develop.kde.org

A free hosted REST API like ReqRes gives you a real HTTP endpoint you can call immediately—no signup, no local server, no database setup. You get predictable JSON responses for users, resources, login, and registration, which makes it useful for front-end demos, integration tests, learning HTTP clients, and prototyping. What it is not is a production backend for your app: the data is shared, resets periodically, and you don't control the schema. If you need persistent, private data with auth and logs, that's where an account-based backend or a commercial licence comes in.

What "free REST API for testing and prototyping" actually means

The phrase sounds vague, so it helps to separate two things people often conflate:

• A mock/sample API — a public, hosted service with fixed or semi-fixed endpoints that return realistic-looking JSON. You don't own the data. It exists so you can point code at a URL and get a response.
• A real backend you configure — a service where you define collections, schemas, authentication, and logging, and where your data persists and belongs to you.

ReqRes's landing page describes both: a free REST API for testing and prototyping with real responses and no signup, plus an option to build your own backend with collections, auth, and logs at app.reqres.in. Those are different products with different trade-offs. The free public endpoints are the "point and go" part; the account-based backend is the "own your data" part.

What you can do with the no-signup public endpoints

1. Front-end demos without a backend

If you're building a UI and need data to render, you can fetch from a public endpoint instead of hardcoding arrays. This keeps your demo code closer to real fetch logic:

async function loadUsers(page = 1) {
  const res = await fetch(`https://reqres.in/api/users?page=${page}`);
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  const { data, total, page: current } = await res.json();
  return { users: data, total, page: current };
}

You get pagination fields, a data array, and support metadata—enough to build list views, loading states, and empty states.

2. Integration and contract tests

You can assert that your HTTP layer handles status codes, headers, and JSON shapes correctly. Typical checks:

• GET /api/users/2 returns 200 with a data object.
• GET /api/users/23 returns 404 (a non-existent user).
• POST /api/login with valid credentials returns a token; with missing fields returns 400.

This is useful for testing your client wrapper, retry logic, error handling, and serialization—without spinning up your own server.

3. Learning HTTP clients and tooling

If you're new to fetch, Axios, curl, Postman, or HTTPie, a hosted API is a low-friction target. You can practice:

• Sending query parameters (?page=2, ?delay=3).
• Setting headers and reading response headers.
• Handling POST, PUT, PATCH, DELETE.
• Observing status codes for success and failure.

4. Deliberate failure and latency testing

Endpoints that return 404 on purpose, or that accept a delay parameter, let you test how your app behaves when things go wrong or slow down. That's hard to do reliably against a happy-path local mock.

What the public endpoints are not good for

The key limitation: you don't own the data, and other people are hitting the same endpoints. Treat responses as illustrative, not authoritative.

When you'd move to an account-based backend

Consider app.reqres.in (collections, auth, logs) when any of these are true:

• You need your own collections and fields, not the fixed demo schema.
• You need data to persist between sessions and belong only to you.
• You need real authentication flows you can rely on in a demo or internal tool.
• You need request logs to debug what your client actually sent.
• You're working with a team and need shared, stable endpoints.

The trade-off is setup and, eventually, cost. The public endpoints require none; the backend requires an account and configuration.

Where pricing and licensing become relevant

The site signals a commercial licence and an upgrade path (with Stripe as the payment platform), but specific prices, plan tiers, and limits aren't stated here—so don't assume numbers. What you can reason about:

• Prototyping and learning → free public endpoints are usually enough.
• Internal tools, demos for clients, or anything you don't want reset → an account-based backend is the natural next step.
• Production or commercial use → check the licence terms and any paid plan, because "free for testing" and "free for commercial production" are not the same thing.

Before committing, read the current terms on the site rather than relying on secondhand summaries, since pricing and licence scope change.

A quick decision checklist

1. Do you need data that persists and is private? If yes → account-based backend.
2. Do you need a custom schema? If yes → account-based backend.
3. Are you only testing HTTP behavior, UI rendering, or learning a client? If yes → free public endpoints.
4. Will this touch real users or revenue? If yes → review the licence and any paid plan first.
5. Do you need logs and team access? If yes → account-based backend.

If you answer "no" to 1, 2, 4, and 5, the free hosted API is likely all you need. If you answer "yes" to any of them, plan for the account-based path.

If you're new to Ahrefs and want to run your first SEO audit, the fastest path is: open Site Explorer, enter your target URL, review the Overview for a health snapshot, then dig into Organic Keywords, Top Pages, and Site Audit to find specific problems. From there, build a short prioritized to-do list instead of trying to fix everything at once.

This tutorial walks through that workflow using a realistic starting scenario, explains what the numbers mean, and shows how to turn findings into actions.

Before You Start: Pick a Narrow Scope

A common beginner mistake is auditing an entire large website on day one. The reports become overwhelming, and you can't tell which issues matter.

Instead, choose one of these starting points:

• A single important page (your homepage or a key product/service page)
• A small site (under ~50 pages, e.g., a personal blog or small business site)
• One section of a bigger site (e.g., /blog/)

For this tutorial, assume you're auditing a small business site with about 30 pages. The same steps scale up later.

You'll need an Ahrefs account to follow along. Ahrefs offers paid plans, and pricing and feature limits change over time, so check the current Pricing page for what's included in each tier before committing.

Step 1: Enter Your Target in Site Explorer

Site Explorer is Ahrefs' core tool for analyzing any website or URL.

1. Open Site Explorer from the top navigation.
2. In the search box, paste your domain (e.g., example.com).
3. Choose the Exact URL or Domain mode depending on scope. For a full-site view, use Domain or Prefix; for a single page, use Exact URL.
4. Press Enter.

You'll land on the Overview report. Don't try to absorb everything — focus on four numbers first.

Reading the Overview Snapshot

Important caveat: Ahrefs' traffic and keyword numbers are estimates based on its own data. They won't match Google Search Console or your analytics exactly. Treat them as directional, not absolute.

Step 2: See What You Already Rank For

Go to Organic Keywords in the left sidebar. This shows queries where your site appears in search results.

Sort by Traffic (descending) to see which pages bring the most estimated visitors. Then look for:

• Keywords ranking in positions 4–15 — these are often the easiest wins. A small content or on-page improvement can push them onto page one.
• Keywords with high volume but low position — potential opportunities if the topic is relevant.
• Irrelevant keywords — if you rank for something off-topic, it may signal thin or mismatched content.

Write down 5–10 of the position 4–15 keywords. These become your first optimization targets.

Step 3: Find Your Best and Weakest Pages

Open Top Pages. This ranks your URLs by estimated organic traffic.

Look for two things:

1. Your top performers — understand what topics and formats work. Can you create more content like this?
2. Pages with traffic but poor rankings — these may need on-page fixes (title, headings, internal links).

If a page gets zero traffic and targets a topic you care about, it's a candidate for a rewrite or consolidation.

Step 4: Run a Technical Site Audit

Now move to Site Audit. This crawls your site and flags technical and on-page issues.

1. Click Site Audit → New project.
2. Enter your domain and set crawl settings (default is usually fine for a small site).
3. Start the crawl and wait for it to finish.

Once complete, you'll see a Health Score and a list of issues grouped by category.

Which Issues to Fix First

Not all issues are equal. Prioritize in this order:

Ignore low-impact warnings (like minor meta description length) until the big items are handled.

Step 5: Turn Findings Into a To-Do List

You now have raw data. Convert it into a short, actionable list. Example:

1. Fix 3 broken links found in Site Audit.
2. Rewrite title tags on 5 pages with duplicate titles.
3. Improve 4 pages ranking in positions 6–12 by adding missing subtopics and internal links.
4. Remove or update 2 thin pages with no traffic.

Keep the list to 5–10 items max for your first audit. Finishing a short list beats starting a long one.

Common Beginner Mistakes

• Chasing every red flag. Site Audit flags many minor issues. Fix what affects rankings and users first.
• Trusting estimates as exact numbers. Ahrefs data is modeled, not measured from your analytics.
• Auditing a huge site too early. Start small to learn the interface.
• Ignoring search intent. A page can be technically perfect but still fail if it doesn't match what searchers want.
• Forgetting to re-crawl. After fixes, run Site Audit again to confirm improvements.

Where to Go Next

Once your first audit is done:

• Compare with competitors using Site Explorer's Competing Domains and Content Gap reports.
• Track keyword rankings over time with Rank Tracker.
• Explore backlink opportunities in the Backlinks and Link Intersect reports.
• Set up recurring Site Audit crawls so new issues surface automatically.

Your first audit isn't about perfection — it's about building a repeatable habit: enter a target, read the key reports, pick the highest-impact fixes, and act. Do that once a month and your site's health compounds.

Kirigami is a UI framework from KDE for building convergent applications — apps that run on phones, TVs, desktops, and everything in between from a single codebase. It is built on top of Qt and the KDE Frameworks, so if you already write Qt/QML code, Kirigami gives you ready-made components and layout patterns that adapt to different screen sizes and input methods. It is the right choice when you want one application to feel native on both desktop Linux and mobile or embedded targets, rather than maintaining separate UIs per platform.

What Kirigami actually is

Kirigami is a set of QML components and design conventions layered on Qt Quick. Instead of hand-rolling navigation, page structure, and adaptive layouts for each form factor, you compose your interface from Kirigami's building blocks and let them respond to the available space.

The KDE Developer Platform describes it as a way to "build convergent apps that run on phones, TVs and everything in between," noting that "applications using Kirigami adapt brilliantly to mobile, desktop, TVs, infotainment systems and everything in between."

Two properties matter most for cross-platform work:

• Adaptive components — the same UI rearranges itself as the window or screen changes, rather than requiring separate mobile and desktop layouts.
• Consistent, defined workflow — Kirigami ships opinionated components and a clearly defined workflow, so you spend less time inventing navigation patterns and more time on your app's actual features.

How it helps with cross-platform development

One codebase, many targets

Because Kirigami sits on Qt, the same application can be deployed across desktop Linux, Android, Windows, macOS, embedded systems, and more. The KDE platform page frames this as "Develop once, deploy everywhere," with KDE technologies working on every platform Qt supports.

Convergence instead of separate UIs

The line between desktop and mobile is blurring, and users expect comparable quality on every device. Kirigami's components are designed to look good and stay consistent across form factors, and the framework provides a defined workflow so your app behaves predictably whether it is running on a phone, a TV, or a desktop.

A foundation you don't have to build

Kirigami is part of the broader KDE stack. KDE Frameworks covers roughly 80 add-on libraries for programming with Qt, all tested in real-world scenarios and documented, and distributed under LGPL or MIT licenses. That means the adaptive UI layer is backed by a large, permissively licensed library set rather than being a standalone widget kit.

When Kirigami is a good fit

Getting started

1. Learn the KDE development basics. The platform's Tutorials section covers how to develop KDE software, which gives you the QML and Frameworks context Kirigami assumes.
2. Read the design guidance. KDE's human interface guidelines explain the conventions Kirigami components follow, so your app looks and behaves consistently with the ecosystem.
3. Explore Kirigami specifically. The platform provides a dedicated Kirigami entry point for making your next KDE application.
4. Check the API docs. API documentation for KDE's development libraries is available when you need details on specific components.
5. Pick an IDE. KDevelop is a cross-platform IDE for C, C++, Python, QML/JavaScript, and PHP — useful since Kirigami apps are typically written in QML.

The expected result at the end of this path is a single QML application whose interface adapts across the platforms Qt supports, using components you did not have to design from scratch.

Common sticking points

• Assuming convergence is automatic. Kirigami provides adaptive components, but you still choose how your content reflows. The framework gives you the tools; the layout decisions are yours.
• Skipping the design guidelines. Kirigami's value includes consistency. Ignoring KDE's HIG works against that.
• Forgetting the Qt dependency. Kirigami is not a standalone toolkit — it inherits Qt's platform support and constraints.

For the authoritative component list, licensing text, and current documentation, start at the KDE Developer Platform and follow its Kirigami and API sections.

develop.kde.org is the official resource hub for building software with KDE technologies. It gathers design guidance, tutorials, API documentation, distribution help, and multi-platform development material in one place, aimed at developers who want to create applications using KDE's libraries and tools. If you already work with Qt or are considering it, this site is the starting point for the KDE-specific layer on top.

What the site covers

The platform is organized around five areas, each answering a different stage of the development process:

The through-line is "design, build and distribute beautiful, usable applications with KDE technologies" — so the site is meant to follow a project from interface decisions through to release, not just to host reference docs.

KDE Frameworks: the Qt add-on layer

KDE Frameworks is the foundation most of the site's guidance builds on. It covers 80 add-on libraries for programming with Qt. According to the site, all of these libraries have been tested in real-world scenarios and are comprehensively documented, and they are distributed under LGPL or MIT licenses.

That licensing detail matters if you are evaluating whether KDE code can fit into your project: both licenses are permissive enough for a wide range of uses, but they are not identical, so check the specific library you plan to depend on.

Kirigami and convergent apps

Kirigami is KDE's toolkit for building what the site calls convergent apps — applications that run on phones, TVs, and everything in between. The premise is that the line between desktop and mobile is blurring, and users expect the same quality of experience on every device.

Applications built with Kirigami are described as adapting to mobile, desktop, TVs, infotainment systems, and similar targets. The components are presented as good-looking and consistent, and Kirigami provides a clearly defined workflow. If your goal is one codebase that scales across screen sizes and input methods, this is the part of the platform to read first.

Multi-platform reach

KDE's technologies are built on top of Qt, and the site states they work on every platform — listing desktop Linux, Android, Windows, macOS, and embedded among them. The framing is "develop once, deploy everywhere." For planning purposes, treat that as the intended design goal and verify your specific target combination against the API docs, since platform support can vary by library.

KDevelop: the IDE

The site also points to KDevelop, a cross-platform IDE for C, C++, Python, QML/JavaScript, and PHP. It is described as open source, powerful, and fast, offering a seamless environment for projects of any size. If you want a single tool that matches the languages KDE development commonly uses, KDevelop is the recommended entry point from this page.

How to use the site

A practical path through the material:

1. Read the design guidelines if you are making interface decisions, so your app matches KDE conventions.
2. Work through the tutorials to learn how KDE software is structured in practice.
3. Consult the API docs for the specific libraries you depend on.
4. Check the distribution section when you are ready to reach users.
5. Review the multi-platform material if you intend to ship beyond a single target.

If you are deciding whether to start here at all: the site is most useful when you are already committed to Qt and want the KDE ecosystem's conventions, libraries, and tooling. If you have not chosen a framework yet, the multi-platform and Kirigami pages are the quickest way to judge whether KDE's approach fits your project.

KDE Frameworks are a collection of 80 add-on libraries for programming with Qt. They sit on top of Qt and add functionality that Qt itself does not provide, covering areas such as configuration, file handling, notifications, and UI components. All of the libraries have been tested in real-world scenarios and are comprehensively documented, and they are distributed under LGPL or MIT licenses. If you are already building with Qt and need more than the base toolkit offers, KDE Frameworks are the layer to look at.

How KDE Frameworks Relate to Qt

Qt provides the core cross-platform application and UI toolkit. KDE Frameworks build on that foundation rather than replacing it. The relationship is additive:

• Qt gives you the base classes for windows, widgets, networking, and QML.
• KDE Frameworks add 80 libraries that extend those capabilities with higher-level, production-tested components.

Because they are built on Qt, anything you write with KDE Frameworks inherits Qt's cross-platform behavior. The KDE Developer Platform describes them as enhancing the Qt experience — the goal is to save you from reinventing common infrastructure.

What the Libraries Cover

The 80 libraries span a wide range of concerns. Rather than listing all of them, it helps to think in categories:

Each library is independently usable, so you can adopt only the pieces your project needs instead of pulling in the whole set.

Why the Testing and Documentation Matter

Two claims from the platform are worth taking at face value when you evaluate the libraries:

1. Well-tested in real-world scenarios. These libraries are not experimental side projects. They are used across KDE software, which means edge cases around platform differences and long-running usage have already been exercised.
2. Comprehensively documented. Each library ships with API documentation, so you can check interfaces before committing to a dependency.

For a developer choosing a dependency, both reduce risk: you are less likely to hit undocumented behavior, and you have a reference to work from.

Licensing: LGPL or MIT

The libraries are distributed under LGPL or MIT licenses. Both are permissive enough for a wide range of projects, including commercial ones, though the exact terms differ:

• MIT is a short permissive license with minimal restrictions.
• LGPL allows use in proprietary applications under certain conditions, typically involving dynamic linking.

Check the specific license of each library you adopt, since the collection is not under a single uniform license.

Where Frameworks Fit Alongside Kirigami and KDevelop

KDE Frameworks are one part of a larger development stack described on the platform:

• Kirigami is a UI framework for building convergent apps — applications that adapt to phones, desktops, TVs, and infotainment systems from a single codebase. It is built on top of KDE's technologies and Qt.
• KDevelop is a cross-platform IDE for C, C++, Python, QML/JavaScript, and PHP. It is open source, and the platform describes it as powerful and fast, suitable for projects of any size.

In practice, you might use KDE Frameworks for backend and integration functionality, Kirigami for the interface layer, and KDevelop as your editing environment. They are complementary, not competing choices.

Multi-Platform Reach

Because KDE's technologies are built on Qt, they work across desktop Linux, Android, Windows, macOS, embedded systems, and more. The platform's framing is "develop once, deploy everywhere." This matters if you need a single codebase targeting both desktop and mobile — the convergence goal that Kirigami and the underlying frameworks are designed to support.

When to Use KDE Frameworks

Consider them when:

• You are already developing with Qt and need functionality Qt does not include out of the box.
• You want libraries that have been validated in real applications rather than newly written utilities.
• You need a permissive license (LGPL or MIT) for your project.
• You are targeting multiple platforms and want consistent behavior across them.

If you are starting fresh and only need basic Qt features, the base toolkit may be enough. KDE Frameworks become valuable as your requirements grow beyond what Qt provides directly.

To go further, the platform points to tutorials for learning KDE software development, API documentation for the development libraries, and guidance on distributing your app to users.