate

Make pages think, react and remember.

32 min 80% to pass 16 questions
Skills certificationView program
jQuery cover illustration
EB-JQ-01Beginner

jQuery Certificate

Read and maintain the library behind millions of sites.

30 min 80% to pass 10 questions
Skills certificationView program
Julia cover illustration
EB-JL-01Beginner

Julia Quick Track

Fast numerical computing with a friendly syntax.

15 min 80% to pass 5 questions
Skills certificationView program
Kotlin cover illustration
EB-KT-01Beginner

Kotlin Certificate

A concise, null-safe language for Android and the JVM.

30 min 80% to pass 10 questions
Skills certificationView program
Kubernetes cover illustration
EB-K8S-01Intermediate

Kubernetes Certificate

Run containers reliably without hand-managing machines.

30 min 80% to pass 10 questions
Skills certificationView program
Laravel cover illustration
EB-LARA-01Intermediate

Laravel Quick Track

A full-stack PHP framework.

15 min 80% to pass 5 questions
Skills certificationView program
Lua cover illustration
EB-LUA-01Beginner

Lua Quick Track

A small, fast language embedded in games and tools.

15 min 80% to pass 5 questions
Skills certificationView program
Machine Learning Basics cover illustration
EB-ML-01Intermediate

Machine Learning Basics Certificate

Build honest models, measure them properly and know their limits.

30 min 80% to pass 10 questions
Skills certificationView program
MATLAB cover illustration
EB-MATLAB-01Beginner

MATLAB Quick Track

Numerical computing and engineering analysis.

15 min 80% to pass 5 questions
Skills certificationView program
Microservices cover illustration
EB-MS-01Advanced

Microservices Quick Track

Design and operate small, independent services.

15 min 80% to pass 5 questions
Skills certificationView program
MongoDB Foundations cover illustration
EB-MONGO-01Beginner

MongoDB Foundations Certificate

Model documents, query them precisely and grow safely.

30 min 80% to pass 10 questions
Skills certificationView program
MySQL cover illustration
EB-MYSQL-01Beginner

MySQL Certificate

The database behind a huge share of the web.

30 min 80% to pass 10 questions
Skills certificationView program
NestJS cover illustration
EB-NEST-01Advanced

NestJS Quick Track

Structured Node.js with modules and dependency injection.

15 min 80% to pass 5 questions
Skills certificationView program
Networking & HTTP cover illustration
EB-NET-01Beginner

Networking & HTTP Certificate

Understand what happens between a click and a response.

30 min 80% to pass 10 questions
Skills certificationView program
Next.js cover illustration
EB-NEXT-01Intermediate

Next.js Quick Track

React with routing, rendering and APIs built in.

15 min 80% to pass 5 questions
Skills certificationView program
Nginx cover illustration
EB-NGX-01Intermediate

Nginx Quick Track

The reverse proxy in front of most of the web.

15 min 80% to pass 5 questions
Skills certificationView program
Nim cover illustration
EB-NIM-01Intermediate

Nim Quick Track

Python-like syntax with C-level performance.

15 min 80% to pass 5 questions
Skills certificationView program
Node.js Foundations cover illustration
EB-NODE-01Intermediate

Node.js Foundations Certificate

Build the server side with the language you already know.

30 min 80% to pass 10 questions
Skills certificationView program
Nuxt cover illustration
EB-NUXT-01Intermediate

Nuxt Quick Track

Vue with routing, data fetching and server routes.

15 min 80% to pass 5 questions
Skills certificationView program
Observability cover illustration
EB-OBS-01Intermediate

Observability Quick Track

Logs, metrics and traces that explain production.

15 min 80% to pass 5 questions
Skills certificationView program
OCaml cover illustration
EB-OCAML-01Advanced

OCaml Quick Track

A pragmatic functional language with a strong type system.

15 min 80% to pass 5 questions
Skills certificationView program
Oracle SQL cover illustration
EB-ORA-01Intermediate

Oracle SQL Quick Track

SQL for Oracle Database.

15 min 80% to pass 5 questions
Skills certificationView program
Pandas & Data Analysis cover illustration
EB-PD-01Beginner

Pandas & Data Analysis Certificate

Turn messy tables into answers you can defend.

30 min 80% to pass 10 questions
Skills certificationView program
Perl cover illustration
EB-PL-01Beginner

Perl Quick Track

Text processing and system automation.

15 min 80% to pass 5 questions
Skills certificationView program
Phoenix cover illustration
EB-PHX-01Advanced

Phoenix Quick Track

Productive Elixir web applications.

15 min 80% to pass 5 questions
Skills certificationView program
PHP for the Web cover illustration
EB-PHP-01Beginner

PHP for the Web Certificate

Server-rendered pages, forms, sessions and a real database.

30 min 80% to pass 10 questions
Skills certificationView program
Polars cover illustration
EB-POLARS-01Intermediate

Polars Quick Track

Fast DataFrames in Rust and Python.

15 min 80% to pass 5 questions
Skills certificationView program
PostgreSQL Foundations cover illustration
EB-PG-01Intermediate

PostgreSQL Foundations Certificate

The relational database behind serious applications.

30 min 80% to pass 10 questions
Skills certificationView program
Power BI cover illustration
EB-PBI-01Beginner

Power BI Quick Track

Business intelligence in the Microsoft stack.

15 min 80% to pass 5 questions
Skills certificationView program
PowerShell cover illustration
EB-PS-01Beginner

PowerShell Quick Track

Automate Windows and cross-platform tasks with objects.

15 min 80% to pass 5 questions
Skills certificationView program
Progressive Web Apps cover illustration
EB-PWA-01Intermediate

PWA Quick Track

Installable, offline-capable web apps.

15 min 80% to pass 5 questions
Skills certificationView program
Python Foundations cover illustration
EB-PY-01Beginner

Python Foundations Certificate

The most readable way to start programming.

32 min 80% to pass 16 questions
Skills certificationView program
R cover illustration
EB-R-01Beginner

R Quick Track

Statistical computing and data analysis.

15 min 80% to pass 5 questions
Skills certificationView program
Raspberry Pi cover illustration
EB-RPI-01Beginner

Raspberry Pi Quick Track

Small computers, GPIO and Linux projects.

15 min 80% to pass 5 questions
Skills certificationView program
React Foundations cover illustration
EB-REACT-01Intermediate

React Foundations Certificate

Build interfaces from small, predictable components.

30 min 80% to pass 10 questions
Skills certificationView program
Redis cover illustration
EB-REDIS-01Intermediate

Redis Quick Track

In-memory data structures for speed.

15 min 80% to pass 5 questions
Skills certificationView program
Remix cover illustration
EB-REMIX-01Intermediate

Remix Quick Track

Web fundamentals with nested routes and server data.

15 min 80% to pass 5 questions
Skills certificationView program
Ruby on Rails cover illustration
EB-RAILS-01Intermediate

Rails Quick Track

Convention-driven full-stack development.

15 min 80% to pass 5 questions
Skills certificationView program
Rust Foundations cover illustration
EB-RUST-01Intermediate

Rust Foundations Certificate

Ownership, safety and performance without a garbage collector.

30 min 80% to pass 10 questions
Skills certificationView program
Sass cover illustration
EB-SASS-01Intermediate

Sass Certificate

A better stylesheet language that compiles to CSS.

30 min 80% to pass 10 questions
Skills certificationView program
Scala cover illustration
EB-SCALA-01Intermediate

Scala Quick Track

Functional and object-oriented programming on the JVM.

15 min 80% to pass 5 questions
Skills certificationView program
Snowflake cover illustration
EB-SNOW-01Intermediate

Snowflake Quick Track

Cloud data warehouse with separated compute and storage.

15 min 80% to pass 5 questions
Skills certificationView program
Solidity cover illustration
EB-SOL-01Intermediate

Solidity Quick Track

Smart contracts for the EVM.

15 min 80% to pass 5 questions
Skills certificationView program
SolidJS cover illustration
EB-SOLID-01Intermediate

SolidJS Quick Track

Fine-grained reactivity with JSX.

15 min 80% to pass 5 questions
Skills certificationView program
Spring Boot cover illustration
EB-SPRING-01Advanced

Spring Boot Quick Track

Production Java services with minimal setup.

15 min 80% to pass 5 questions
Skills certificationView program
SQL & Databases cover illustration
EB-SQL-01Beginner

SQL Fundamentals Certificate

Ask better questions of your data.

32 min 80% to pass 16 questions
Skills certificationView program
SQL Server cover illustration
EB-MSSQL-01Intermediate

SQL Server Quick Track

Microsoft’s relational database.

15 min 80% to pass 5 questions
Skills certificationView program
Statistics cover illustration
EB-STAT-01Beginner

Statistics Quick Track

Reason about data without being fooled.

15 min 80% to pass 5 questions
Skills certificationView program
Svelte cover illustration
EB-SVELTE-01Intermediate

Svelte Quick Track

Compiled reactivity without a virtual DOM.

15 min 80% to pass 5 questions
Skills certificationView program
SvelteKit cover illustration
EB-SK-01Intermediate

SvelteKit Quick Track

The full-stack framework for Svelte.

15 min 80% to pass 5 questions
Skills certificationView program
Swift cover illustration
EB-SW-01Beginner

Swift Certificate

Apple’s language for apps across every device.

30 min 80% to pass 10 questions
Skills certificationView program
Tableau cover illustration
EB-TAB-01Beginner

Tableau Quick Track

Visual analytics with drag-and-drop.

15 min 80% to pass 5 questions
Skills certificationView program
Tailwind CSS cover illustration
EB-TW-01Intermediate

Tailwind CSS Certificate

Build interfaces with utilities, tokens and a real design system.

30 min 80% to pass 10 questions
Skills certificationView program
Tauri cover illustration
EB-TAURI-01Intermediate

Tauri Quick Track

Small, secure desktop apps with web UI and Rust.

15 min 80% to pass 5 questions
Skills certificationView program
Terraform cover illustration
EB-TF-01Intermediate

Terraform Quick Track

Declarative infrastructure across providers.

15 min 80% to pass 5 questions
Skills certificationView program
TypeScript Foundations cover illustration
EB-TS-01Intermediate

TypeScript Foundations Certificate

JavaScript with a compiler on your side.

30 min 80% to pass 10 questions
Skills certificationView program
Unity Foundations cover illustration
EB-UNITY-01Beginner

Unity Foundations Certificate

Turn an idea into a playable 3D scene.

30 min 80% to pass 10 questions
Skills certificationView program
VB.NET cover illustration
EB-VB-01Beginner

VB.NET Quick Track

Visual Basic on the .NET platform.

15 min 80% to pass 5 questions
Skills certificationView program
Vue 3 cover illustration
EB-VUE-01Intermediate

Vue 3 Certificate

The progressive framework for interfaces that stay understandable.

30 min 80% to pass 10 questions
Skills certificationView program
W3.CSS cover illustration
EB-W3CSS-01Beginner

W3.CSS Quick Track

A small utility CSS framework from W3Schools.

15 min 80% to pass 5 questions
Skills certificationView program
Web Security cover illustration
EB-WSEC-01Intermediate

Web Security Quick Track

Defend the browser, session and API.

15 min 80% to pass 5 questions
Skills certificationView program
WebRTC cover illustration
EB-RTC-01Advanced

WebRTC Quick Track

Peer-to-peer audio, video and data.

15 min 80% to pass 5 questions
Skills certificationView program
WebSockets cover illustration
EB-WS-01Intermediate

WebSockets Quick Track

Two-way realtime communication.

15 min 80% to pass 5 questions
Skills certificationView program
XML cover illustration
EB-XML-01Beginner

XML Certificate

Structured data, schemas and the formats built on XML.

30 min 80% to pass 10 questions
Skills certificationView program
Zig cover illustration
EB-ZIG-01Advanced

Zig Quick Track

A small, explicit systems language.

15 min 80% to pass 5 questions
Skills certificationView program
The assessment

Earn it the honest way.

Each exam is drawn from a protected bank, randomized per attempt, and scored against a published threshold. You can see the rules before you begin.

Read the exam policy
01
Complete the course

Finish every published lesson in the track. Progress is explicit, not estimated.

02
Check eligibility

The exam unlocks when all lessons are complete. No hidden requirements.

03
Pass the assessment

A timed, randomized assessment. 80% is required to pass. Three attempts per enrolment, five with Pro.

04
Receive the credential

Get a public credential ID, PDF-ready record and a QR code that resolves to a live status page.

Verification

Anyone can check. In seconds.

The QR code encodes a public verification URL. The verifier checks the issuer registry record, the issuer and the current status — not just what the PDF looks like.

Open the verifier How verification works
ValidRevokedExpiredSupersededUnknown
Scan to test a live sample
Questions

The fine print,
in plain English.

No “accredited” claims, no “fraud-proof” promises. Just a clear description of what the credential is and how it is checked.

Ask a different question
What does a valid result actually prove?

It proves that EduByte’s issuer registry contains this credential and that it is currently active. It does not prove that the person showing you the screen is the named holder.

How do I check a printed certificate?

Scan the QR code or type the credential ID from the certificate into the verifier. The printed PDF is a human-readable copy; the online record is the source of truth.

What should I do if a credential is revoked?

Treat it as no longer valid. The record will show the reason category and, where policy allows, a successor credential.

What happens if I fail an attempt?

You can review your result and retake the assessment within the attempt limit. The first passing result issues the credential. Failed attempts are never published.

Does a certificate expire?

Skills certifications are valid unless revoked or superseded. Where an expiry applies, it is printed on the credential and enforced by the verifier.