Build faster APIs and microservices with the right PHP micro framework
For years, this URL was shared in talks, blog posts and even conference tweets as “the page that lists all PHP micro frameworks”. We are bringing that spirit back with a modern, opinionated guide focused on PHP 8.x, APIs and microservices.
On this page you will learn when a PHP micro framework is the right choice, how it compares to full‑stack frameworks, and how Slim, Flight, Fat‑Free, Leaf and Mezzio fit into real‑world architectures.
Foundations
What is a PHP micro framework?
A PHP micro framework is a deliberately small framework that focuses on the essentials of HTTP: routing, request and response handling, middleware and basic error management. Instead of shipping a full MVC stack, a micro framework gives you a clean core and lets you pick the rest of your stack via Composer.
Compared to a full‑stack framework, a micro framework intentionally does not include everything. There is usually no built‑in ORM, no large templating layer, and no complex authentication module. You compose your application from focused libraries. This keeps the codebase lightweight, predictable and easy to reason about.
What you usually get out‑of‑the‑box
- HTTP routing, often with named routes and route groups.
- Request and response abstractions, ideally PSR‑7 compatible.
- Middleware pipeline for cross‑cutting concerns like logging, CORS and auth.
- Basic error handling and exceptions mapped to HTTP status codes.
- Integration points with dependency injection containers and loggers.
What you plug in yourself
- Database layer or ORM (Doctrine, Eloquent, Cycle, raw PDO, etc.).
- Template engine or frontend framework integration.
- Authentication, authorisation and rate‑limiting.
- API documentation, job queues, event buses and everything else your architecture needs.
This composition model is what makes micro frameworks attractive: you keep control of your architecture while avoiding the boilerplate of writing HTTP plumbing from scratch.
Strategy
When a PHP micro framework is the right choice
Great use cases for micro frameworks
- HTTP APIs and microservices that expose JSON endpoints to frontends, mobile apps or other services.
- Lightweight internal tools: dashboards, admin endpoints, integration utilities and webhook handlers.
- Prototypes and experiments where you want to explore an idea in hours, not weeks, but still keep code clean enough to evolve.
- Thin facades over legacy systems, queues or third‑party APIs, where you primarily orchestrate calls and apply business rules.
- Serverless and FaaS, where cold‑start time and memory usage are critical and every saved millisecond counts.
When a full‑stack framework is a better idea
- You are building a large, feature‑rich monolith with many screens, roles and flows, where a batteries‑included framework like Laravel or Symfony gives you both structure and conventions.
- Several teams will contribute over years, and you want to optimise for shared standards and onboarding speed rather than a minimal footprint.
- You depend heavily on out‑of‑the‑box features such as queues, broadcasting, notifications, jobs and rich admin tooling.
- Your organisation already standardises on a particular framework, with starter kits, libraries and internal tooling around it.
Put simply: micro frameworks maximise freedom, while full‑stack frameworks maximise batteries and convention. The best choice depends on your team, your architecture and your planning horizon.
How we rank PHP micro frameworks
How PHPTrends evaluates modern PHP micro frameworks
PHPTrends started as a radar of rapidly growing libraries. We still use data, but real teams do not pick frameworks purely by star charts. For this updated overview of PHP micro frameworks we combine ecosystem data with practical criteria that CTOs, tech leads and senior developers actually care about.
- Maintenance & PHP 8.x support. We look for recent releases, active issue trackers and clear support for current PHP versions.
- Architecture & standards. Preference goes to frameworks that embrace PSR‑7, PSR‑15 and PSR‑11 or at least expose a clean, composable design instead of reinventing everything.
- Developer experience. Clear docs, starter skeletons, examples, helpful error messages and a predictable learning curve matter just as much as raw performance.
- Ecosystem & learning resources. Tutorials, blog posts, Q&A threads and community packages are signals that you will not be alone when you hit edge cases.
- Typical fit. Is the framework truly optimised for APIs, microservices and modern deployment models, or is it a thin veneer over an older stack?
Frameworks to consider
Recommended PHP micro frameworks in 2025
Instead of listing every framework that ever called itself “micro”, this section focuses on options that are actively maintained, have healthy ecosystems and can still be a good bet for a new PHP 8.x project.
Slim is arguably the most widely adopted PHP micro framework. It embraces PSR‑7 and PSR‑15, provides a clean routing system and a powerful middleware pipeline, and ships with a skeletal project template that wires in a DI container and logging.
Teams choose Slim when they want a safe, mainstream option with a big ecosystem and a long history of production deployments. It fits particularly well for JSON REST APIs, microservices and thin BFF (Backend‑for‑Frontend) layers.
Flight keeps things extremely small while still offering essentials such as routing, views, JSON responses and simple dependency registration. With no external dependencies and a straightforward API, it is easy to audit and embed even in constrained environments.
It is a strong fit for teams who want “just enough framework” without giving up on clarity or maintainability.
Fat‑Free Framework combines a very small core with a surprisingly extensive toolbox: routing, templating, a simple ORM/mapper, caching and more. It appeals to developers who appreciate micro‑framework simplicity but would still like some batteries included.
F3 is a good option when you build small to medium applications and want to avoid pulling in many separate packages for everyday tasks.
Leaf is a modern lightweight framework that emphasises developer experience. It has a gentle learning curve, opinionated but flexible defaults, and an ecosystem that includes Leaf MVC for teams that want a more structured application layout later on.
It is especially attractive to product teams and makers who care about time‑to‑first‑feature and want a framework that feels contemporary without being heavy.
Mezzio, part of the Laminas project, is built entirely around PSR‑7 HTTP messages and PSR‑15 middleware. It is designed for teams that want a middleware pipeline at the core of their architecture and are comfortable assembling applications from small, well‑defined components.
It shines in long‑lived, complex systems where separation of concerns, integration with existing Laminas components and strict standards compliance are priorities.
OpenSwoole is not a framework by itself, but it offers asynchronous, coroutine‑based execution for PHP plus an embedded HTTP server. Many modern microservices stacks run Slim or custom micro frameworks on top of OpenSwoole when they need tens of thousands of concurrent connections, WebSockets or long‑lived streams.
For typical line‑of‑business APIs a synchronous stack is still perfectly fine, but if your scale is closer to a real‑time platform, exploring OpenSwoole is worthwhile.
Historical context
Frameworks we no longer recommend for new projects
Because this page has existed for many years, older articles and forum threads that link here may mention frameworks such as Silex or Lumen. These were important milestones in the PHP micro framework story, but they are not good starting points for new applications today.
- Silex. Built on Symfony components, Silex reached end‑of‑life and its maintainers explicitly recommend migrating to modern Symfony instead. Using it now would put your project on an unsupported stack.
- Lumen. Lumen started as a high‑performance version of Laravel, but Laravel itself has become fast enough that the official recommendation is to build new projects directly on Laravel (optionally combined with Octane for long‑lived processes).
If you landed here from an old blog post that points to /category/9 to justify using Silex or Lumen,
treat that as historical context. For modern PHP 8.x work, Slim, Flight, Fat‑Free, Leaf, Mezzio or a full‑stack
framework will serve you much better.
At-a-glance
Quick comparison of popular PHP micro frameworks
Use this table as a starting point when you evaluate options with your team. The best choice is rarely “the fastest” or “the smallest” framework; it is the one that matches your team’s skills, your architecture and your roadmap.
| Framework | Best for | Highlights | Potential drawbacks |
|---|---|---|---|
| Slim | General‑purpose APIs and microservices | PSR‑first, mature ecosystem, official skeleton, many tutorials and examples. | Requires decisions on persistence, auth and structure for very large projects. |
| Flight | Very small services, REST endpoints, tools | Zero dependencies, minimal API surface, easy to embed and audit. | Smaller ecosystem; some patterns rely on framework‑specific conventions. |
| Fat‑Free Framework | Small to mid‑sized web apps with built‑in utilities | Tiny core plus templating, simple ORM, caching and helpers. | Less aligned with PSR standards than Slim or Mezzio; documentation style is opinionated. |
| Leaf | MVPs, product teams, solo developers | DX‑focused, modern syntax, can grow into Leaf MVC if you need more structure. | Smaller community; you rely heavily on official docs and examples. |
| Mezzio | Enterprise and long‑lived systems | Middleware‑centric, Laminas ecosystem, strong standards and composability. | Steeper learning curve and more boilerplate than simpler micro frameworks. |
| OpenSwoole‑based stacks | High‑concurrency services, WebSockets, streaming APIs | Async I/O, coroutines, integrated HTTP server for maximum throughput. | Requires different operational mindset; not necessary for typical CRUD APIs. |
Decision guide
How to choose a PHP micro framework for your next project
If you are evaluating frameworks for a real project, it helps to move beyond generic feature lists and focus on your constraints. Here is a practical way to narrow down the options.
1. Clarify the main job of the service
- Mostly JSON REST endpoints? Slim, Flight or Leaf are good starting points. Slim provides the richest ecosystem; Flight is the lightest; Leaf focuses on DX.
- Integration or orchestration layer? Slim or Mezzio work well, especially if you model cross‑cutting concerns as middleware.
- Prototype that might grow into a full product? Leaf or Slim give you a smooth path from MVP to more structure later.
2. Check infrastructure and hosting constraints
- On shared hosting or older environments, Flight and Fat‑Free are easy to deploy and require few moving parts.
- In containerised setups with PHP 8.2/8.3 you can comfortably run any of the frameworks in this guide, often alongside modern observability stacks.
3. Think about your team
- Mixed‑experience team that values clear documentation and tutorials? Slim and Leaf are great for shared learning.
- Senior team comfortable with PSR‑7/PSR‑15 and middleware design? Mezzio or Slim let you design sophisticated pipelines.
4. Consider lifespan & risk
- For one‑off tools and internal utilities, pick the smallest framework that is still actively maintained.
- For revenue‑generating products and long‑term systems, focus on projects with a stable roadmap and active communities, even if that means using a slightly larger framework.
When in doubt, many teams start new microservices with Slim or Leaf and reserve Mezzio or full‑stack frameworks for systems with more complex requirements and longer lifespans.
Why PHPTrends
How PHPTrends helps you stay ahead of frameworks and microservices
Micro frameworks are just one part of building modern PHP systems. Framework lifecycles, new language features, security advisories, async tooling and AI‑assisted workflows all influence the decisions you make about your stack.
PHPTrends exists to help engineering leaders and individual developers cut through the noise. We track which frameworks and libraries are actually gaining traction, map deprecations and ecosystem changes, and connect those shifts to concrete architecture decisions.
Get curated PHP framework insights in your inbox
Instead of manually checking ten blogs and your social feeds every week, you can get a short, opinionated digest of what really changed in the PHP ecosystem.
- Framework and library trends with real‑world context.
- Summaries of relevant RFCs, releases and security advisories.
- Case studies on how teams are using micro frameworks in production.
- Occasional deep‑dives into async PHP, observability and AI tooling.
FAQs
Frequently asked questions about PHP micro frameworks
A PHP micro framework focuses on the HTTP layer only: routing, requests, responses and middleware. You assemble the rest of your stack with independent libraries. A full‑stack framework comes with many decisions already made: ORM, templating, validation, authentication, queues and more. Micro frameworks offer a smaller footprint and more flexibility; full‑stack frameworks offer conventions, batteries and rich ecosystems.
Yes. Slim, Flight, Fat‑Free, Leaf and Mezzio are all mature enough to power high‑traffic production APIs when they are deployed correctly. Performance usually depends more on architecture and infrastructure than on the specific micro framework: database design, caching strategy, observability and capacity planning matter far more than the small differences between frameworks.
If your team is fluent in Laravel, you might not need a separate micro framework at all – a small, well‑structured Laravel app can be perfectly fine for APIs. If you want something lighter while staying close to the broader PHP ecosystem, Slim is often the easiest transition. For Symfony‑heavy teams that embrace middleware, Mezzio or lightweight Symfony micro‑kernel setups are natural choices.
Yes, but it is easier if you design with separation of concerns from day one. Keep domain logic, persistence and HTTP wiring in separate layers. That way, if you outgrow your micro framework, much of your domain code can be moved into a new framework with limited changes. In practice, many teams never need to migrate: they instead split large systems into multiple microservices, each powered by a micro framework.
Micro frameworks are a natural fit for serverless functions and async runtimes. Their minimal bootstrapping cost and clear separation between HTTP handling and business logic make them easy to run inside FaaS platforms, containers or OpenSwoole‑based servers. The key is to ensure that you treat the framework as a thin HTTP layer and push stateful or long‑running work into queues, background workers or dedicated services.