diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..338962b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,29 @@
+# Binaries
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary
+*.test
+
+# Output of the go coverage tool
+*.out
+
+# Dependency directories
+vendor/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Debug
+debug
+*.log
diff --git a/README.md b/README.md
index 3e44a4f..7c1b32d 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,308 @@
-# irontelemetry-go
-IronTelemetry SDK for Go - Error monitoring and crash reporting
+# IronTelemetry SDK for Go
+
+Error monitoring and crash reporting SDK for Go applications. Capture exceptions, track user journeys, and get insights to fix issues faster.
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/IronServices/irontelemetry-go.svg)](https://pkg.go.dev/github.com/IronServices/irontelemetry-go)
+[![Go Report Card](https://goreportcard.com/badge/github.com/IronServices/irontelemetry-go)](https://goreportcard.com/report/github.com/IronServices/irontelemetry-go)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
+
+## Installation
+
+```bash
+go get github.com/IronServices/irontelemetry-go
+```
+
+## Quick Start
+
+### Basic Exception Capture
+
+```go
+package main
+
+import (
+    "errors"
+    "log"
+
+    irontelemetry "github.com/IronServices/irontelemetry-go"
+)
+
+func main() {
+    // Initialize with your DSN
+    client, err := irontelemetry.New(irontelemetry.Options{
+        DSN: "https://pk_live_xxx@irontelemetry.com",
+    })
+    if err != nil {
+        log.Fatal(err)
+    }
+    defer client.Close()
+
+    // Capture exceptions
+    if err := doSomething(); err != nil {
+        client.CaptureException(err)
+    }
+}
+
+func doSomething() error {
+    return errors.New("something went wrong")
+}
+```
+
+### Journey Tracking
+
+Track user journeys to understand the context of errors:
+
+```go
+package main
+
+import (
+    irontelemetry "github.com/IronServices/irontelemetry-go"
+)
+
+func main() {
+    client, _ := irontelemetry.New(irontelemetry.Options{
+        DSN: "https://pk_live_xxx@irontelemetry.com",
+    })
+    defer client.Close()
+
+    // Start a journey
+    journey := client.StartJourney("Checkout Flow")
+    journey.SetUser("user-123", "user@example.com", "John Doe")
+
+    // Track steps
+    step := journey.StartStep("Validate Cart", irontelemetry.CategoryBusiness)
+    if err := validateCart(); err != nil {
+        step.Fail(err)
+        journey.Fail(err)
+        client.CaptureException(err)
+        return
+    }
+    step.Complete()
+
+    step = journey.StartStep("Process Payment", irontelemetry.CategoryBusiness)
+    if err := processPayment(); err != nil {
+        step.Fail(err)
+        journey.Fail(err)
+        client.CaptureException(err)
+        return
+    }
+    step.Complete()
+
+    journey.Complete()
+}
+```
+
+Or use the helper method:
+
+```go
+journey := client.StartJourney("Checkout Flow")
+
+err := journey.RunStep("Validate Cart", irontelemetry.CategoryBusiness, func() error {
+    return validateCart()
+})
+if err != nil {
+    journey.Fail(err)
+    client.CaptureException(err)
+    return
+}
+
+err = journey.RunStep("Process Payment", irontelemetry.CategoryBusiness, func() error {
+    return processPayment()
+})
+if err != nil {
+    journey.Fail(err)
+    client.CaptureException(err)
+    return
+}
+
+journey.Complete()
+```
+
+## Configuration
+
+```go
+client, err := irontelemetry.New(irontelemetry.Options{
+    DSN:         "https://pk_live_xxx@irontelemetry.com",
+    Environment: "production",
+    AppVersion:  "1.2.3",
+    SampleRate:  1.0, // 100% of events
+    Debug:       false,
+    BeforeSend: func(event *irontelemetry.TelemetryEvent) *irontelemetry.TelemetryEvent {
+        // Filter or modify events
+        if strings.Contains(event.Message, "expected") {
+            return nil // Drop the event
+        }
+        return event
+    },
+})
+```
+
+### Configuration Options
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `DSN` | string | required | Your Data Source Name |
+| `Environment` | string | "production" | Environment name |
+| `AppVersion` | string | "0.0.0" | Application version |
+| `SampleRate` | float64 | 1.0 | Sample rate (0.0 to 1.0) |
+| `MaxBreadcrumbs` | int | 100 | Max breadcrumbs to keep |
+| `Debug` | bool | false | Enable debug logging |
+| `BeforeSend` | func | nil | Hook to filter/modify events |
+| `EnableOfflineQueue` | bool | true | Enable offline queue |
+| `MaxOfflineQueueSize` | int | 500 | Max offline queue size |
+
+## Features
+
+- **Automatic Stack Traces**: Full stack traces captured with every exception
+- **Journey Tracking**: Track user flows and correlate errors with context
+- **Breadcrumbs**: Leave a trail of events leading up to an error
+- **User Context**: Associate errors with specific users
+- **Tags & Extras**: Add custom metadata to your events
+- **Context Support**: Full context.Context support for cancellation
+- **Thread-Safe**: All operations are safe for concurrent use
+
+## Breadcrumbs
+
+```go
+// Add simple breadcrumbs
+client.AddBreadcrumb("User clicked checkout button", irontelemetry.CategoryUI)
+client.AddBreadcrumb("Payment API called", irontelemetry.CategoryHTTP)
+
+// With level
+client.AddBreadcrumbWithLevel(
+    "User logged in",
+    irontelemetry.CategoryAuth,
+    irontelemetry.SeverityInfo,
+)
+
+// With data
+client.AddBreadcrumbWithData(
+    "API request completed",
+    irontelemetry.CategoryHTTP,
+    irontelemetry.SeverityInfo,
+    map[string]any{
+        "url":        "/api/checkout",
+        "statusCode": 200,
+        "duration":   150,
+    },
+)
+```
+
+### Breadcrumb Categories
+
+```go
+irontelemetry.CategoryUI           // User interface interactions
+irontelemetry.CategoryHTTP         // HTTP requests
+irontelemetry.CategoryNavigation   // Page/route navigation
+irontelemetry.CategoryConsole      // Console output
+irontelemetry.CategoryAuth         // Authentication events
+irontelemetry.CategoryBusiness     // Business logic events
+irontelemetry.CategoryNotification // Notification events
+irontelemetry.CategoryCustom       // Custom events
+```
+
+## Severity Levels
+
+```go
+irontelemetry.SeverityDebug
+irontelemetry.SeverityInfo
+irontelemetry.SeverityWarning
+irontelemetry.SeverityError
+irontelemetry.SeverityFatal
+```
+
+## User Context
+
+```go
+// Simple user ID
+client.SetUserByID("user-123")
+
+// With email
+client.SetUserWithEmail("user-123", "user@example.com")
+
+// Full user object
+client.SetUser(&irontelemetry.User{
+    ID:    "user-123",
+    Email: "user@example.com",
+    Name:  "John Doe",
+    Data: map[string]any{
+        "plan": "premium",
+    },
+})
+```
+
+## Tags and Extra Data
+
+```go
+// Set individual tags
+client.SetTag("release", "v1.2.3")
+client.SetTag("server", "prod-1")
+
+// Set multiple tags
+client.SetTags(map[string]string{
+    "release": "v1.2.3",
+    "server":  "prod-1",
+})
+
+// Set extra data
+client.SetExtra("request_id", "abc-123")
+client.SetExtras(map[string]any{
+    "request_id": "abc-123",
+    "user_agent": "Mozilla/5.0...",
+})
+```
+
+## Context Support
+
+All capture methods support context for cancellation:
+
+```go
+ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+defer cancel()
+
+result := client.CaptureExceptionWithContext(ctx, err)
+if !result.Success {
+    log.Printf("Failed to send event: %s", result.Error)
+}
+```
+
+## HTTP Middleware Example
+
+```go
+func TelemetryMiddleware(client *irontelemetry.Client) func(http.Handler) http.Handler {
+    return func(next http.Handler) http.Handler {
+        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+            client.AddBreadcrumbWithData(
+                "HTTP Request",
+                irontelemetry.CategoryHTTP,
+                irontelemetry.SeverityInfo,
+                map[string]any{
+                    "method": r.Method,
+                    "url":    r.URL.String(),
+                },
+            )
+
+            defer func() {
+                if err := recover(); err != nil {
+                    client.CaptureException(fmt.Errorf("panic: %v", err))
+                    panic(err) // Re-panic
+                }
+            }()
+
+            next.ServeHTTP(w, r)
+        })
+    }
+}
+```
+
+## Requirements
+
+- Go 1.21+
+
+## Links
+
+- [Documentation](https://www.irontelemetry.com/docs)
+- [Dashboard](https://www.irontelemetry.com)
+
+## License
+
+MIT License - see [LICENSE](LICENSE) for details.
diff --git a/breadcrumbs.go b/breadcrumbs.go
new file mode 100644
index 0000000..c954b49
--- /dev/null
+++ b/breadcrumbs.go
@@ -0,0 +1,96 @@
+package irontelemetry
+
+import (
+	"sync"
+	"time"
+)
+
+// BreadcrumbManager manages a ring buffer of breadcrumbs
+type BreadcrumbManager struct {
+	mu             sync.RWMutex
+	breadcrumbs    []Breadcrumb
+	maxBreadcrumbs int
+}
+
+// NewBreadcrumbManager creates a new BreadcrumbManager
+func NewBreadcrumbManager(maxBreadcrumbs int) *BreadcrumbManager {
+	return &BreadcrumbManager{
+		breadcrumbs:    make([]Breadcrumb, 0, maxBreadcrumbs),
+		maxBreadcrumbs: maxBreadcrumbs,
+	}
+}
+
+// Add adds a breadcrumb to the ring buffer
+func (bm *BreadcrumbManager) Add(breadcrumb Breadcrumb) {
+	bm.mu.Lock()
+	defer bm.mu.Unlock()
+
+	if breadcrumb.Timestamp.IsZero() {
+		breadcrumb.Timestamp = time.Now()
+	}
+
+	if len(bm.breadcrumbs) >= bm.maxBreadcrumbs {
+		// Shift elements to make room (ring buffer behavior)
+		copy(bm.breadcrumbs, bm.breadcrumbs[1:])
+		bm.breadcrumbs = bm.breadcrumbs[:len(bm.breadcrumbs)-1]
+	}
+
+	bm.breadcrumbs = append(bm.breadcrumbs, breadcrumb)
+}
+
+// AddSimple adds a simple breadcrumb with just a message and category
+func (bm *BreadcrumbManager) AddSimple(message string, category BreadcrumbCategory) {
+	bm.Add(Breadcrumb{
+		Timestamp: time.Now(),
+		Category:  category,
+		Message:   message,
+		Level:     SeverityInfo,
+	})
+}
+
+// AddWithLevel adds a breadcrumb with a specific level
+func (bm *BreadcrumbManager) AddWithLevel(message string, category BreadcrumbCategory, level SeverityLevel) {
+	bm.Add(Breadcrumb{
+		Timestamp: time.Now(),
+		Category:  category,
+		Message:   message,
+		Level:     level,
+	})
+}
+
+// AddWithData adds a breadcrumb with additional data
+func (bm *BreadcrumbManager) AddWithData(message string, category BreadcrumbCategory, level SeverityLevel, data map[string]any) {
+	bm.Add(Breadcrumb{
+		Timestamp: time.Now(),
+		Category:  category,
+		Message:   message,
+		Level:     level,
+		Data:      data,
+	})
+}
+
+// GetAll returns a copy of all breadcrumbs
+func (bm *BreadcrumbManager) GetAll() []Breadcrumb {
+	bm.mu.RLock()
+	defer bm.mu.RUnlock()
+
+	result := make([]Breadcrumb, len(bm.breadcrumbs))
+	copy(result, bm.breadcrumbs)
+	return result
+}
+
+// Clear removes all breadcrumbs
+func (bm *BreadcrumbManager) Clear() {
+	bm.mu.Lock()
+	defer bm.mu.Unlock()
+
+	bm.breadcrumbs = make([]Breadcrumb, 0, bm.maxBreadcrumbs)
+}
+
+// Count returns the number of breadcrumbs
+func (bm *BreadcrumbManager) Count() int {
+	bm.mu.RLock()
+	defer bm.mu.RUnlock()
+
+	return len(bm.breadcrumbs)
+}
diff --git a/client.go b/client.go
new file mode 100644
index 0000000..3c57fbd
--- /dev/null
+++ b/client.go
@@ -0,0 +1,284 @@
+package irontelemetry
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"runtime"
+	"sync"
+	"time"
+)
+
+// Client is the main IronTelemetry client
+type Client struct {
+	mu          sync.RWMutex
+	opts        Options
+	parsedDSN   *ParsedDSN
+	transport   *Transport
+	breadcrumbs *BreadcrumbManager
+	journeys    *JourneyManager
+	user        *User
+	tags        map[string]string
+	extra       map[string]any
+	initialized bool
+}
+
+// New creates a new IronTelemetry client
+func New(opts Options) (*Client, error) {
+	resolvedOpts, parsedDSN, err := ResolveOptions(opts)
+	if err != nil {
+		return nil, err
+	}
+
+	client := &Client{
+		opts:        resolvedOpts,
+		parsedDSN:   parsedDSN,
+		transport:   NewTransport(parsedDSN, resolvedOpts.APIBaseURL, resolvedOpts.Debug),
+		breadcrumbs: NewBreadcrumbManager(resolvedOpts.MaxBreadcrumbs),
+		tags:        make(map[string]string),
+		extra:       make(map[string]any),
+		initialized: true,
+	}
+	client.journeys = NewJourneyManager(client)
+
+	if opts.Debug {
+		fmt.Printf("[IronTelemetry] Initialized with DSN: %s\n", parsedDSN.APIBaseURL)
+	}
+
+	return client, nil
+}
+
+// CaptureException captures an error and sends it to the server
+func (c *Client) CaptureException(err error) SendResult {
+	return c.CaptureExceptionWithContext(context.Background(), err)
+}
+
+// CaptureExceptionWithContext captures an error with context
+func (c *Client) CaptureExceptionWithContext(ctx context.Context, err error) SendResult {
+	if err == nil {
+		return SendResult{Success: false, Error: "nil error"}
+	}
+
+	event := c.createEvent(SeverityError, err.Error())
+	event.Exception = &ExceptionInfo{
+		Type:       fmt.Sprintf("%T", err),
+		Message:    err.Error(),
+		Stacktrace: captureStacktrace(3),
+	}
+
+	return c.sendEvent(ctx, event)
+}
+
+// CaptureMessage captures a message and sends it to the server
+func (c *Client) CaptureMessage(message string, level SeverityLevel) SendResult {
+	return c.CaptureMessageWithContext(context.Background(), message, level)
+}
+
+// CaptureMessageWithContext captures a message with context
+func (c *Client) CaptureMessageWithContext(ctx context.Context, message string, level SeverityLevel) SendResult {
+	event := c.createEvent(level, message)
+	return c.sendEvent(ctx, event)
+}
+
+// AddBreadcrumb adds a breadcrumb
+func (c *Client) AddBreadcrumb(message string, category BreadcrumbCategory) {
+	c.breadcrumbs.AddSimple(message, category)
+}
+
+// AddBreadcrumbWithLevel adds a breadcrumb with a level
+func (c *Client) AddBreadcrumbWithLevel(message string, category BreadcrumbCategory, level SeverityLevel) {
+	c.breadcrumbs.AddWithLevel(message, category, level)
+}
+
+// AddBreadcrumbWithData adds a breadcrumb with data
+func (c *Client) AddBreadcrumbWithData(message string, category BreadcrumbCategory, level SeverityLevel, data map[string]any) {
+	c.breadcrumbs.AddWithData(message, category, level, data)
+}
+
+// SetUser sets the user context
+func (c *Client) SetUser(user *User) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.user = user
+}
+
+// SetUserByID sets the user context by ID
+func (c *Client) SetUserByID(id string) {
+	c.SetUser(&User{ID: id})
+}
+
+// SetUserWithEmail sets the user context with ID and email
+func (c *Client) SetUserWithEmail(id, email string) {
+	c.SetUser(&User{ID: id, Email: email})
+}
+
+// SetTag sets a tag
+func (c *Client) SetTag(key, value string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.tags[key] = value
+}
+
+// SetTags sets multiple tags
+func (c *Client) SetTags(tags map[string]string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for k, v := range tags {
+		c.tags[k] = v
+	}
+}
+
+// SetExtra sets extra data
+func (c *Client) SetExtra(key string, value any) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.extra[key] = value
+}
+
+// SetExtras sets multiple extra data values
+func (c *Client) SetExtras(extras map[string]any) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for k, v := range extras {
+		c.extra[k] = v
+	}
+}
+
+// StartJourney starts a new journey
+func (c *Client) StartJourney(name string) *Journey {
+	return c.journeys.StartJourney(name)
+}
+
+// GetCurrentJourney returns the current journey context
+func (c *Client) GetCurrentJourney() *JourneyContext {
+	return c.journeys.GetCurrent()
+}
+
+// ClearBreadcrumbs clears all breadcrumbs
+func (c *Client) ClearBreadcrumbs() {
+	c.breadcrumbs.Clear()
+}
+
+// Flush flushes any pending events (placeholder for offline queue)
+func (c *Client) Flush() {
+	// Future: Implement offline queue flushing
+}
+
+// Close closes the client and flushes pending events
+func (c *Client) Close() {
+	c.Flush()
+}
+
+func (c *Client) createEvent(level SeverityLevel, message string) *TelemetryEvent {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	// Copy tags
+	tags := make(map[string]string, len(c.tags))
+	for k, v := range c.tags {
+		tags[k] = v
+	}
+
+	// Copy extra
+	extra := make(map[string]any, len(c.extra))
+	for k, v := range c.extra {
+		extra[k] = v
+	}
+
+	event := &TelemetryEvent{
+		EventID:     GenerateEventID(),
+		Timestamp:   time.Now(),
+		Level:       level,
+		Message:     message,
+		Tags:        tags,
+		Extra:       extra,
+		Breadcrumbs: c.breadcrumbs.GetAll(),
+		Environment: c.opts.Environment,
+		AppVersion:  c.opts.AppVersion,
+		Platform: PlatformInfo{
+			Name:    "go",
+			Version: runtime.Version(),
+			OS:      runtime.GOOS + "/" + runtime.GOARCH,
+		},
+	}
+
+	// Copy user if set
+	if c.user != nil {
+		event.User = &User{
+			ID:    c.user.ID,
+			Email: c.user.Email,
+			Name:  c.user.Name,
+		}
+		if c.user.Data != nil {
+			event.User.Data = make(map[string]any, len(c.user.Data))
+			for k, v := range c.user.Data {
+				event.User.Data[k] = v
+			}
+		}
+	}
+
+	// Copy journey if active
+	if journey := c.journeys.GetCurrent(); journey != nil {
+		event.Journey = &JourneyContext{
+			JourneyID:   journey.JourneyID,
+			Name:        journey.Name,
+			CurrentStep: journey.CurrentStep,
+			StartedAt:   journey.StartedAt,
+			Metadata:    make(map[string]any, len(journey.Metadata)),
+		}
+		for k, v := range journey.Metadata {
+			event.Journey.Metadata[k] = v
+		}
+	}
+
+	return event
+}
+
+func (c *Client) sendEvent(ctx context.Context, event *TelemetryEvent) SendResult {
+	// Check sample rate
+	if c.opts.SampleRate < 1.0 && rand.Float64() > c.opts.SampleRate {
+		if c.opts.Debug {
+			fmt.Printf("[IronTelemetry] Event sampled out: %s\n", event.EventID)
+		}
+		return SendResult{Success: true, EventID: event.EventID}
+	}
+
+	// Apply beforeSend hook
+	if c.opts.BeforeSend != nil {
+		event = c.opts.BeforeSend(event)
+		if event == nil {
+			if c.opts.Debug {
+				fmt.Println("[IronTelemetry] Event dropped by beforeSend hook")
+			}
+			return SendResult{Success: true}
+		}
+	}
+
+	return c.transport.Send(ctx, event)
+}
+
+func captureStacktrace(skip int) []StackFrame {
+	var frames []StackFrame
+	pcs := make([]uintptr, 32)
+	n := runtime.Callers(skip, pcs)
+	if n == 0 {
+		return frames
+	}
+
+	pcs = pcs[:n]
+	runtimeFrames := runtime.CallersFrames(pcs)
+
+	for {
+		frame, more := runtimeFrames.Next()
+		frames = append(frames, StackFrame{
+			Function: frame.Function,
+			Filename: frame.File,
+			Lineno:   frame.Line,
+		})
+		if !more {
+			break
+		}
+	}
+
+	return frames
+}
diff --git a/config.go b/config.go
new file mode 100644
index 0000000..8ac5c9d
--- /dev/null
+++ b/config.go
@@ -0,0 +1,72 @@
+package irontelemetry
+
+import (
+	"errors"
+	"net/url"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+// ParseDSN parses a DSN string into its components
+// Format: https://pk_live_xxx@irontelemetry.com
+func ParseDSN(dsn string) (*ParsedDSN, error) {
+	parsed, err := url.Parse(dsn)
+	if err != nil {
+		return nil, errors.New("invalid DSN format: " + dsn)
+	}
+
+	publicKey := parsed.User.Username()
+	if publicKey == "" || !strings.HasPrefix(publicKey, "pk_") {
+		return nil, errors.New("DSN must contain a valid public key starting with pk_")
+	}
+
+	return &ParsedDSN{
+		PublicKey:  publicKey,
+		Host:       parsed.Host,
+		Protocol:   parsed.Scheme,
+		APIBaseURL: parsed.Scheme + "://" + parsed.Host,
+	}, nil
+}
+
+// GenerateEventID generates a unique event ID
+func GenerateEventID() string {
+	return uuid.New().String()
+}
+
+// ResolveOptions validates and fills in defaults for options
+func ResolveOptions(opts Options) (Options, *ParsedDSN, error) {
+	parsedDSN, err := ParseDSN(opts.DSN)
+	if err != nil {
+		return opts, nil, err
+	}
+
+	defaults := DefaultOptions()
+
+	if opts.Environment == "" {
+		opts.Environment = defaults.Environment
+	}
+	if opts.AppVersion == "" {
+		opts.AppVersion = defaults.AppVersion
+	}
+	if opts.SampleRate == 0 {
+		opts.SampleRate = defaults.SampleRate
+	}
+	if opts.SampleRate < 0 {
+		opts.SampleRate = 0
+	}
+	if opts.SampleRate > 1 {
+		opts.SampleRate = 1
+	}
+	if opts.MaxBreadcrumbs == 0 {
+		opts.MaxBreadcrumbs = defaults.MaxBreadcrumbs
+	}
+	if opts.MaxOfflineQueueSize == 0 {
+		opts.MaxOfflineQueueSize = defaults.MaxOfflineQueueSize
+	}
+	if opts.APIBaseURL == "" {
+		opts.APIBaseURL = parsedDSN.APIBaseURL
+	}
+
+	return opts, parsedDSN, nil
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..0100697
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,7 @@
+module github.com/IronServices/irontelemetry-go
+
+go 1.21
+
+require (
+	github.com/google/uuid v1.5.0
+)
diff --git a/journey.go b/journey.go
new file mode 100644
index 0000000..91f1bf7
--- /dev/null
+++ b/journey.go
@@ -0,0 +1,227 @@
+package irontelemetry
+
+import (
+	"sync"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// JourneyManager manages journey context
+type JourneyManager struct {
+	mu      sync.RWMutex
+	current *JourneyContext
+	client  *Client
+}
+
+// NewJourneyManager creates a new JourneyManager
+func NewJourneyManager(client *Client) *JourneyManager {
+	return &JourneyManager{
+		client: client,
+	}
+}
+
+// StartJourney starts a new journey
+func (jm *JourneyManager) StartJourney(name string) *Journey {
+	jm.mu.Lock()
+	defer jm.mu.Unlock()
+
+	ctx := &JourneyContext{
+		JourneyID:   uuid.New().String(),
+		Name:        name,
+		StartedAt:   time.Now(),
+		Metadata:    make(map[string]any),
+	}
+	jm.current = ctx
+
+	// Add breadcrumb for journey start
+	if jm.client != nil {
+		jm.client.AddBreadcrumb("Started journey: "+name, CategoryBusiness)
+	}
+
+	return &Journey{
+		manager: jm,
+		context: ctx,
+	}
+}
+
+// GetCurrent returns the current journey context
+func (jm *JourneyManager) GetCurrent() *JourneyContext {
+	jm.mu.RLock()
+	defer jm.mu.RUnlock()
+
+	return jm.current
+}
+
+// Clear clears the current journey
+func (jm *JourneyManager) Clear() {
+	jm.mu.Lock()
+	defer jm.mu.Unlock()
+
+	jm.current = nil
+}
+
+// Journey represents an active journey
+type Journey struct {
+	manager *JourneyManager
+	context *JourneyContext
+}
+
+// SetUser sets the user for the journey
+func (j *Journey) SetUser(id, email, name string) *Journey {
+	j.manager.mu.Lock()
+	defer j.manager.mu.Unlock()
+
+	j.context.Metadata["userId"] = id
+	if email != "" {
+		j.context.Metadata["userEmail"] = email
+	}
+	if name != "" {
+		j.context.Metadata["userName"] = name
+	}
+
+	return j
+}
+
+// SetMetadata sets metadata for the journey
+func (j *Journey) SetMetadata(key string, value any) *Journey {
+	j.manager.mu.Lock()
+	defer j.manager.mu.Unlock()
+
+	j.context.Metadata[key] = value
+	return j
+}
+
+// StartStep starts a new step in the journey
+func (j *Journey) StartStep(name string, category BreadcrumbCategory) *Step {
+	j.manager.mu.Lock()
+	j.context.CurrentStep = name
+	j.manager.mu.Unlock()
+
+	// Add breadcrumb for step start
+	if j.manager.client != nil {
+		j.manager.client.AddBreadcrumbWithData(
+			"Started step: "+name,
+			category,
+			SeverityInfo,
+			map[string]any{
+				"journeyId":   j.context.JourneyID,
+				"journeyName": j.context.Name,
+			},
+		)
+	}
+
+	return &Step{
+		journey:   j,
+		name:      name,
+		category:  category,
+		startedAt: time.Now(),
+		data:      make(map[string]any),
+	}
+}
+
+// Complete completes the journey successfully
+func (j *Journey) Complete() {
+	if j.manager.client != nil {
+		j.manager.client.AddBreadcrumbWithData(
+			"Completed journey: "+j.context.Name,
+			CategoryBusiness,
+			SeverityInfo,
+			map[string]any{
+				"journeyId": j.context.JourneyID,
+				"duration":  time.Since(j.context.StartedAt).Milliseconds(),
+			},
+		)
+	}
+	j.manager.Clear()
+}
+
+// Fail marks the journey as failed
+func (j *Journey) Fail(err error) {
+	if j.manager.client != nil {
+		data := map[string]any{
+			"journeyId": j.context.JourneyID,
+			"duration":  time.Since(j.context.StartedAt).Milliseconds(),
+		}
+		if err != nil {
+			data["error"] = err.Error()
+		}
+		j.manager.client.AddBreadcrumbWithData(
+			"Failed journey: "+j.context.Name,
+			CategoryBusiness,
+			SeverityError,
+			data,
+		)
+	}
+	j.manager.Clear()
+}
+
+// Step represents a step within a journey
+type Step struct {
+	journey   *Journey
+	name      string
+	category  BreadcrumbCategory
+	startedAt time.Time
+	data      map[string]any
+}
+
+// SetData sets data for the step
+func (s *Step) SetData(key string, value any) *Step {
+	s.data[key] = value
+	return s
+}
+
+// Complete completes the step successfully
+func (s *Step) Complete() {
+	if s.journey.manager.client != nil {
+		data := map[string]any{
+			"journeyId":   s.journey.context.JourneyID,
+			"journeyName": s.journey.context.Name,
+			"duration":    time.Since(s.startedAt).Milliseconds(),
+		}
+		for k, v := range s.data {
+			data[k] = v
+		}
+		s.journey.manager.client.AddBreadcrumbWithData(
+			"Completed step: "+s.name,
+			s.category,
+			SeverityInfo,
+			data,
+		)
+	}
+}
+
+// Fail marks the step as failed
+func (s *Step) Fail(err error) {
+	if s.journey.manager.client != nil {
+		data := map[string]any{
+			"journeyId":   s.journey.context.JourneyID,
+			"journeyName": s.journey.context.Name,
+			"duration":    time.Since(s.startedAt).Milliseconds(),
+		}
+		for k, v := range s.data {
+			data[k] = v
+		}
+		if err != nil {
+			data["error"] = err.Error()
+		}
+		s.journey.manager.client.AddBreadcrumbWithData(
+			"Failed step: "+s.name,
+			s.category,
+			SeverityError,
+			data,
+		)
+	}
+}
+
+// RunStep is a helper that runs a function as a step
+func (j *Journey) RunStep(name string, category BreadcrumbCategory, fn func() error) error {
+	step := j.StartStep(name, category)
+	err := fn()
+	if err != nil {
+		step.Fail(err)
+		return err
+	}
+	step.Complete()
+	return nil
+}
diff --git a/transport.go b/transport.go
new file mode 100644
index 0000000..50b4858
--- /dev/null
+++ b/transport.go
@@ -0,0 +1,171 @@
+package irontelemetry
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+// Transport handles HTTP communication with the server
+type Transport struct {
+	apiBaseURL string
+	publicKey  string
+	debug      bool
+	client     *http.Client
+}
+
+// NewTransport creates a new Transport
+func NewTransport(parsedDSN *ParsedDSN, apiBaseURL string, debug bool) *Transport {
+	return &Transport{
+		apiBaseURL: apiBaseURL,
+		publicKey:  parsedDSN.PublicKey,
+		debug:      debug,
+		client: &http.Client{
+			Timeout: 30 * time.Second,
+		},
+	}
+}
+
+// Send sends an event to the server
+func (t *Transport) Send(ctx context.Context, event *TelemetryEvent) SendResult {
+	url := t.apiBaseURL + "/api/v1/events"
+
+	body, err := json.Marshal(t.serializeEvent(event))
+	if err != nil {
+		return SendResult{Success: false, Error: err.Error()}
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(body))
+	if err != nil {
+		return SendResult{Success: false, Error: err.Error()}
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-Public-Key", t.publicKey)
+
+	resp, err := t.client.Do(req)
+	if err != nil {
+		if t.debug {
+			fmt.Printf("[IronTelemetry] Failed to send event: %v\n", err)
+		}
+		return SendResult{Success: false, Error: err.Error()}
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		bodyBytes, _ := io.ReadAll(resp.Body)
+		errMsg := fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(bodyBytes))
+		if t.debug {
+			fmt.Printf("[IronTelemetry] Failed to send event: %s\n", errMsg)
+		}
+		return SendResult{Success: false, Error: errMsg}
+	}
+
+	var result struct {
+		EventID string `json:"eventId"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		// Even if we can't decode, the request succeeded
+		result.EventID = event.EventID
+	}
+
+	if t.debug {
+		fmt.Printf("[IronTelemetry] Event sent successfully: %s\n", event.EventID)
+	}
+
+	return SendResult{
+		Success: true,
+		EventID: result.EventID,
+	}
+}
+
+// IsOnline checks if the server is reachable
+func (t *Transport) IsOnline(ctx context.Context) bool {
+	url := t.apiBaseURL + "/api/v1/health"
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return false
+	}
+
+	req.Header.Set("X-Public-Key", t.publicKey)
+
+	resp, err := t.client.Do(req)
+	if err != nil {
+		return false
+	}
+	defer resp.Body.Close()
+
+	return resp.StatusCode == 200
+}
+
+func (t *Transport) serializeEvent(event *TelemetryEvent) map[string]any {
+	breadcrumbs := make([]map[string]any, len(event.Breadcrumbs))
+	for i, b := range event.Breadcrumbs {
+		breadcrumbs[i] = map[string]any{
+			"timestamp": b.Timestamp.Format(time.RFC3339),
+			"category":  b.Category,
+			"message":   b.Message,
+			"level":     b.Level,
+			"data":      b.Data,
+		}
+	}
+
+	result := map[string]any{
+		"eventId":     event.EventID,
+		"timestamp":   event.Timestamp.Format(time.RFC3339),
+		"level":       event.Level,
+		"message":     event.Message,
+		"tags":        event.Tags,
+		"extra":       event.Extra,
+		"breadcrumbs": breadcrumbs,
+		"environment": event.Environment,
+		"appVersion":  event.AppVersion,
+		"platform": map[string]any{
+			"name":    event.Platform.Name,
+			"version": event.Platform.Version,
+			"os":      event.Platform.OS,
+		},
+	}
+
+	if event.Exception != nil {
+		stacktrace := make([]map[string]any, len(event.Exception.Stacktrace))
+		for i, f := range event.Exception.Stacktrace {
+			stacktrace[i] = map[string]any{
+				"function": f.Function,
+				"filename": f.Filename,
+				"lineno":   f.Lineno,
+			}
+		}
+		result["exception"] = map[string]any{
+			"type":       event.Exception.Type,
+			"message":    event.Exception.Message,
+			"stacktrace": stacktrace,
+		}
+	}
+
+	if event.User != nil {
+		result["user"] = map[string]any{
+			"id":    event.User.ID,
+			"email": event.User.Email,
+			"name":  event.User.Name,
+			"data":  event.User.Data,
+		}
+	}
+
+	if event.Journey != nil {
+		result["journey"] = map[string]any{
+			"journeyId":   event.Journey.JourneyID,
+			"name":        event.Journey.Name,
+			"currentStep": event.Journey.CurrentStep,
+			"startedAt":   event.Journey.StartedAt.Format(time.RFC3339),
+			"metadata":    event.Journey.Metadata,
+		}
+	}
+
+	return result
+}
diff --git a/types.go b/types.go
new file mode 100644
index 0000000..a193ea6
--- /dev/null
+++ b/types.go
@@ -0,0 +1,158 @@
+package irontelemetry
+
+import "time"
+
+// SeverityLevel represents the severity of an event
+type SeverityLevel string
+
+const (
+	SeverityDebug   SeverityLevel = "debug"
+	SeverityInfo    SeverityLevel = "info"
+	SeverityWarning SeverityLevel = "warning"
+	SeverityError   SeverityLevel = "error"
+	SeverityFatal   SeverityLevel = "fatal"
+)
+
+// BreadcrumbCategory represents the category of a breadcrumb
+type BreadcrumbCategory string
+
+const (
+	CategoryUI           BreadcrumbCategory = "ui"
+	CategoryHTTP         BreadcrumbCategory = "http"
+	CategoryNavigation   BreadcrumbCategory = "navigation"
+	CategoryConsole      BreadcrumbCategory = "console"
+	CategoryAuth         BreadcrumbCategory = "auth"
+	CategoryBusiness     BreadcrumbCategory = "business"
+	CategoryNotification BreadcrumbCategory = "notification"
+	CategoryCustom       BreadcrumbCategory = "custom"
+)
+
+// Breadcrumb represents an event leading up to an error
+type Breadcrumb struct {
+	Timestamp time.Time            `json:"timestamp"`
+	Category  BreadcrumbCategory   `json:"category"`
+	Message   string               `json:"message"`
+	Level     SeverityLevel        `json:"level,omitempty"`
+	Data      map[string]any       `json:"data,omitempty"`
+}
+
+// User represents user information for context
+type User struct {
+	ID    string         `json:"id"`
+	Email string         `json:"email,omitempty"`
+	Name  string         `json:"name,omitempty"`
+	Data  map[string]any `json:"data,omitempty"`
+}
+
+// StackFrame represents a single frame in a stack trace
+type StackFrame struct {
+	Function string   `json:"function,omitempty"`
+	Filename string   `json:"filename,omitempty"`
+	Lineno   int      `json:"lineno,omitempty"`
+	Colno    int      `json:"colno,omitempty"`
+	Context  []string `json:"context,omitempty"`
+}
+
+// ExceptionInfo represents exception/error information
+type ExceptionInfo struct {
+	Type       string       `json:"type"`
+	Message    string       `json:"message"`
+	Stacktrace []StackFrame `json:"stacktrace,omitempty"`
+}
+
+// PlatformInfo represents platform/runtime information
+type PlatformInfo struct {
+	Name    string `json:"name"`
+	Version string `json:"version,omitempty"`
+	OS      string `json:"os,omitempty"`
+}
+
+// JourneyContext represents journey context for tracking user flows
+type JourneyContext struct {
+	JourneyID   string         `json:"journeyId"`
+	Name        string         `json:"name"`
+	CurrentStep string         `json:"currentStep,omitempty"`
+	StartedAt   time.Time      `json:"startedAt"`
+	Metadata    map[string]any `json:"metadata"`
+}
+
+// TelemetryEvent represents an event payload sent to the server
+type TelemetryEvent struct {
+	EventID     string          `json:"eventId"`
+	Timestamp   time.Time       `json:"timestamp"`
+	Level       SeverityLevel   `json:"level"`
+	Message     string          `json:"message,omitempty"`
+	Exception   *ExceptionInfo  `json:"exception,omitempty"`
+	User        *User           `json:"user,omitempty"`
+	Tags        map[string]string `json:"tags"`
+	Extra       map[string]any  `json:"extra"`
+	Breadcrumbs []Breadcrumb    `json:"breadcrumbs"`
+	Journey     *JourneyContext `json:"journey,omitempty"`
+	Environment string          `json:"environment,omitempty"`
+	AppVersion  string          `json:"appVersion,omitempty"`
+	Platform    PlatformInfo    `json:"platform"`
+}
+
+// ParsedDSN represents parsed DSN components
+type ParsedDSN struct {
+	PublicKey  string
+	Host       string
+	Protocol   string
+	APIBaseURL string
+}
+
+// SendResult represents the result of sending an event
+type SendResult struct {
+	Success bool
+	EventID string
+	Error   string
+	Queued  bool
+}
+
+// Options represents options for initializing the SDK
+type Options struct {
+	// DSN containing the public key
+	// Format: https://pk_live_xxx@irontelemetry.com
+	DSN string
+
+	// Environment name (e.g., 'production', 'staging')
+	Environment string
+
+	// Application version
+	AppVersion string
+
+	// Sample rate for events (0.0 to 1.0)
+	SampleRate float64
+
+	// Maximum number of breadcrumbs to keep
+	MaxBreadcrumbs int
+
+	// Enable debug logging
+	Debug bool
+
+	// Hook called before sending an event
+	// Return nil to drop the event
+	BeforeSend func(*TelemetryEvent) *TelemetryEvent
+
+	// Enable offline queue for failed events
+	EnableOfflineQueue bool
+
+	// Maximum size of the offline queue
+	MaxOfflineQueueSize int
+
+	// API base URL (defaults to parsed from DSN)
+	APIBaseURL string
+}
+
+// DefaultOptions returns Options with default values
+func DefaultOptions() Options {
+	return Options{
+		Environment:         "production",
+		AppVersion:          "0.0.0",
+		SampleRate:          1.0,
+		MaxBreadcrumbs:      100,
+		Debug:               false,
+		EnableOfflineQueue:  true,
+		MaxOfflineQueueSize: 500,
+	}
+}