diff --git a/authenticate/config.go b/authenticate/config.go
index b0ed926f8..e3eedbeaf 100644
--- a/authenticate/config.go
+++ b/authenticate/config.go
@@ -9,6 +9,7 @@ import (
 type authenticateConfig struct {
 	getIdentityProvider func(options *config.Options, idpID string) (identity.Authenticator, error)
 	profileTrimFn       func(*identitypb.Profile)
+	authEventFn         AuthEventFn
 }
 
 // An Option customizes the Authenticate config.
@@ -36,3 +37,10 @@ func WithProfileTrimFn(profileTrimFn func(*identitypb.Profile)) Option {
 		cfg.profileTrimFn = profileTrimFn
 	}
 }
+
+// WithOnAuthenticationEventHook sets the authEventFn function in the config
+func WithOnAuthenticationEventHook(fn AuthEventFn) Option {
+	return func(cfg *authenticateConfig) {
+		cfg.authEventFn = fn
+	}
+}
diff --git a/authenticate/events.go b/authenticate/events.go
new file mode 100644
index 000000000..cdb251ed1
--- /dev/null
+++ b/authenticate/events.go
@@ -0,0 +1,101 @@
+package authenticate
+
+import (
+	"context"
+	"net/http"
+	"net/url"
+
+	"github.com/pomerium/pomerium/internal/httputil"
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/pomerium/pomerium/internal/urlutil"
+	"github.com/pomerium/pomerium/pkg/grpc/identity"
+	"github.com/pomerium/pomerium/pkg/hpke"
+)
+
+// AuthEventKind is the type of an authentication event
+type AuthEventKind string
+
+const (
+	// AuthEventSignInRequest is an authentication event for a sign in request before IdP redirect
+	AuthEventSignInRequest AuthEventKind = "sign_in_request"
+	// AuthEventSignInComplete is an authentication event for a sign in request after IdP redirect
+	AuthEventSignInComplete AuthEventKind = "sign_in_complete"
+)
+
+// AuthEvent is a log event for an authentication event
+type AuthEvent struct {
+	// Event is the type of authentication event
+	Event AuthEventKind
+	// IP is the IP address of the client
+	IP string
+	// Version is the version of the Pomerium client
+	Version string
+	// RequestUUID is the UUID of the request
+	RequestUUID string
+	// PubKey is the public key of the client
+	PubKey string
+	// UID is the IdP user ID of the user
+	UID *string
+	// Email is the email of the user
+	Email *string
+	// Domain is the domain of the request (for sign in complete events)
+	Domain *string
+}
+
+// AuthEventFn is a function that handles an authentication event
+type AuthEventFn func(context.Context, AuthEvent)
+
+func (a *Authenticate) logAuthenticateEvent(r *http.Request, profile *identity.Profile) {
+	if a.cfg.authEventFn == nil {
+		return
+	}
+
+	state := a.state.Load()
+	ctx := r.Context()
+	pub, params, err := hpke.DecryptURLValues(state.hpkePrivateKey, r.Form)
+	if err != nil {
+		log.Warn(ctx).Err(err).Msg("log authenticate event: failed to decrypt request params")
+	}
+
+	evt := AuthEvent{
+		IP:          httputil.GetClientIP(r),
+		Version:     params.Get(urlutil.QueryVersion),
+		RequestUUID: params.Get(urlutil.QueryRequestUUID),
+		PubKey:      pub.String(),
+	}
+
+	if uid := getUserClaim(profile, "sub"); uid != nil {
+		evt.UID = uid
+	}
+	if email := getUserClaim(profile, "email"); email != nil {
+		evt.Email = email
+	}
+
+	if evt.UID != nil {
+		evt.Event = AuthEventSignInComplete
+	} else {
+		evt.Event = AuthEventSignInRequest
+	}
+
+	if redirectURL, err := url.Parse(params.Get(urlutil.QueryRedirectURI)); err == nil {
+		domain := redirectURL.Hostname()
+		evt.Domain = &domain
+	}
+
+	a.cfg.authEventFn(ctx, evt)
+}
+
+func getUserClaim(profile *identity.Profile, field string) *string {
+	if profile == nil {
+		return nil
+	}
+	if profile.Claims == nil {
+		return nil
+	}
+	val, ok := profile.Claims.Fields[field]
+	if !ok || val == nil {
+		return nil
+	}
+	txt := val.GetStringValue()
+	return &txt
+}
diff --git a/authenticate/handlers.go b/authenticate/handlers.go
index 5ea9c5c07..9b0aba49c 100644
--- a/authenticate/handlers.go
+++ b/authenticate/handlers.go
@@ -216,6 +216,8 @@ func (a *Authenticate) SignIn(w http.ResponseWriter, r *http.Request) error {
 		a.cfg.profileTrimFn(profile)
 	}
 
+	a.logAuthenticateEvent(r, profile)
+
 	redirectTo, err := urlutil.CallbackURL(state.hpkePrivateKey, proxyPublicKey, requestParams, profile)
 	if err != nil {
 		return httputil.NewError(http.StatusInternalServerError, err)
@@ -315,6 +317,8 @@ func (a *Authenticate) reauthenticateOrFail(w http.ResponseWriter, r *http.Reque
 		return err
 	}
 
+	a.logAuthenticateEvent(r, nil)
+
 	state.sessionStore.ClearSession(w, r)
 	redirectURL := state.redirectURL.ResolveReference(r.URL)
 	nonce := csrf.Token(r)
diff --git a/internal/httputil/ip.go b/internal/httputil/ip.go
new file mode 100644
index 000000000..9f93cf8e7
--- /dev/null
+++ b/internal/httputil/ip.go
@@ -0,0 +1,14 @@
+package httputil
+
+import (
+	"net/http"
+	"strings"
+)
+
+// GetClientIP returns the client IP address from the request.
+func GetClientIP(r *http.Request) string {
+	if clientIP := r.Header.Get("X-Forwarded-For"); clientIP != "" {
+		return strings.Split(clientIP, ",")[0]
+	}
+	return strings.Split(r.RemoteAddr, ":")[0]
+}
diff --git a/internal/urlutil/known.go b/internal/urlutil/known.go
index e7833e098..20d1cd03d 100644
--- a/internal/urlutil/known.go
+++ b/internal/urlutil/known.go
@@ -4,8 +4,12 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"os"
+	"runtime"
+	"strings"
 	"time"
 
+	"github.com/google/uuid"
 	"google.golang.org/protobuf/encoding/protojson"
 
 	"github.com/pomerium/pomerium/internal/version"
@@ -21,6 +25,15 @@ const DefaultDeviceType = "any"
 
 const signInExpiry = time.Minute * 5
 
+var (
+	pomeriumRuntime = os.Getenv("POMERIUM_RUNTIME")
+	pomeriumArch    = fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH)
+)
+
+func versionStr() string {
+	return strings.Join([]string{version.FullVersion(), pomeriumArch, pomeriumRuntime}, " ")
+}
+
 // CallbackURL builds the callback URL using an HPKE encrypted query string.
 func CallbackURL(
 	authenticatePrivateKey *hpke.PrivateKey,
@@ -59,7 +72,7 @@ func CallbackURL(
 		return "", fmt.Errorf("error marshaling identity profile: %w", err)
 	}
 	callbackParams.Set(QueryIdentityProfile, string(rawProfile))
-	callbackParams.Set(QueryVersion, version.FullVersion())
+	callbackParams.Set(QueryVersion, versionStr())
 
 	BuildTimeParameters(callbackParams, signInExpiry)
 
@@ -99,7 +112,8 @@ func SignInURL(
 	q := signInURL.Query()
 	q.Set(QueryRedirectURI, redirectURL.String())
 	q.Set(QueryIdentityProviderID, idpID)
-	q.Set(QueryVersion, version.FullVersion())
+	q.Set(QueryVersion, versionStr())
+	q.Set(QueryRequestUUID, uuid.NewString())
 	BuildTimeParameters(q, signInExpiry)
 	q, err := hpke.EncryptURLValues(senderPrivateKey, authenticatePublicKey, q)
 	if err != nil {
@@ -119,7 +133,7 @@ func SignOutURL(r *http.Request, authenticateURL *url.URL, key []byte) string {
 	if redirectURI, ok := RedirectURL(r); ok {
 		q.Set(QueryRedirectURI, redirectURI)
 	}
-	q.Set(QueryVersion, version.FullVersion())
+	q.Set(QueryVersion, versionStr())
 	u.RawQuery = q.Encode()
 	return NewSignedURL(key, u).Sign().String()
 }
diff --git a/internal/urlutil/query_params.go b/internal/urlutil/query_params.go
index 15a0c850a..ac5a127bc 100644
--- a/internal/urlutil/query_params.go
+++ b/internal/urlutil/query_params.go
@@ -19,6 +19,7 @@ const (
 	QuerySessionEncrypted   = "pomerium_session_encrypted"
 	QuerySessionState       = "pomerium_session_state"
 	QueryVersion            = "pomerium_version"
+	QueryRequestUUID        = "pomerium_request_uuid"
 )
 
 // URL signature based query params used for verifying the authenticity of a URL.