diff --git a/filter.go b/filter.go
new file mode 100644
index 0000000..b8edc16
--- /dev/null
+++ b/filter.go
@@ -0,0 +1,96 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"fiatjaf.com/nostr"
+	"github.com/mailru/easyjson"
+	"github.com/urfave/cli/v3"
+)
+
+var filter = &cli.Command{
+	Name:  "filter",
+	Usage: "applies an event filter to an event to see if it matches.",
+	Description: `
+example:
+		echo '{"kind": 1, "content": "hello"}' | nak filter -k 1
+		nak filter '{"kind": 1, "content": "hello"}' -k 1
+		nak filter '{"kind": 1, "content": "hello"}' '{"kinds": [1]}' -k 0
+`,
+	DisableSliceFlagSeparator: true,
+	Flags:                     reqFilterFlags,
+	ArgsUsage:                 "[event_json] [base_filter_json]",
+	Action: func(ctx context.Context, c *cli.Command) error {
+		args := c.Args().Slice()
+
+		var baseFilter nostr.Filter
+		var baseEvent nostr.Event
+
+		if len(args) == 2 {
+			// two arguments: first is event, second is base filter
+			if err := easyjson.Unmarshal([]byte(args[0]), &baseEvent); err != nil {
+				return fmt.Errorf("invalid base event: %w", err)
+			}
+			if err := easyjson.Unmarshal([]byte(args[1]), &baseFilter); err != nil {
+				return fmt.Errorf("invalid base filter: %w", err)
+			}
+		} else if len(args) == 1 {
+			if isPiped() {
+				// one argument + stdin: argument is base filter
+				if err := easyjson.Unmarshal([]byte(args[0]), &baseFilter); err != nil {
+					return fmt.Errorf("invalid base filter: %w", err)
+				}
+			} else {
+				// one argument, no stdin: argument is event
+				if err := easyjson.Unmarshal([]byte(args[0]), &baseEvent); err != nil {
+					return fmt.Errorf("invalid base event: %w", err)
+				}
+			}
+		}
+
+		// apply flags to filter
+		if err := applyFlagsToFilter(c, &baseFilter); err != nil {
+			return err
+		}
+
+		// if there is no stdin we'll still get an empty object here
+		for evtj := range getJsonsOrBlank() {
+			var evt nostr.Event
+			if err := easyjson.Unmarshal([]byte(evtj), &evt); err != nil {
+				ctx = lineProcessingError(ctx, "invalid event: %s", err)
+				continue
+			}
+
+			// merge that with the base event
+			if evt.ID == nostr.ZeroID {
+				evt.ID = baseEvent.ID
+			}
+			if evt.PubKey == nostr.ZeroPK {
+				evt.PubKey = baseEvent.PubKey
+			}
+			if evt.Sig == [64]byte{} {
+				evt.Sig = baseEvent.Sig
+			}
+			if evt.Content == "" {
+				evt.Content = baseEvent.Content
+			}
+			if len(evt.Tags) == 0 {
+				evt.Tags = baseEvent.Tags
+			}
+			if evt.CreatedAt == 0 {
+				evt.CreatedAt = baseEvent.CreatedAt
+			}
+
+			if baseFilter.Matches(evt) {
+				stdout(evt)
+			} else {
+				fmt.Println(baseFilter.LimitZero)
+				logverbose("event %s didn't match %s", evt, baseFilter)
+			}
+		}
+
+		exitIfLineProcessingError(ctx)
+		return nil
+	},
+}
diff --git a/main.go b/main.go
index 5f5e04b..9545804 100644
--- a/main.go
+++ b/main.go
@@ -27,6 +27,7 @@ var app = &cli.Command{
 	Commands: []*cli.Command{
 		event,
 		req,
+		filter,
 		fetch,
 		count,
 		decode,