diff --git a/README.md b/README.md
index 0a973df..7731627 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,16 @@
 bomber
 ======
 
-Mass sender of email samples
+Simple program to send huge amounts of predefined email samples to an SMTP server.
+Just an excuse to try out Go, really...
+
+```
+Usage of bomber:
+  -c="all": Category of messages to send
+  -l=false: Only list available categories.
+  -n=100: Number of message to be sent
+  -s="localhost": SMTP server to send the message to
+  -samples="./samples/": Directory containing email message samples in JSON
+  -throttle=0: Throttle the message flow (msg/second).
+  -v=false: Prints details of execution.
+```
diff --git a/bomber.go b/bomber.go
new file mode 100644
index 0000000..df04472
--- /dev/null
+++ b/bomber.go
@@ -0,0 +1,184 @@
+package main
+
+import (
+	"github.com/fmgoncalves/bomber/encoding/mail/sample"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/smtp"
+	"flag"
+	"time"
+	"math/rand"
+	"strings"
+	"runtime"
+	"os"
+)
+
+const (
+	default_host = "localhost"
+	default_dir = "samples"
+	default_port = 25
+)
+
+func die(err error) {
+	if err != nil {
+		panic(fmt.Sprintf("%v", err))
+	}
+	return
+}
+
+func send_default_header(key string, value string, sample_keys map[string] struct{}, wc io.WriteCloser){
+	if _, contains := sample_keys[strings.ToLower(key)] ; !contains {
+		wc.Write([]byte(key + ":" + value + "\r\n"))
+	}
+}
+
+func hasCategory(s sample.MailSample, category string) bool {
+	c := strings.ToLower(category)
+	for _, s_category := range s.Type {
+		if c == strings.ToLower(s_category) {
+			return true
+		}
+	}
+	return false
+}
+
+func send_sample(host string, s sample.MailSample) error {
+	var err error
+	// Connect to the remote SMTP server.
+	var port int
+	if s.Port > 0 {
+		port = s.Port
+	} else {
+		port = default_port
+	}
+	c, err := smtp.Dial(fmt.Sprintf("%s:%d",host, port))
+	if err != nil { return err }
+	//die(err)
+	defer c.Quit()
+	// MAIL_FROM, TO
+	c.Mail(s.From)
+	c.Rcpt(s.To)
+	// DATA
+	wc, err := c.Data()
+	if err != nil { return err }
+	//die(err)
+	defer wc.Close()
+	// Default headers
+	keyz := s.DefinedHeaders()
+	send_default_header("From", s.From, keyz, wc)
+	send_default_header("To", s.To, keyz, wc)
+	send_default_header("Date", time.Now().UTC().Format(time.RFC822), keyz, wc)
+	send_default_header("Message-Id", fmt.Sprintf("<%v@crap>",rand.Int()), keyz, wc)
+
+	for _, h := range s.Headers {
+		wc.Write([]byte(h + "\r\n"))
+	}
+	wc.Write([]byte("\r\n"))
+	wc.Write([]byte(s.Body))
+	return err
+}
+
+func main() {
+	var (
+		SAMPLES_DIRECTORY string
+		HOST string
+		CATEGORY string
+		N_MESSAGES int
+		THROTTLING float64
+		LIST_ONLY bool
+		VERBOSE bool
+	)
+
+	flag.StringVar(&HOST, "s", default_host, "SMTP server to send the message to")
+	//flag.StringVar(&SAMPLES_DIRECTORY, "samples", default_dir, "Directory containing email message samples in JSON")
+	samples_dir := os.Getenv("BOMBER_SAMPLES")
+	if len(samples_dir) == 0 {
+		samples_dir = "samples"
+	}
+	flag.StringVar(&SAMPLES_DIRECTORY, "samples", samples_dir, "Directory containing email message samples in JSON")
+	flag.StringVar(&CATEGORY, "c", "all", "Category of messages to send")
+	flag.IntVar(&N_MESSAGES, "n", 100, "Number of message to be sent")
+	flag.Float64Var(&THROTTLING, "throttle", 0, "Throttle the message flow (msg/second).")
+	flag.BoolVar(&LIST_ONLY, "l", false, "Only list available categories.")
+	flag.BoolVar(&VERBOSE, "v", false, "Prints details of execution.")
+	flag.Parse()
+
+	l, err := ioutil.ReadDir(SAMPLES_DIRECTORY)
+	die(err)
+	sample_list := make([]sample.MailSample,len(l))
+	categories := make(map[string]bool)
+	idx := 0
+	for _, val := range l {
+		if ! val.IsDir() && strings.HasSuffix(val.Name(),".json") {
+			s, err := sample.Unmarshal(SAMPLES_DIRECTORY+"/"+val.Name())
+			if err != nil {
+				if VERBOSE {
+					fmt.Printf("Failed to load %s sample\n",val.Name())
+				}
+			}
+			if VERBOSE {
+				fmt.Printf("Loaded %s sample\n",val.Name())
+			}
+			if LIST_ONLY {
+				for _, s_category := range s.Type {
+					asdfg := strings.ToLower(s_category)
+					categories[asdfg] = true
+				}
+			}
+			if CATEGORY == "all" || hasCategory(s,CATEGORY) {
+				sample_list[idx] = s
+				idx++
+			}
+		}
+	}
+	if LIST_ONLY {
+		fmt.Printf("Categories found in samples:\n")
+		for cat, _ := range categories {
+			fmt.Printf("\t%v\n",cat)
+		}
+		return
+	}
+
+	if ( idx > 0 ){
+		sample_list = sample_list[0:idx]
+	} else {
+		panic("No samples to use.")
+	}
+
+	pn := runtime.NumCPU()
+	//runtime.GOMAXPROCS(pn)
+	if THROTTLING > 0 {
+		pn = int(THROTTLING)
+	}
+	if VERBOSE {
+		fmt.Printf("Sending %v messages in batches of %v\n", N_MESSAGES, pn);
+	}
+
+	c := make(chan int, pn)
+	for i:= 0; i < pn; i++ {
+		c <- 1
+	}
+	for i:= 0; i < N_MESSAGES; i++ {
+		<-c
+		go func (j int) {
+			if VERBOSE {
+				fmt.Printf("Sending message #%v\n",j+1)
+			}
+			err := send_sample(HOST, sample_list[rand.Int() % len(sample_list)])
+			if err != nil {
+					fmt.Printf("Failed to send message #%v: %v\n", j+1, err)
+			}
+			if THROTTLING > 0 {
+				// TODO throttling should consider the running time of send_sample
+				time.Sleep(time.Duration( (float64(pn) /THROTTLING) * 1000.0 * float64(time.Millisecond)))
+			}
+			c <- 1
+		}(i)
+	}
+	for i:= 0; i < pn; i++ {
+		<- c
+	}
+
+	return
+}
diff --git a/encoding/mail/sample/sample.go b/encoding/mail/sample/sample.go
new file mode 100644
index 0000000..13c8e3c
--- /dev/null
+++ b/encoding/mail/sample/sample.go
@@ -0,0 +1,85 @@
+package sample
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"path"
+	"strings"
+)
+
+type MailSample struct {
+	Type    		[]string
+	Port			int
+	To      		string
+	From    		string
+	Headers 		[]string
+	HeadersFile		string
+	Body    		string
+	BodyFile    	string
+}
+
+func (s MailSample) DefinedHeaders() map[string]struct{} {
+	keys_map := make(map[string] struct{})
+	for _, val := range s.Headers {
+		key := strings.SplitN(val,":",2)[0]
+		keys_map[strings.ToLower(key)] = struct{}{};
+	}
+	return keys_map;
+}
+
+
+
+func (s *MailSample) buildHeaders(file_path string) error {
+	var err error
+	if len(s.Headers) == 0 && len(s.HeadersFile) != 0 {
+		f, err := ioutil.ReadFile(path.Dir(file_path)+"/"+s.HeadersFile)
+		if err != nil {
+			return err
+		}
+		headers_aux := strings.Split(string(f), "\n")
+		headers := make([]string, len(headers_aux))
+		idx := -1
+		for _, val := range headers_aux {
+			if ! strings.HasPrefix(val," ") && ! strings.HasPrefix(val,"\t") {
+				idx++
+			} else {
+				headers[idx] += "\r\n"
+			}
+			headers[idx] += strings.TrimRight(val,"\r")
+		}
+		headers = headers[0:idx+1]
+		s.Headers = headers
+	}
+	return err
+}
+
+func (s *MailSample) buildBody(file_path string) error {
+	var err error
+	if len(s.Body) == 0 && len(s.BodyFile) != 0 {
+		f, err := ioutil.ReadFile(path.Dir(file_path)+"/"+s.BodyFile)
+		if err != nil {
+			return err
+		}
+		s.Body = string(f)
+	}
+	return err
+}
+
+func Unmarshal(file_path string) (MailSample, error){
+	var s MailSample
+	f, err := ioutil.ReadFile(file_path)
+	if err != nil {
+		return s, err
+	}
+	err = json.Unmarshal(f, &s)
+	if err != nil {
+		return s, err
+	}
+	if err := s.buildHeaders(file_path); err != nil {
+		return s, err
+	}
+	if err := s.buildBody(file_path) ; err != nil {
+		return s, err
+	}
+	return s, nil
+}
diff --git a/example_samples/eicar.body b/example_samples/eicar.body
new file mode 100644
index 0000000..77c9198
--- /dev/null
+++ b/example_samples/eicar.body
@@ -0,0 +1 @@
+X5O!P%@AP[4\\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
diff --git a/example_samples/eicar.json b/example_samples/eicar.json
new file mode 100644
index 0000000..3656c7f
--- /dev/null
+++ b/example_samples/eicar.json
@@ -0,0 +1,7 @@
+{
+	"From":"virus.sender@fakedomain.tld",
+	"To":"eicar@fakedomain.tld",
+	"Type": ["virus"],
+	"Headers": ["Subject: Eicar virus message"],
+	"BodyFile":"eicar.body"
+}
diff --git a/example_samples/gtube.json b/example_samples/gtube.json
new file mode 100644
index 0000000..7a4876c
--- /dev/null
+++ b/example_samples/gtube.json
@@ -0,0 +1,7 @@
+{
+	"From":"gtube.spamassassin@fakedomain.tld",
+	"To":"gTuBe@fakedomain.tld",
+	"Type": ["spam","gtube"],
+	"Headers": ["Subject: Generic Test for Unsolicited Bulk Email"],
+	"Body":"XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X"
+}