diff --git a/config.go b/config.go
index 2a31c86..057bead 100644
--- a/config.go
+++ b/config.go
@@ -16,6 +16,7 @@ type Config struct {
 	AlgoExtension   bool         `json:"algo-ext"`          // forward algo field in jobs
 	Workers         WorkersMode  `json:"workers"`           // "rig-id", "user", "password", "agent", "ip", "false"
 	AccessLogFile   string       `json:"access-log-file"`   // "" = disabled
+	ShareLogFile    string       `json:"share-log-file"`    // "" = disabled
 	ReuseTimeout    int          `json:"reuse-timeout"`     // seconds; simple mode upstream reuse
 	Retries         int          `json:"retries"`           // pool reconnect attempts
 	RetryPause      int          `json:"retry-pause"`       // seconds between retries
diff --git a/proxy.go b/proxy.go
index 813911d..f9ab0f1 100644
--- a/proxy.go
+++ b/proxy.go
@@ -40,6 +40,7 @@ type Proxy struct {
 	rateLimit         *RateLimiter
 	httpServer        *http.Server
 	accessLog         *accessLogSink
+	shareLog          *shareLogSink
 	submitCount       atomic.Int64
 }
 
diff --git a/sharelog_impl.go b/sharelog_impl.go
new file mode 100644
index 0000000..56760c6
--- /dev/null
+++ b/sharelog_impl.go
@@ -0,0 +1,95 @@
+package proxy
+
+import (
+	"os"
+	"strings"
+	"sync"
+	"time"
+)
+
+type shareLogSink struct {
+	path string
+	file *os.File
+	mu   sync.Mutex
+}
+
+func newShareLogSink(path string) *shareLogSink {
+	return &shareLogSink{path: path}
+}
+
+func (l *shareLogSink) SetPath(path string) {
+	if l == nil {
+		return
+	}
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.path == path {
+		return
+	}
+	l.path = path
+	if l.file != nil {
+		_ = l.file.Close()
+		l.file = nil
+	}
+}
+
+func (l *shareLogSink) Close() {
+	if l == nil {
+		return
+	}
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.file != nil {
+		_ = l.file.Close()
+		l.file = nil
+	}
+}
+
+func (l *shareLogSink) OnAccept(e Event) {
+	if l == nil || e.Miner == nil {
+		return
+	}
+	l.writeLine("ACCEPT", e.Miner.User(), e.Diff, e.Latency, "")
+}
+
+func (l *shareLogSink) OnReject(e Event) {
+	if l == nil || e.Miner == nil {
+		return
+	}
+	l.writeLine("REJECT", e.Miner.User(), 0, 0, e.Error)
+}
+
+func (l *shareLogSink) writeLine(kind, user string, diff uint64, latency uint16, reason string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if strings.TrimSpace(l.path) == "" {
+		return
+	}
+	if l.file == nil {
+		file, err := os.OpenFile(l.path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
+		if err != nil {
+			return
+		}
+		l.file = file
+	}
+	var builder strings.Builder
+	builder.WriteString(time.Now().UTC().Format(time.RFC3339))
+	builder.WriteByte(' ')
+	builder.WriteString(kind)
+	builder.WriteString("  ")
+	builder.WriteString(user)
+	switch kind {
+	case "ACCEPT":
+		builder.WriteString("  diff=")
+		builder.WriteString(formatUint(diff))
+		builder.WriteString("  latency=")
+		builder.WriteString(formatUint(uint64(latency)))
+		builder.WriteString("ms")
+	case "REJECT":
+		builder.WriteString("  reason=\"")
+		builder.WriteString(reason)
+		builder.WriteString("\"")
+	}
+	builder.WriteByte('\n')
+	_, _ = l.file.WriteString(builder.String())
+}
diff --git a/sharelog_test.go b/sharelog_test.go
new file mode 100644
index 0000000..dc847c1
--- /dev/null
+++ b/sharelog_test.go
@@ -0,0 +1,46 @@
+package proxy
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestProxy_ShareLog_WritesOutcomeLines(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "shares.log")
+
+	cfg := &Config{
+		Mode:         "nicehash",
+		Workers:      WorkersByRigID,
+		ShareLogFile: path,
+		Bind:         []BindAddr{{Host: "127.0.0.1", Port: 3333}},
+		Pools:        []PoolConfig{{URL: "pool.example:3333", Enabled: true}},
+	}
+	p, result := New(cfg)
+	if !result.OK {
+		t.Fatalf("expected valid proxy, got error: %v", result.Error)
+	}
+
+	miner := &Miner{
+		user:  "WALLET",
+		conn:  noopConn{},
+		state: MinerStateReady,
+	}
+	p.events.Dispatch(Event{Type: EventAccept, Miner: miner, Diff: 1234, Latency: 56})
+	p.events.Dispatch(Event{Type: EventReject, Miner: miner, Error: "Invalid nonce"})
+	p.Stop()
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read share log: %v", err)
+	}
+	text := string(data)
+	if !strings.Contains(text, "ACCEPT  WALLET  diff=1234  latency=56ms") {
+		t.Fatalf("expected ACCEPT line, got %q", text)
+	}
+	if !strings.Contains(text, "REJECT  WALLET  reason=\"Invalid nonce\"") {
+		t.Fatalf("expected REJECT line, got %q", text)
+	}
+}
diff --git a/state_impl.go b/state_impl.go
index 5688603..9296562 100644
--- a/state_impl.go
+++ b/state_impl.go
@@ -48,6 +48,7 @@ func New(cfg *Config) (*Proxy, Result) {
 		customDiffBuckets: NewCustomDiffBuckets(cfg.CustomDiffStats),
 		rateLimit:         NewRateLimiter(cfg.RateLimit),
 		accessLog:         newAccessLogSink(cfg.AccessLogFile),
+		shareLog:          newShareLogSink(cfg.ShareLogFile),
 		done:              make(chan struct{}),
 	}
 	p.workers.bindEvents(p.events)
@@ -61,6 +62,10 @@ func New(cfg *Config) (*Proxy, Result) {
 	p.events.Subscribe(EventClose, p.stats.OnClose)
 	p.events.Subscribe(EventAccept, p.stats.OnAccept)
 	p.events.Subscribe(EventReject, p.stats.OnReject)
+	if p.shareLog != nil {
+		p.events.Subscribe(EventAccept, p.shareLog.OnAccept)
+		p.events.Subscribe(EventReject, p.shareLog.OnReject)
+	}
 	if p.customDiffBuckets != nil {
 		p.events.Subscribe(EventAccept, p.customDiffBuckets.OnAccept)
 		p.events.Subscribe(EventReject, p.customDiffBuckets.OnReject)
@@ -260,6 +265,9 @@ func (p *Proxy) Stop() {
 		if p.accessLog != nil {
 			p.accessLog.Close()
 		}
+		if p.shareLog != nil {
+			p.shareLog.Close()
+		}
 	})
 }
 
@@ -313,6 +321,9 @@ func (p *Proxy) Reload(cfg *Config) {
 	if p.accessLog != nil {
 		p.accessLog.SetPath(cfg.AccessLogFile)
 	}
+	if p.shareLog != nil {
+		p.shareLog.SetPath(cfg.ShareLogFile)
+	}
 }
 
 func (p *Proxy) acceptMiner(conn net.Conn, localPort uint16) {