Basic beginnings of a Toggl.com API version 8 PHP SDK. Currently only supports returning the logged in user, and submitting a new session to an existing workspace/project/task id. Other functions should be pretty easy to implement by copying the 'me' function for GET's, or the 'timeEntrySave' for POST's.

toggl_v8_sdk.php

<?php
/**
* Toggl v8 PHP SDK
* @author github.com/kythin (kythin@gmail.com)
* @version 1.0
* 
* Do-whatever-you-want-except-sell-it license, feel free to fork and improve! I think that means GPLv3 right?
* 
* I've gone through some of the examples in https://github.com/toggl/toggl_api_docs/tree/master/chapters (new v8 api docs)
* and implemented a handful of the ones I was using in old scripts, so check them out and if you add more support please
* somehow send it to me so I can update this for everyone else.
* 
* This should be considered to be very basic, still in development, and I can guarantee absolutely nothing. Contact me by all means, but
* please understand I don't offer any kind of promises to help you or to implement features or anything like that.
*/
class Toggl {
	
	public $userSecret;
	public $toggl_base_url = "https://www.toggl.com/api/v8";
	public $request;
	public $response;
	public $method = 'GET';
	public $endpoint;
	private $sdk_identifier = "PHP SDK for Toggl APIv8, by github.com/kythin";
 
//***********************************************************
// TOGGL SPECIFIC SHORTCUT FUNCTIONS
//***********************************************************
	
	
	public function me() {
		return $this->simpleGet('/me');
	}
	
	
	/**
	* timeEntrySave
	* $data should be a key indexed array based on the documentation for the POST /time_entries docs
	* https://github.com/toggl/toggl_api_docs/blob/master/chapters/time_entries.md
	*/
	public function timeEntrySave($data) {
		
		if (!is_array($data)) {
			die("timeEntrySave requires an array of data.");
		}
		
		if (!@$data['created_with']) {
			$data['created_with'] = $this->sdk_identifier;
		}
		
		return $this->simplePost('/time_entries', array('time_entry'=>$data),true,true);
	}
	
	
	//https://github.com/toggl/toggl_api_docs/blob/master/chapters/time_entries.md#start-a-time-entry
	public function timeEntryStart($data) {
		
		if (!is_array($data)) {
			die("timeEntrySave requires an array of data.");
		}
		
		if (!@$data['created_with']) {
			$data['created_with'] = $this->sdk_identifier;
		}
		
		return $this->simplePost('/time_entries/start', array('time_entry'=>$data),true,true);
	}
	
	
	//https://github.com/toggl/toggl_api_docs/blob/master/chapters/time_entries.md#stop-a-time-entry
	public function timeEntryStop($id) {
		return $this->simpleOther('PUT',"/time_entries/$id/stop",array(),true);
	}
	
	
	
	
	
	
	
	
	
//***********************************************************
// END OF TOGGL SPECIFIC SHORTCUT FUNCTIONS
//***********************************************************
	
	
	/**
    * __Construct
    */
    public function __construct($secret){
        $this->userSecret = $secret;
    }
	
	public function checkJSON() {
		if (!json_decode($this->response,TRUE)) {
			die("The server returned non-JSON string: ".print_r($this->response,true));
		}	
	}
	
	
    /**
     * simpleGet
     * Used when the action is a very simple dump of the data provided by the endpoint (most GET requests)
     * @return array
     */
    public function simpleGet($endpoint, $postargs = false, $decode = true) {
 
        //simply refresh the request and point it at the endpoint.
        $this->request = array();
        $this->method = 'GET';
        $this->endpoint = $endpoint;
 
        if ($postargs) {
            $this->request = $postargs;
        }
 
        if ($this->sendRequest($endpoint)) {
            //if it's successful, the response will be populated with something.
            if ($decode) {
				$this->checkJSON();
                $response = json_decode($this->response, TRUE);
            } else {
                $response = $this->response;
            }
            return $response;
        } else {
            return false;
        }
 
    }
	
	/**
     * simplePost
     * Used when the action is a very simple dump of the data provided by the endpoint (for POST endpoints)
     * @return array
     */
    public function simplePost($endpoint, $postargs, $decode = true, $sendJSON = false) {
 
        return $this->simpleOther('POST',$endpoint, $postargs, $decode);
 
    }
	
	
    /**
     * simpleGet
     * Used when the action is a very simple dump of the data provided by the endpoint (most GET requests)
     * @return array
     */
    public function simpleOther($method, $endpoint, $postargs = false, $decode = true) {
 
        //simply refresh the request and point it at the endpoint.
        $this->method = $method;
        $this->request = $postargs;
        $this->endpoint = $endpoint;
 
        if ($this->sendRequest($endpoint, $sendJSON)) {
            //if it's successful, the response will be populated with something.
            if ($decode) {
				$this->checkJSON();
                $response = json_decode($this->response, TRUE);
            } else {
                $response = $this->response;
            }
            return $response;
        } else {
            return false;
        }
 
    }
	
	
    /**
     * request
     * Generic function to send whatever request has been prepared, and save the response.
     * @return bool true for success or false for fail
     */
    private function sendRequest($endpoint, $sendJSON = false) {
 
        $fullURL = $this->toggl_base_url . $endpoint;
 
        //init the curl request
        $ch = curl_init();
		curl_setopt($ch, CURLOPT_USERPWD, $this->userSecret.":api_token");
		
		if ($sendJSON) {
			$qry_str = json_encode($this->request);
			//echo $qry_str;
		} else {
        	$qry_str = http_build_query($this->request);
		}
 
        if ($this->method == "POST") {
            curl_setopt($ch, CURLOPT_POST, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $qry_str);
			
			if ($sendJSON) {
				curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json')); 
			}
 
        } elseif ($this->method == "GET") {
            $fullURL .= '?'.$qry_str;
 
        } elseif ($this->method == "PUT") {
            curl_setopt($ch, CURLOPT_PUT, 1);
            //curl_setopt($ch, CURLOPT_POSTFIELDS, $qry_str);
			
			if ($sendJSON) {
				curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json')); 
			}
 
        }
 
 
        curl_setopt($ch, CURLOPT_URL, $fullURL);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_TIMEOUT, '30');
 
 
        //send it off & save the result
        $content = trim(curl_exec($ch));
        curl_close($ch);
 
        if ($content) {
            $this->response = $content;
            return true;
        } else {
            return false;
        }
 
 
    }
	
}

z_example.php

<?php
require "toggl_v8_sdk.php";
define('TOGGL_API', 'YOUR API KEY GOES HERE');
$toggl = new Toggl(TOGGL_API);

print_r($toggl->me()); //show the person logged in

//now let's save a time session.
$data = array("duration"=>(60*10), //10mins
  				"billable"=>false,
					"start"=>date("c",strtotime("-10 minutes")), //10mins ago
					"pid"=>'YOUR PROJECT ID GOES HERE',
					"description"=>"Time spent playing WoW",
					"duronly"=>true, //only show the duration, not start & stops.
					"tags"=>array('games', 'warcraft'),
				);
				
print_r($toggl->timeEntrySave($data));