Hire The Top 1% Freelance PHP Developers

Flexiple is a network of top PHP developers, engineers, and architects with hourly rates ranging from $30 to $100. Join 100+ teams who have hired PHP developers from Flexiple for a few weeks to a few years!

Flexiple spent good amount of time understanding our requirements, resulting in accurate recommendations and quick ramp up by quality developers.

Narayan Vyas, Senior PM (YC S12)

Overall Flexiple brought in high-level of transparency with quick turnarounds in the hiring process at a significantly lower cost than any alternate options.

Esther Hersh, Co-founder ('17 NYU Grad)

Flexiple has been instrumental in helping us grow at a fast pace. Their vetting process for engineers is top notch and they connected us with quality talent quickly.

Tanu V, Founder (#1 Salesforce Leads App)

Work With Flexiple's Expert PHP Developers!

Be a short-term or a long-term project, don't compromise on the quality of talent you work with. Flexiple handpicks only the Top 1% through a 6-stage screening process.
  • Otsuka Endo, freelance php developer
    Otsuka Endo
    PHP React Python

    A senior full-stack engineer, Otsuka has 8 years of experience across technologies such as ReactJS, VueJS, NodeJS, Django, and Laravel. He has worked with ... several companies across the world as a freelance PHP engineer in an agile environment on both small and large scale projects. Over the last 6 months, he has been working as a remote freelancer with a US-based startup. Read more

    Previously at Fujisoft

    Hire Otsuka
  • Aditya Vinnakota, freelance php developer
    Aditya Vinnakota
    PHP Python Angular

    A senior developer with ~16 years of experience, Aditya has worked both as an individual contributor and a team lead for multiple startups. Over the ... course of his career, he has developed solid expertise in many application development and Big Data technologies. Also, he’s an experienced freelancer who has worked on Python, NodeJS, MySQL, AWS and PHP freelance projects successfully. Read more

    Previously at Edavantics

    Hire Aditya
  • Lucas Marques Rosa, freelance php developer
    Lucas Marques Rosa
    React Vue PHP

    Lucas, with 8+ years of experience, typically works as a front-end engineer but also has a full-stack background. He has freelanced on projects built on PHP, HTML, ... CSS, ReactJS, and VueJS technologies. He has worked on real-time applications serving more than 200,000 users with a number of service and product-based companies. Lucas is also well versed in creating scalable products across multiple domains including gaming, e-commerce, consultancies, etc. Read more

    Previously at Twiser

    Hire Lucas
  • Prashant Chaudhary, freelance php developer
    Prashant Chaudhary
    PHP Angular iOS

    A 2010 IIT-Delhi grad, Prashant is a senior software developer with 8+ years of experience. His experience ranges from building fairly complex web apps ... using Angular 2+ & Laravel as well as building native mobile apps for iOS & Android in the respective technologies and in Flutter. After taking up freelancing, Prashant has worked on many challenging freelance PHP, Angular, Android projects, etc. Read more

    Previously at Vaetas LLC

    Hire Prashant
  • Andrei Statescu, freelance php developer
    Andrei Statescu
    Java Ruby on Rails PHP

    Andrei, a full-stack developer, has 5+ years of industry experience. He is an ex-Microsoft software engineer and has worked on multiple freelance projects on ... PHP, JavaScript, .NET, Java, Android, etc. Andrei loves to tackle complex tasks, especially those involving large data and complex algorithms. Furthermore, his entrepreneurial spirit has led him to start his own firm, which is a platform for his freelance work. Read more

    Previously at Microsoft

    Hire Andrei
  • Muthu Subramanian, freelance php developer
    Muthu Subramanian
    PHP Android Angular

    Muthu, a full-stack developer, has over 15 years of experience in the software development space. He is a well-articulated technocrat, who is skilled in multiple technologies ... and worked on a number of freelance PHP, AngularJS, Android, iOS, and Python projects. Apart from entrepreneurial experience, Muthu has worked with top product companies such as Amazon and Ericsson and is technically strong. One of his top projects includes working on Amazon Prime’s backend development work. Read more

    Previously at Amazon

    Hire Muthu
  • Rex Varghese, freelance php developer
    Rex Varghese
    PHP Android NodeJS

    Rex, an experienced software consultant, has a demonstrated history of working in the computer software industry for 15+ years. He has a diverse portfolio ... that includes projects with various companies as well as independent projects. Rex is well versed and has freelanced many projects on PHP MVC Framework, with backend design and development, database design and programming, API design and development, mobile application development, and Javascript cloud server management among others. Read more

    Previously at DQS NXT

    Hire Rex
  • Bala Narayanan, freelance php developer
    Bala Narayanan
    PHP Node

    A seasoned and versatile professional with over 10+ years of experience in the software industry, Bala has an entrepreneurial mindset with meticulous attention ... to detail and the ability to decouple and re-engineer existing applications. He is an avid programmer with a flair for technical management and aptitude to learn new technologies. Also, over more than 6+ years, Bala has worked on NodeJS, Angular, AWS and PHP freelance projects. Read more

    Previously at Infosys

    Hire Bala

Flexiple Helps You Hire Quality Developers, Handpicked for You

  • Work only with the best

    Our developers are selected through a 6-stage screening process. As a result, our developers have an average of 5-years industry experience and are ready to immediately contribute on projects.
  • Work with Role-specific Developers

    Save time and energy lost in manually sifting through profiles. Our solutions expert along with our Director of Technology will handpick developers who are a perfect match for your requirement.
  • Work Risk-free & Start within 2 Days

    With immense confidence in the quality of our developers and the accuracy of our recommendations, we are happy to offer you a 1-week trial where you pay only if you are satisfied.

Find the perfect developer for your team at the right price

  • Individual Contributor

    $
    /year
    $30-50
    /hour
    • 1-3 years of experience
    • Mostly worked on a single stack
    • Top Individual Contributor
  • Multi-faceted Contributor

    $
    /year
    $50-80
    /hour
    • 3-7 years of experience
    • Expertise in multiple stacks
    • Worked on niche skills
    • Mentors Junior Developers
  • Leader & Diverse Contributor

    $
    /year
    $80+
    /hour
    • 7-10+ years of experience
    • Works across tech stacks
    • Multiple niche skills
    • Led multiple teams in the past

How We Select the Top 1%

45.4%pass rate

Depth in past work

Flexiple Developers are reviewed on their experience and complexity of products built. Those who display depth and have worked on end-to-end projects are given an introductory call.

14.6%pass rate

Good communication and motivation

Over a call, the developer’s ability to communicate in an articulate manner is tested. A deeper understanding of the candidate’s technical experience and also motivation to freelance is achieved.

3.1%pass rate

Strong technical abilities

Over one or more F2F interviews, the developer’s involvement and performance in building complex software products are assessed. This sets the platform to delve deeper into technology-specific discussions.

1.5%pass rate

Keen problem solving and coding

Developers' mental agility and problem-solving abilities are tested through a coding test involving algorithmic as well as skill-specific problems. A mixture of live evaluation and timed coding tests is used.

1.2%pass rate

Splendid reviews in background check

The live experience of working with developers is verified by reaching out to past clients and/or employers. Inputs on various qualitative factors such as reliability, punctuality, communication and responsiveness are received.

1%pass rate

Consistent exemplary performance

Performance during each engagement is continually assessed. Our developers are expected to maintain Flexiple standards across all engagements with our customers.

Don't Just Take Our Word For It!

(Y-Combinator S12 and Andreessen Horowitz-backed Company)

Quality product launched on schedule by a team of 8 engineers

"Flexiple helped us hire quality developers across technologies - Node, Rails, PHP, Python. They spent a good amount of time understanding our requirements, resulting in accurate recommendations and quick ramp up by developers. We also found them to be much more affordable than other alternatives for the same level of quality."

Narayan Vyas,

Senior Product manager, Plivo Inc

(Incubated at the European Space Agency)

Helped set up and scale tech team on demand

"Flexiple has exceeded our expectations with their focus on customer satisfaction! The freelancers are brilliant at what they do and have made an immense impact. Highly recommended :)"

Henning Grimm,

Founder, Aquaplot

(Acquired by Unicorn, Hike Messenger)

Saved 30% costs with 2 software products delivered

“Overall Flexiple brought in high-level of transparency with extremely quick turnarounds in the hiring process at a significantly lower cost than any alternate options we had considered.”

Kislay Shashwat,

VP Finance, CREO

('17 NYU Graduates)

Found a perfect new member for its globally distributed team

"Working with Flexiple has provided us with partners who are providing us with the required technical support for our growth and success!"

Esther Hersh,

Co-founder, Peblio Inc

(Y-Combinator S18)

Hired the first remote engineer to work directly with the CTO

"It has been great working with Flexiple for hiring highly talented and hardworking folks on contract. We were looking for a suitable developer on the back-end and we got to know Ankur through Flexiple. We are very happy with the commitment and skills he brings to the job and we will be working with Flexiple going forward as well after this positive experience. I recommend them highly for any freelancing talent you are looking to hire!"

Neil Shah,

Chief of Staff, Prodigal Tech

(#1 Lead Routing App for Salesforce)

Helped scale the product with a team of engineers

"Flexiple has been instrumental in helping us grow at a fast pace. Their vetting process for engineers is top notch and they were able to connect us with quality talent quickly. The team put great emphasis in understanding our requirements and getting to know us which ensured that we were matched with folks who were a great fit not only technically but also culturally."

Tanu V,

Founder, Power Router

(Acquired by Reliance for $100 million)

Delivered 2 high quality products forming a long partnership

"The engagement with Flexiple and their community members has helped us get work done in a timely manner and helped us go above and beyond."

Swapan R,

Co-founder, Haptik

(Acquired by PayU for $70 million)

Built their first remote tech team of a frontend and backend engineer

"Highly responsive team with prompt support and willingness to go the extra mile. Powered by technically brilliant personnel on board, we have happy results – all this at an affordable price!"

Sajith N,

Product Manager, Wibmo Inc
  • How to Hire a Great Freelance PHP Developer?


    Looking for a freelance PHP developer but not sure about how to hire the perfect fit? Well, according to Daxx, there are 5.5 million PHP developers across the globe as of September 2018. That's a pretty significant number, isn't it? Finding the right developer for you in such a large number is a serious task. That's where this guide helps you out - it has everything you need to know about hiring a freelance PHP developer.

    We have broken the sections into the following parts:
    1. Let's introduce PHP to you
    2. Why is PHP widespread?
    3. Writing the Job Description
    4. Interview Questions for hiring a PHP developer
    - Basic Questions
    - Advanced Questions
    - Data Structures/Algo Questions


    1. Let's introduce PHP to you

    Before diving into the fundamentals of hiring a freelance PHP developer, let's delve into some interesting facts about the history of PHP.

    • Origin story: Back in 1994, Rasmus Lerdorf used CGI binaries in C language to track visits on his online resume which brought into being a widely used scripting language that we all know of as PHP which is short for PHP: Hypertext Preprocessor.

    • Widely popular: According to W3Tech’s data, PHP is used by 79% of the websites whose server-side programming language is known.

    • Used by top tech companies: Top brands like Facebook, WordPress, Slack, Flickr, Yahoo, and TED are powered by PHP.

    • Other trivia: PHP has a mascot - a big blue elephant named elePHPant. Vincent Pontier, who came up with the design said in an interview that the idea of an elephant came very naturally as he drew the PHP letters on paper and played with them a little - he noticed that they form a shape of an elephant.

    • 2. Why is PHP widespread?

      Two features make PHP a great choice vs. other languages. They are:

      • Easy to integrate with other technologies such as Java- does not require re-development.
      • Ability to fix errors quickly, making it easy to maintain.
      Further, PHP is considered to be a comparatively easy language to learn. This attracts newbies, who can make dynamic websites with minimum programming expertise. However, this also makes hiring a great PHP developer challenging.


      3. Writing the Job Description

      Below are some key points that we at Flexiple have learned through trial and error - a process of filtering through over 15,000 developers.

      • Years of software development experience: Be specific about the number of years of experience needed and the technology you’re looking for. A proxy to years of experience can be the number of production-level apps worked on.

      • Expertise in particular PHP frameworks/versions: Each PHP framework has its peculiarities and nuances. While good PHP developers can pick up other frameworks, it’s a plus point to hire a developer who already has expertise in it.

      • Type of products built in the past: You can filter out applications based on the candidate’s past work if you want someone who has a fair idea about how things work in a product like yours.

      • Exposure to certain industries: Developers who have built products in certain industries will already know key aspects of laying the foundation for a great product and will be able to predict possible problems.

      • Experience working remotely: Hiring someone who has worked remotely in the past is an added benefit as they have front-hand experience of everything right from how the contracts work to communication and from timelines to deliverables.

      • Strong communication: An essential thing to look at when hiring a freelancer is good communication skills. Since all the communication happens online, a freelancer needs to be able to seek to understand and be direct in their language.

      • 4. Interview Questions for hiring a PHP developer

        Now that you have made a quality JD, it can still be tricky to evaluate the skills of your applicants. To help you with that, we have created a pool of questions that a good PHP developer should be comfortable with.
        It is important to note that the ability to answer these questions doesn't imply that you have a top quality candidate. But it definitely is a big step in that direction.

        To help you navigate through these questions, we’ve categorized the interview questions in 3 parts:

        A. Basic concepts: Includes all basic concepts used across languages but we've focused on their significance in PHP. This will give you an understanding of how strong their programming foundation is.

        B. Advanced concepts: Includes all concepts that someone with higher expertise should know.

        C. DS/Algorithm questions: To test the logical capability of the candidate.


        A. Basic concepts

  • What are the magic methods in PHP? List 5 magic methods and explain each with an example.

    Magic methods are methods that are automatically triggered in response to a particular PHP event.
    To invoke any user-defined function in PHP, you need to make a function call. A magic method is special since it doesn’t require an explicit function call. It is invoked automatically when an event is triggered.

    Rules of function definition of a magic method:
    • 1. The method name must begin with 2 underscores (__).
    • 2. The method should be defined inside the class.
    • 3. The method should be declared public.

    PHP magic methods invoked on creating a class instance are:

    __construct()
    This method is called when an object is instantiated. The purpose of the construct() method is to assign some default values to object properties. In the OOPS paradigm, this is the parallel for a constructor. Typically, this should be the first thing in your class declaration. However, just like any other method, you can choose to declare it anywhere in the class body.

    Example:

    class Employee{
        private $name;
        private $email;
    
        public function __construct($name, $email)
        {
            $this->name = $name;
            $this->email = $email;
        }
    }
    
    $objEmployee = new Employee('Sam', ‘sam@robustplus.com');
    

    In the above example, when a new employee is instantiated with name- Sam and email- sam@robustplus.com, the magic method construct is called. The __construct() method assigns values passed in the arguments to the respective object properties.

    __destruct()
    This method is called when the object is destroyed or no longer has any references either by PHP itself or explicitly by the user. It could also be called when the script stops or is exited.

    Example:

    class Employee{
        private $name;
        private $email;
    
        public function __construct($name, $email)
        {
            $this->name = $name;
            $this->email = $email;
        }
    
        public function __destruct()
        {
            echo 'This will be called when the script stops.';
        }
    }
    
    $objEmployee = new Employee('Sam', ‘sam@robustplus.com');
    

    PHP magic methods used to deal with inaccessible class members created at runtime by the concept of PHP overloading.

    __get($property)
    This method is called when you try to read data from inaccessible or non-existent object properties. This method helps you to get values for such dynamic object properties.

    Example:

     class Employee{
        private $data = array();
    
        public function __set($name, $value)
        {
            $this->data[$name] = $value;
        }
    
        public function __get($name)
        {
            If (isset($this->data[$name])) {
                return $this->data[$name];
            }
        }
    }
    
    $objEmployee = new Employee();
    echo $objEmployee>phone;            // __get is called
    


    __set($property, $value)
    This method is called when you try to set data to inaccessible or non-existent object properties. This method helps you to get values for such dynamic object properties.

    Example:

    class Employee{
        private $data = array();
    
        public function __set($name, $value)
        {
            $this->data[$name] = $value;
        }
    
        public function __get($name)
        {
            If (isset($this->data[$name])) {
                return $this->data[$name];
            }
        }
    }
    
    $objEmployee = new Employee();
    $objEmployee>phone = '5879584623';              // __set is called
     


    __isset($content)
    This method is called when a call to the isset() method is made on inaccessible or non-existent object properties. In simpler terms, it is invoked automatically while checking whether a required overloaded property is set or not.

    Example:

     class Employee{
        private $data = array();
    
        public function __isset($name)
        {
            return isset($this->data[$name]);
        }
    }
    $objEmployee = new Employee();
    echo isset($objEmployee>phone);
    

  • What is the purpose of $GLOBALS & $_SERVER variables in PHP?

    $GLOBALS & $_SERVER variables are PHP superglobals. Superglobals are specially-defined array variables used to get or store information from the different pages of an application. These variables can be accessed at all times regardless of scope from any function, class, or file.
    PHP has 3 variable scopes - local, global, and static.
    • Local - Any variable defined inside a function has a local scope and can only be accessed inside the function.
    • Global - A variable declared outside the function has a global scope and can be accessed outside the function, But, using the 'global' keyword, you can access any global variable inside a function.
    • Static - PHP deletes all variables after the function is executed. The variable must be declared static if its value needs to be used after function execution.
    Example: of accessing a global variable inside a function:

    $x = 10;  //global scope
    $y = 12;
           function add() {
              global $x, $y;
              $y = $x + $y;
           }
    addt();
    echo $y;        // outputs 22
    

    Another way of doing the same would be using the $GLOBALS superglobal.

    $GLOBALS is used to access global variables from anywhere in the script. PHP stores all the global variables in an array called $GLOBALS[]. To access a particular global variable you must pass the variable name as an index to the array. ($GLOBALS[index~name])

    Considering the same example:

    $x = 10;
    $y = 12;
    function multiply(){
        $GLOBALS['z'] = $GLOBALS['x'] * $GLOBALS['y'];
    }
    multiply();
    echo $z; 
    

    In the code above, $x and $y are global variables holding values 10 and 12 respectively. A function multiply() performs a multiplication operation on the two global variables using the $GLOBALS[] to output 120.

    The $_SERVER superglobal stores information about the headers, paths, and script locations.
    Some important elements that the $_SERVER variable holds are:

    1. $_SERVER['PHP_SELF']- returns the filename of the current script
    2. $_SERVER['GATEWAY_INTERFACE']- returns the CGI version
    3. $_SERVER['SERVER_ADDR']- returns the host server’s IP address
    4. $_SERVER['SERVER_NAME']- returns the host server name
    5. $_SERVER['REQUEST_METHOD']- returns the request method used. Example- POST or GET.
    6. $_SERVER['REQUEST_TIME']- returns the request start time in timestamp
    7. $_SERVER['HTTP_HOST']- returns the host header of  the current request
    8. $_SERVER['SCRIPT_NAME']- returns the path of the current script
    9. $_SERVER['SERVER_PORT']- returns the port being used for communication
    10. $_SERVER['REMOTE_ADDR']- returns the IP address of the user viewing the current page

    Example:

    echo $_SERVER['SERVER_NAME'];
    echo $_SERVER['SCRIPT_NAME'];
    

    The output for the above code snippet is :
    localhost
    /demodoc/demo_global_server.php 
  • What are the methods used to collect form data after the form is submitted to the server in PHP? Can you submit a form without a submit button? If yes, give 2 examples and also mention how would you verify if the form is successfully submitted?

    The GET and POST methods are used to collect form data after the form is submitted to the server. They’re both treated as superglobals and hence are accessible at all times($_GET & $_POST). Both, GET and POST create an array that holds key/value pairs, where the key is the name of the form control and value is the input data from the user.

    The basic difference between the two is that the $_GET variables are passed to the current script via URL parameters and $_POST variables are passed via the HTTP POST method.

    The GET method is not advised when you need to send important information like a password because the information sent via the GET method is visible to everyone as opposed to that of the POST method that goes via the headers of the HTTP POST method and remains invisible to others.
    The POST method has no limits on the characters passed but the GET method is limited to approximately 2000 characters only.

    Here’s an example of a simple form using the post method:
    When the submit button is clicked, the data inside name and email input fields are sent via the HTTP POST method to a PHP file.

    Hi <?php echo $_POST["name"]; ?>
    Your email address is: <?php echo $_POST["email"]; >

    The output of the above snippet will be:
    Welcome Sam
    Your email address is: sam@robustplus.com

    To achieve the same with $_GET, change the method to ‘get’:

    <form action="reg.php" method="get">
    Name: <input type="text" name="name">
    Email: <input type="text" name="email">
    

    #reg.php

    Hi <?php echo $_GET["name"]; ?>
    Your email address is <?php echo $_GET["email"]; ?>

    The output then be:
    Hi Sam
    Your email address is sam@robustplus.com.

    And the URL will be

    localhost/reg.php?name=Sam&email=sam%robustplus.com

    Yes, a form can be submitted without the submit button. The most commonly used ways of doing it are:

    A. Submit a form by clicking on a link using the onclick() method:

    <a href="#" onclick="document.getElementById('submit').submit(); >
    where 'submit' is the form ID.

    B. Submit by selecting an option from the drop-down menu on change:

    $('#theme').change(function(){
    $('form').submit();
    });
    where ‘theme’ is the id of <select>

    The isset() method is used to check if the form has been successfully submitted.

    if (isset($_POST['submit'])) {
        echo "Successful submission";
    }
    where ‘submit’ is the button name.

    B. Advanced concepts

  • What are traits in PHP? What are the keywords used to declare and use traits? Explain with an example.

    PHP doesn’t support multiple inheritances. The ‘extends’ keyword is used to perform a single class inheritance. Traits were introduced in PHP 5.4 to provide multiple inheritances. In a nutshell, traits are used to declare methods that can be used in multiple classes. These methods also include abstract methods with any access modifier- public, private, or protected.

    Traits are similar to classes but they are used for grouping methods consistently and unlike a class, they can’t be instantiated on their own.

    The 'trait’ keyword is used to declare traits:

    trait Trait1{
      //code
    }
    And the use’ keyword is used to use a trait in a class:

    class MyClass {
    use Trait1;
    }

    Example:

    Let’s create a library.php file and create a class library

    class Library{
         public function student(){
              echo "I am student A";
          }
    }

    Now, let’s create another file index.php and create a class book and extend it to Library

    require_once 'Library.php';
    class Book extends Library{
    }
    $obj = new Book;
    $obj->student();
    When we run index.php it will output ‘I am student A’ but what if Book comes with a new feature of having an ebook version?
    Let’s create a new file for ebook.php

    class Ebook{
       public function version(){
         echo '1.0’;
       }
    }
    Now, if I want to inherit Book in the index.php file- I can’t do it because it already extends Library.
    This is where I can use traits. All I have to do is convert the class to a trait like:

    trait Ebook{
     public function version(){
       echo '1.0’;
      }
    }
    Now to make the methods in Ebook available in Index- I need to add ebook in index.php>

    require_once ‘Library.php';
    require_once ‘Ebook.php';
       class Book extends Library{
         use Ebook;
        }
    $obj = new Book;
    // now I can use methods inside trait Ebook
    $obj->version(); //and methods from library
    $obj->student();
    I can also use 2 traits together. Let's assume I have another trait Price with a function range.

    Index.php:

    require_once ‘Library.php';
    require_once ‘Ebook.php'; 
    require_once ‘Price.php'; 
    
       class Book extends Library{ 
           use Ebook, Price; 
       } 
    $obj = new Book;
    // now I can use methods inside trait Price
    $obj->range(); 
    // now I can use methods inside trait Ebook
    $obj->version(); 
    // and method from Library
    $obj->student();
    If you have 2 traits with the same method name range. PHP will throw a fatal error but it can be fixed using the ‘insteadof’ keyword.

    Ebook::range insteadof Price;
    //Or pass it as an alias:
    Price::range as Prange; 
  • How are objects created in PHP? Why and how are the keywords $this and $instancof used? Explain with examples.

    Objects are individual instances of the data structure defined by a class. We can make multiple objects from a class. Each object inherits all the properties and methods defined in the class but has different property values.
    Objects of a class are created using the new keyword.

    Example:

    class Colors{}
    $yellow = new Colors;
    $orange = new Colors; 

    Objects are also called instances. Once you’ve created the objects, you can use parent class methods on them.

    class Colors{
    function set_name($name) {
        $this->name = $name;
      }
    function get_name() {
        return $this->name;
      }
    }
    $yellow = new Colors;
    $yellow>set_name('light');
    echo $yellow>get_name();
    The $this keyword maps to the current object and allows you to make changes to object values inside the method.

    Example:

    class Colors{ public $shade; }
    $yellow = new Colors;

    If I want to change the value of $shade, I can create a method set_shade() and use the $this keyword inside the class like:

    class Colors{
      public $shade;
          function set_shade($name) {
             $this->shade = $shade;
           }
       }
    $yellow = new Colors();
    $yellow>set_shade("Light Yellow");

    Or I can do it outside the class directly:

    class Colors{
      public $shade;
    }
    $yellow = new Colors();
    $yellow>shade = "Light Yellow";
    The $instanceof keyword is used to check if an object belongs to a specific class.

    Example:

    $yellow = new Colors();
    var_dump($yellow instanceof Colors);
    The output will be bool(true). 
  • What are the types of arrays supported in PHP? What is an array filter? List 3 different ways of sorting arrays in PHP.

    An array is a data structure that can hold many values of similar data types under a single name. Individual array values are accessed via an array index which starts with 0.

    PHP supports 3 types of arrays:

    1. Indexed arrays have a numeric index and the stored values are accessed linearly.
    Example: To store values:

    $colors = array("Red", "Yellow", "Oange"); 
    To access the stored values:

    echo "I like " . $colors[0] . ", " . $colors[1] . " and " . $colors[2] . "."; 

    2. Associative arrays have strings indexes. Array values are stored in key-value pairs.
    Example: To store values:

    $rgb = array("R"=>"35", "G"=>"37", "B"=>"43"); 
    To access the stored values:

    echo "The R-value is " . $rgb[R] ;
    3. A multidimensional array is an array of arrays. The dimension of an array indicates the number of indices needed to map an element. For example, a two-dimensional array needs two indices to select an element, a three-dimensional array needs three, and so on.
    Example of a two-dimensional array: Consider we are storing the age and job experience in years for every candidate.
    The declaration will look something like this:

    $candidate = array (
      array("A",22,2),
      array("B",15,3),
      array("C",5,1)
    );
    And to access the information stored for candidate B,

    echo $candidate[1][0].": Age: ".$candidate[1][1].", Experience: ".$candidate[1][2].".";
    array_filter() is a built-in PHP function to filter the elements of an array using a callback function. array_filter() iterates through each value in the array and passes it to the callback function. If the callback function returns true, the current array value is returned else preserved.

    Syntax:
    array array_filter($array(mandatory), $callback_function(optional), $flag(optional))

    Parameters:
    1. $array-> refers to the input array which needs to be filtered
    2. $callback_function-> refers to the user-defined function. If none is passed, all values equal to FALSE are removed from the input array.
    3. $flag-> refers to the arguments passed in the callback function.
    Returns a filtered array.

    Example: to get even numbers :

    function Even($array)
    {
    	if($array%2==0)
    	    return TRUE;
    	else
    	    return FALSE;
    }
    $array = array(12, 0, 1, 18, 25, 0, 46);
    print_r(array_filter($array, "Even"));
    Output: Array
    (
        [0] => 12
        [1] => 0
        [2] => 18
        [3] => 0
        [5] => 46
    )
    3 ways to sort arrays in PHP are:

    1. sort() - sorting the input array in ascending order
    Example:

    $colors = array("Red", "Yellow", "Oange"); 
    sort($colors); 
    Output- Orange Red Yellow 
    2. rsort() - sorting the input array in descending order
    Example:

    $colors = array("Red", "Yellow", "Oange"); 
    sort($colors);
    Output- Yellow Red Orange
    3. asort() - sort associative arrays in ascending order, according to the value. Example:

    $age = array("C"=>"20", "B"=>"07", "J"=>"43"); 
    asort($age);
    Output:
    Key=B, Value=07
    Key=C, Value=20
    Key=J, Value=43 
  • What are generators and how are they different from normal functions? How do they work in PHP? Can you send values to the generator? If yes, how? Explain with an example.

    Generators were introduced in PHP 5.5 and while they look like functions, they act like iterators. Generators nullify the complexity of implementing a class that implements the Iterator interface. They are similar to functions except that they don’t return a value but yield as many values as needed.

    Generators return an object that can be iterated over. This is an object of the internal Generator class that implements the Iterator interface. Generators use the keyword ‘yield’ instead of ‘return’. Unlike ‘return’, ‘yield’ does not remove the function from the stack- it rather saves its state so that the execution can be continued when it is called again. Although, the ‘return’ keyword can be used to terminate the execution. The main purpose of a generator is to save memory and speed up the execution.

    Example:

    function read_file($filename) {
        $file = fopen($filename, 'r');
        while (($line = fgets($file)) !== false) {
            yield $line;
        }
        fclose($file);
    }
    foreach (read_file(‘file_name’) as $line) {
    }
    In the above code, the generator function yields the lines of the file passed as and when needed. Each time a call is made, the generator resumes from where it left off. After all the lines are read, the generator terminates and the loop ends.

    Yes, the send() method is used to send values or commands to the generator. This method is used on the result of the yield expression. For example, telling the generator to stop the execution.

    Example:

    function numbers() {
        for ($i = 0; $i < 6; ++$i) {
            $cmd = (yield $i);
            if ($cmd == 'stop') {
            return; // exit the generator
            }
        }
    }
    $generator = numbers();
    foreach ($generator as $a) {
        if ($a == 4) {
            $generator->send('stop');
        }
        echo "{$a}";
    }
    In the above code, the generator will iterate till a is 4, output- 0 1 2 3 4 and terminate the execution. 
  • What is composition over inheritance? Where does PHP (as a language) implement this?

    Composition over inheritance in OOP is the principle that classes should achieve polymorphism by their composition (reusing code) rather than inheritance from a base or parent class.

    In OOP, there are two ways of achieving polymorphism- inheritance & composition. Inheritance is based on a parent-child relationship a.k.a the ‘Is-a’ relationship. It bases one class/object on another class/object retaining similar implementation. In simpler words, a subclass inherits all methods of its superclass. For example, a subclass ‘Cat’ inherits all traits of its superclass ‘Animal’.

    Composition, on the other hand, is the mechanism to reuse code across classes. The superclass is connected to the subclasses via a ‘has-a’ relationship.
    For example, a class ‘Car’ can be composed of an ‘Engine’ class as well as any other components to achieve a holistic functioning of the ‘Car’ class.

    While Composition is dynamic binding (run-time binding), Inheritance is static binding (-binding)

    To explain with an example composition over inheritance,

    class Vehicle
    {
        public function move()
        {
            echo "Move the car";
        }
    }
    class Car extends Vehicle
    {
        public function accelarate()
        {
         move();
        }
    $car = new Car();
    $car->accelerate();
    }
    In the above code snippet, there is a tight coupling(inheritance) between the classes- Vehicle and Car. Even the slightest change in the move() function in Vehicle class will cause the class Car to break. This can be solved using composition:

    class Vehicle
    { 
        public function move() 
        { 
            echo "Move the car"; 
        } 
    } 
    class Car 
    { 
        private $vehicle; 
        public function __construct(Vehicle $vehicle)
        { 
            $this->vehicle = $vehicle; 
        } 
        public function accelarate() 
        { 
            $this->vehicle->move(); 
        } 
    } 
    $vehicle = new Vehicle(); 
    $car = new Car($vehicle); 
    $car->accelarate();
    In this code snippet, passing the reference of class Vehicle into class Car’s constructor using dependency injection removes the tight coupling. The superclass and subclass are now independent of each other.
  • What is the factory pattern? How would you implement it in PHP?

    Design patterns in PHP act like blueprints that can be customized to solve a recurring software design problem. These patterns provide well tested, proven development/design paradigms that help to speed up the development process. Using design patterns, you can make your code more reusable, flexible, and maintainable.

    PHP has 3 design patterns-
    1. Creational patterns: These patterns are used to construct objects that can be decoupled from their implementing system.
    2. Structural patterns: These patterns are used to form object structures between many different objects
    3. Behavioral patterns: These patterns are used to manage relationships, algorithms, and responsibilities between objects.

    The Factory design pattern is one of the most used creational design patterns. It solves the problem of creating product objects without specifying their concrete class by maintaining a dedicated class responsible only for making objects. It is recommended to use the factory pattern when the subclass of an object instantiated can vary.

    Example:

    class Digital
    {
        private $mobileMake;
        private $mobileModel;
        public function __construct($make, $model)
        {
            $this->mobileMake = $make;
            $this->mobileModel = $model;
        }
        public function getMakeAndModel()
        {
            return $this->mobileMake . ' ' . $this->mobileModel;
        }
    }
    class DigitalFactory
    {
        public static function create($make, $model)
        {
            return new Digital($make, $model);
        }
    }
    
    $honor = DigitalFactory::create('Honor', '10 Lite');
    print_r($honor>getMakeAndModel()); // outputs "Honor 10 Lite"
    This code uses a 'DigitalFactory' to create a Digital object. The 2 benefits of doing this are:
    1. You can change, rename, or replace the Digital class whenever you need to- all you have to do is modify the code in the 'DigitalFactory', instead of every instance of the class in your project.
    2. Instead of creating a new instance every time you want to create an object- you can simply do all the work in the factory and reuse it.

    C. Data Structure/ Algorithm

  • Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order. Note that an empty string is also considered valid.

    function hasMatchedParenthesis($string) {
            $len = strlen($string);
            $string_check = 1;
            $stack = [];
            for ($i = 0; $i < $len; $i++) {
                switch ($string[$i]) {
                    case '(': array_push($stack, 0); 
                    break;
                    case ')':
                        if (array_pop($stack) !== 0)
                            return 0;
                    break;
                    case '[': array_push($stack, 1); 
                    break;
                    case ']':
                        if (array_pop($stack) !== 1)
                            return 0;
                    break;
                    case '{': array_push($stack, 1); break;
                    case '}':
                        if (array_pop($stack) !== 1)
                            return 0;
                    break;
                    default:
                           $string_check = 0 ;
                    break;
                }
            }
            return ($string_check ? empty($stack) : 0);
    }
    
    $result = hasMatchedParenthesis(")("); 
    echo $result;
    
    The above code will Output 0 (False). 
  • What will the output of the following code be?

    $x = 10;
    $y = 5;
    $z = 3;
    if ($x / $y / $z)
        print "hi";
    else
        print "hello"; 
    a) hi
    b) hello
    c) error
    d) no output

    The answer is A because the floating-point division in PHP returns a non zero value = 0.66 which evaluates to
    true and outputs ‘hi’.
  • What will the output of the following code be?

    $x = 2
    $y = 4
    $z = 6
    if($z > $y > $x) {
        echo “true”;
    }else{
        echo “false”;
    }
    The answer is False. It may look like the output can be true because 6 > 4 > 2 is true but PHP evaluates
    $z > $y first which returns a boolean value of 1 or true. This value (true or 1) is compared to the next integer
    in the chain, bool(1) > $z, which will result in NULL and echo “false.” 

    Parting thoughts


    Now that you know what to look for in a candidate when hiring a freelance PHP developer, the question is where to find these freelance developers? If you've been in the freelance industry for a while- you've probably heard of Toptal and are aware that it could be a little heavy on your pockets.

    You can find the best freelance PHP developers at Flexiple. Flexiple has already served over a hundred clients, earning great reviews for the quality of service but if you’re still not convinced- here’s why you should consider Flexiple. You can also take a look at our detailed article about the top alternatives for Toptal and pick one that suits you best.

    And there you have it- that's everything you need to know about hiring a freelance PHP developer. To quickly summarize it for you:
    1. Note your project requirements and hire accordingly. Do not go for the lowest or the highest-paid developer.
    2. Don’t hire without vetting- consider asking questions right from the basics to advanced to logical questions.
    3. Look for companies like Flexiple that help you find the perfect fit.

    Happy hiring! :)
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