PHP_XLSXWriter

This library is designed to be lightweight, and have minimal memory usage.

It is designed to output an Excel compatible spreadsheet in (Office 2007+) xlsx format, with just basic features supported:

supports PHP 5.2.1+
takes UTF-8 encoded input
multiple worksheets
supports currency/date/numeric cell formatting, simple formulas
supports basic cell styling
supports writing huge 100K+ row spreadsheets

Never run out of memory with PHPExcel again.

Simple PHP CLI example:

$data = array(
    array('year','month','amount'),
    array('2003','1','220'),
    array('2003','2','153.5'),
);

$writer = new XLSXWriter();
$writer->writeSheet($data);
$writer->writeToFile('output.xlsx');

Simple/Advanced Cell Formats:

$header = array(
  'created'=>'date',
  'product_id'=>'integer',
  'quantity'=>'#,##0',
  'amount'=>'price',
  'description'=>'string',
  'tax'=>'[$$-1009]#,##0.00;[RED]-[$$-1009]#,##0.00',
);
$data = array(
    array('2015-01-01',873,1,'44.00','misc','=D2*0.05'),
    array('2015-01-12',324,2,'88.00','none','=D3*0.05'),
);

$writer = new XLSXWriter();
$writer->writeSheetHeader('Sheet1', $header );
foreach($data as $row)
	$writer->writeSheetRow('Sheet1', $row );
$writer->writeToFile('example.xlsx');

50000 rows: (1.4s, 0MB memory usage)

include_once("xlsxwriter.class.php");
$writer = new XLSXWriter();
$writer->writeSheetHeader('Sheet1', array('c1'=>'integer','c2'=>'integer','c3'=>'integer','c4'=>'integer') );
for($i=0; $i<50000; $i++)
{
    $writer->writeSheetRow('Sheet1', array($i, $i+1, $i+2, $i+3) );
}
$writer->writeToFile('huge.xlsx');
echo '#'.floor((memory_get_peak_usage())/1024/1024)."MB"."\n";

rows	time	memory
50000	1.4s	0MB
100000	2.7s	0MB
150000	4.1s	0MB
200000	5.7s	0MB
250000	7.0s	0MB

Simple cell formats map to more advanced cell formats

simple formats	format code
string	@
integer	0
date	YYYY-MM-DD
datetime	YYYY-MM-DD HH:MM:SS
time	HH:MM:SS
price	#,##0.00
dollar	[$$-1009]#,##0.00;[RED]-[$$-1009]#,##0.00
euro	#,##0.00 [$€-407];[RED]-#,##0.00 [$€-407]

Basic cell styles have been available since version 0.30

style	allowed values
font	Arial, Times New Roman, Courier New, Comic Sans MS
font-size	8,9,10,11,12 ...
font-style	bold, italic, underline, strikethrough or multiple ie: 'bold,italic'
border	left, right, top, bottom, or multiple ie: 'top,left'
border-style	thin, medium, thick, dashDot, dashDotDot, dashed, dotted, double, hair, mediumDashDot, mediumDashDotDot, mediumDashed, slantDashDot
border-color	#RRGGBB, ie: #ff99cc or #f9c
color	#RRGGBB, ie: #ff99cc or #f9c
fill	#RRGGBB, ie: #eeffee or #efe
halign	general, left, right, justify, center
valign	bottom, center, distributed