diff --git a/README.md b/README.md
index 2e9476f..b408f3f 100644
--- a/README.md
+++ b/README.md
@@ -30,8 +30,10 @@ For non-WAL databases, `NORMAL` locking mode can be activated with
 [`PRAGMA locking_mode=NORMAL`](https://www.sqlite.org/pragma.html#pragma_locking_mode).
 
 Because connection pooling is incompatible with `EXCLUSIVE` locking mode,
-the `database/sql` driver defaults to `NORMAL` locking mode,
-and WAL databases are not supported.
+the `database/sql` driver defaults to `NORMAL` locking mode.
+To open WAL databases, or use `EXCLUSIVE` locking mode,
+disable connection pooling by calling
+[`db.SetMaxOpenConns(1)`](https://pkg.go.dev/database/sql#DB.SetMaxOpenConns).
 
 #### Open File Description Locks
 
diff --git a/conn.go b/conn.go
index 60b1ec6..2bb2d42 100644
--- a/conn.go
+++ b/conn.go
@@ -3,6 +3,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql/driver"
+	"errors"
 	"fmt"
 	"net/url"
 	"runtime"
@@ -91,8 +92,11 @@ func (c *Conn) openDB(filename string, flags OpenFlag) (uint32, error) {
 		pragmaPtr := c.arena.string(pragmas.String())
 		r := c.call(c.api.exec, uint64(handle), uint64(pragmaPtr), 0, 0, 0)
 		if err := c.module.error(r[0], handle, pragmas.String()); err != nil {
+			if errors.Is(err, ERROR) {
+				err = fmt.Errorf("sqlite3: invalid _pragma: %w", err)
+			}
 			c.closeDB(handle)
-			return 0, fmt.Errorf("sqlite3: invalid _pragma: %w", err)
+			return 0, err
 		}
 	}
 	return handle, nil
diff --git a/driver/driver.go b/driver/driver.go
index 0638056..06dc4df 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -96,6 +96,7 @@ var (
 	// Ensure these interfaces are implemented:
 	_ driver.ExecerContext = conn{}
 	_ driver.ConnBeginTx   = conn{}
+	_ driver.Validator     = conn{}
 	_ sqlite3.DriverConn   = conn{}
 )
 
@@ -103,6 +104,11 @@ func (c conn) Close() error {
 	return c.conn.Close()
 }
 
+func (c conn) IsValid() (valid bool) {
+	r, err := c.conn.Pragma("locking_mode")
+	return err == nil && len(r) == 1 && r[0] == "normal"
+}
+
 func (c conn) Begin() (driver.Tx, error) {
 	return c.BeginTx(context.Background(), driver.TxOptions{})
 }
diff --git a/embed/README.md b/embed/README.md
new file mode 100644
index 0000000..3acd5df
--- /dev/null
+++ b/embed/README.md
@@ -0,0 +1,15 @@
+# Embeddable WASM build of SQLite
+
+This folder includes an embeddable WASM build of SQLite 3.41.0 for use with
+[`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3).
+
+The following optional features are compiled in:
+- math functions
+- FTS3/4/5
+- JSON
+- R*Tree
+- GeoPoly
+
+See the [configuration options](../sqlite3/sqlite_cfg.h).
+
+Built using [`zig`](https://ziglang.org/) version 0.10.1.
\ No newline at end of file
diff --git a/embed/init.go b/embed/init.go
index 3ad54f8..da527ab 100644
--- a/embed/init.go
+++ b/embed/init.go
@@ -4,12 +4,6 @@
 // with an appropriate build of SQLite:
 //
 //	import _ "github.com/ncruces/go-sqlite3/embed"
-//
-// The following optional features are compiled in:
-// math functions, JSON, FTS3/4/5, R*Tree, GeoPoly.
-//
-// You can obtain this build of SQLite from:
-// https://github.com/ncruces/go-sqlite3/tree/main/embed
 package embed
 
 import (