diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8ab4eac7..47dd5767 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,15 +3,20 @@
 ## Unreleased
 
 ### Added
+- Added separate `Meta`, `SealedMeta` and `ObservableMutableMeta` builders.
 
 ### Changed
 - Kotlin 1.9
+- `MutableMeta` builder now returns a simplified version of meta that does not hold listeners. 
+- Ktor-io is replaced with kotlinx-io.
+- More concise names for read/write methods in IO.
 
 ### Deprecated
 
 ### Removed
 
 ### Fixed
+- Memory leak in SealedMeta builder
 
 ### Security
 
diff --git a/build.gradle.kts b/build.gradle.kts
index bbab94eb..f15d4a8b 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -9,7 +9,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.6.2"
+    version = "0.6.3-dev-1"
 }
 
 subprojects {
diff --git a/dataforge-io/dataforge-io-yaml/src/commonMain/kotlin/space/kscience/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt b/dataforge-io/dataforge-io-yaml/src/commonMain/kotlin/space/kscience/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
index 736f3306..f999ad5b 100644
--- a/dataforge-io/dataforge-io-yaml/src/commonMain/kotlin/space/kscience/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
+++ b/dataforge-io/dataforge-io-yaml/src/commonMain/kotlin/space/kscience/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
@@ -19,7 +19,7 @@ public class FrontMatterEnvelopeFormat(
     private val metaFormatFactory: MetaFormatFactory = YamlMetaFormat,
 ) : EnvelopeFormat {
 
-    override fun readObject(binary: Binary): Envelope = binary.read {
+    override fun readFrom(binary: Binary): Envelope = binary.read {
         var offset = 0
 
         offset += discardWithSeparator(
@@ -39,20 +39,20 @@ public class FrontMatterEnvelopeFormat(
 
         offset += discardLine()
 
-        val meta = readMetaFormat.readObject(packet.asBinary())
+        val meta = readMetaFormat.readFrom(packet.asBinary())
         Envelope(meta, binary.view(offset))
     }
 
-    override fun readObject(source: Source): Envelope = readObject(source.readBinary())
+    override fun readFrom(source: Source): Envelope = readFrom(source.readBinary())
 
-    override fun writeObject(
+    override fun writeTo(
         sink: Sink,
         obj: Envelope,
     ) {
         val metaFormat = metaFormatFactory.build(io.context, meta)
         val formatSuffix = if (metaFormat is YamlMetaFormat) "" else metaFormatFactory.shortName
         sink.writeString("$SEPARATOR${formatSuffix}\r\n")
-        metaFormat.run { metaFormat.writeObject(sink, obj.meta) }
+        metaFormat.run { metaFormat.writeTo(sink, obj.meta) }
         sink.writeString("$SEPARATOR\r\n")
         //Printing data
         obj.data?.let { data ->
@@ -83,15 +83,15 @@ public class FrontMatterEnvelopeFormat(
 
         private val default by lazy { build(Global, Meta.EMPTY) }
 
-        override fun readObject(binary: Binary): Envelope = default.readObject(binary)
+        override fun readFrom(binary: Binary): Envelope = default.readFrom(binary)
 
-        override fun writeObject(
+        override fun writeTo(
             sink: Sink,
             obj: Envelope,
-        ): Unit = default.writeObject(sink, obj)
+        ): Unit = default.writeTo(sink, obj)
 
 
-        override fun readObject(source: Source): Envelope = default.readObject(source)
+        override fun readFrom(source: Source): Envelope = default.readFrom(source)
 
     }
 }
\ No newline at end of file
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/EnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/EnvelopeFormat.kt
index d748d9f8..8a2a09b4 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/EnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/EnvelopeFormat.kt
@@ -15,7 +15,7 @@ public interface EnvelopeFormat : IOFormat<Envelope> {
     override val type: KType get() = typeOf<Envelope>()
 }
 
-public fun EnvelopeFormat.read(input: Source): Envelope = readObject(input)
+public fun EnvelopeFormat.read(input: Source): Envelope = readFrom(input)
 
 @Type(ENVELOPE_FORMAT_TYPE)
 public interface EnvelopeFormatFactory : IOFormatFactory<Envelope>, EnvelopeFormat {
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/IOFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/IOFormat.kt
index d0d00a9a..e51aa40a 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/IOFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/IOFormat.kt
@@ -23,9 +23,9 @@ public interface IOReader<out T> {
      */
     public val type: KType
 
-    public fun readObject(source: Source): T
+    public fun readFrom(source: Source): T
 
-    public fun readObject(binary: Binary): T = binary.read { readObject(this) }
+    public fun readFrom(binary: Binary): T = binary.read { readFrom(this) }
 
     public companion object {
         /**
@@ -34,9 +34,9 @@ public interface IOReader<out T> {
         public val binary: IOReader<Binary> = object : IOReader<Binary> {
             override val type: KType = typeOf<Binary>()
 
-            override fun readObject(source: Source): Binary = source.readByteArray().asBinary()
+            override fun readFrom(source: Source): Binary = source.readByteArray().asBinary()
 
-            override fun readObject(binary: Binary): Binary = binary
+            override fun readFrom(binary: Binary): Binary = binary
         }
     }
 }
@@ -44,11 +44,11 @@ public interface IOReader<out T> {
 public inline fun <reified T> IOReader(crossinline read: Source.() -> T): IOReader<T> = object : IOReader<T> {
     override val type: KType = typeOf<T>()
 
-    override fun readObject(source: Source): T = source.read()
+    override fun readFrom(source: Source): T = source.read()
 }
 
 public fun interface IOWriter<in T> {
-    public fun writeObject(sink: Sink, obj: T)
+    public fun writeTo(sink: Sink, obj: T)
 }
 
 /**
@@ -56,21 +56,20 @@ public fun interface IOWriter<in T> {
  */
 public interface IOFormat<T> : IOReader<T>, IOWriter<T>
 
-public fun <T : Any> Source.readObject(format: IOReader<T>): T = format.readObject(this@readObject)
-
-public fun <T : Any> IOFormat<T>.readObjectFrom(binary: Binary): T = binary.read {
-    readObject(this)
-}
+public fun <T : Any> Source.readWith(format: IOReader<T>): T = format.readFrom(this)
 
 /**
  * Read given binary as an object using given format
  */
 public fun <T : Any> Binary.readWith(format: IOReader<T>): T = read {
-    readObject(format)
+    readWith(format)
 }
 
-public fun <T : Any> Sink.writeObject(format: IOWriter<T>, obj: T): Unit =
-    format.writeObject(this@writeObject, obj)
+/**
+ * Write an object to the [Sink] with given [format]
+ */
+public fun <T : Any> Sink.writeWith(format: IOWriter<T>, obj: T): Unit =
+    format.writeTo(this, obj)
 
 
 @Type(IO_FORMAT_TYPE)
@@ -87,7 +86,7 @@ public interface IOFormatFactory<T : Any> : Factory<IOFormat<T>>, Named {
     }
 }
 
-public fun <T : Any> Binary(obj: T, format: IOWriter<T>): Binary = Binary { format.writeObject(this, obj) }
+public fun <T : Any> Binary(obj: T, format: IOWriter<T>): Binary = Binary { format.writeTo(this, obj) }
 
 public object DoubleIOFormat : IOFormat<Double>, IOFormatFactory<Double> {
     override fun build(context: Context, meta: Meta): IOFormat<Double> = this
@@ -96,9 +95,9 @@ public object DoubleIOFormat : IOFormat<Double>, IOFormatFactory<Double> {
 
     override val type: KType get() = typeOf<Double>()
 
-    override fun writeObject(sink: Sink, obj: Double) {
+    override fun writeTo(sink: Sink, obj: Double) {
         sink.writeLong(obj.toBits())
     }
 
-    override fun readObject(source: Source): Double = Double.fromBits(source.readLong())
+    override fun readFrom(source: Source): Double = Double.fromBits(source.readLong())
 }
\ No newline at end of file
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/MetaFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/MetaFormat.kt
index 25eb8f2f..dcffd657 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/MetaFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/MetaFormat.kt
@@ -23,11 +23,11 @@ public interface MetaFormat : IOFormat<Meta> {
 
     override val type: KType get() = typeOf<Meta>()
 
-    override fun writeObject(sink: Sink, obj: Meta) {
+    override fun writeTo(sink: Sink, obj: Meta) {
         writeMeta(sink, obj, null)
     }
 
-    override fun readObject(source: Source): Meta = readMeta(source)
+    override fun readFrom(source: Source): Meta = readMeta(source)
 
     public fun writeMeta(
         sink: Sink,
@@ -57,13 +57,13 @@ public interface MetaFormatFactory : IOFormatFactory<Meta>, MetaFormat {
 
 public fun Meta.toString(format: MetaFormat): String = ByteArray {
     format.run {
-        writeObject(this@ByteArray, this@toString)
+        writeTo(this@ByteArray, this@toString)
     }
 }.decodeToString()
 
 public fun Meta.toString(formatFactory: MetaFormatFactory): String = toString(formatFactory.build(Global, Meta.EMPTY))
 
-public fun MetaFormat.parse(str: String): Meta = readObject(StringSource(str).buffered())
+public fun MetaFormat.parse(str: String): Meta = readFrom(StringSource(str).buffered())
 
 public fun MetaFormatFactory.parse(str: String, formatMeta: Meta): Meta = build(Global, formatMeta).parse(str)
 
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaggedEnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaggedEnvelopeFormat.kt
index 763c90b1..13b14595 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaggedEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaggedEnvelopeFormat.kt
@@ -43,7 +43,7 @@ public class TaggedEnvelopeFormat(
         write(END_SEQUENCE)
     }
 
-    override fun writeObject(
+    override fun writeTo(
         sink: Sink,
         obj: Envelope,
     ) {
@@ -65,7 +65,7 @@ public class TaggedEnvelopeFormat(
      * @param source an input to read from
      * @param formats a collection of meta formats to resolve
      */
-    override fun readObject(source: Source): Envelope {
+    override fun readFrom(source: Source): Envelope {
         val tag = source.readTag(this.version)
 
         val metaFormat = io.resolveMetaFormat(tag.metaFormatKey)
@@ -73,14 +73,14 @@ public class TaggedEnvelopeFormat(
 
         val metaBinary = source.readBinary(tag.metaSize.toInt())
 
-        val meta: Meta = metaFormat.readObjectFrom(metaBinary)
+        val meta: Meta = metaFormat.readFrom(metaBinary)
 
         val data = source.readBinary(tag.dataSize.toInt())
 
         return SimpleEnvelope(meta, data)
     }
 
-    override fun readObject(binary: Binary): Envelope = binary.read {
+    override fun readFrom(binary: Binary): Envelope = binary.read {
         val tag = readTag(version)
 
         val metaFormat = io.resolveMetaFormat(tag.metaFormatKey)
@@ -88,7 +88,7 @@ public class TaggedEnvelopeFormat(
 
         val metaBinary = readBinary(tag.metaSize.toInt())
 
-        val meta: Meta = metaFormat.readObjectFrom(metaBinary)
+        val meta: Meta = metaFormat.readFrom(metaBinary)
 
 
         SimpleEnvelope(meta, binary.view((version.tagSize + tag.metaSize).toInt(), tag.dataSize.toInt()))
@@ -154,17 +154,17 @@ public class TaggedEnvelopeFormat(
 
         private val default by lazy { build(Global, Meta.EMPTY) }
 
-        override fun readObject(binary: Binary): Envelope =
-            default.run { readObject(binary) }
+        override fun readFrom(binary: Binary): Envelope =
+            default.run { readFrom(binary) }
 
-        override fun writeObject(
+        override fun writeTo(
             sink: Sink,
             obj: Envelope,
         ): Unit = default.run {
-            writeObject(sink, obj)
+            writeTo(sink, obj)
         }
 
-        override fun readObject(source: Source): Envelope = default.readObject(source)
+        override fun readFrom(source: Source): Envelope = default.readFrom(source)
     }
 
 }
\ No newline at end of file
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaglessEnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaglessEnvelopeFormat.kt
index 2d49a3c0..011aa2c6 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaglessEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/TaglessEnvelopeFormat.kt
@@ -28,7 +28,7 @@ public class TaglessEnvelopeFormat(
 //        writeFully("#? $key: $value;\r\n".encodeToByteArray())
 //    }
 
-    override fun writeObject(
+    override fun writeTo(
         sink: Sink,
         obj: Envelope,
     ) {
@@ -54,7 +54,7 @@ public class TaglessEnvelopeFormat(
         }
     }
 
-    override fun readObject(source: Source): Envelope {
+    override fun readFrom(source: Source): Envelope {
         //read preamble
         source.discardWithSeparator(
             TAGLESS_ENVELOPE_HEADER,
@@ -132,16 +132,16 @@ public class TaglessEnvelopeFormat(
 
         private val default by lazy { build(Global, Meta.EMPTY) }
 
-        override fun readObject(binary: Binary): Envelope = default.run { readObject(binary) }
+        override fun readFrom(binary: Binary): Envelope = default.run { readFrom(binary) }
 
-        override fun writeObject(
+        override fun writeTo(
             sink: Sink,
             obj: Envelope,
         ): Unit = default.run {
-            writeObject(sink, obj)
+            writeTo(sink, obj)
         }
 
-        override fun readObject(source: Source): Envelope = default.readObject(source)
+        override fun readFrom(source: Source): Envelope = default.readFrom(source)
 
         override fun peekFormat(io: IOPlugin, binary: Binary): EnvelopeFormat? {
             return try {
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/ioMisc.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/ioMisc.kt
index ff7f985d..4e4a7ff7 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/ioMisc.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/ioMisc.kt
@@ -57,7 +57,7 @@ public fun IOPlugin.readEnvelope(
     binary: Binary,
     readNonEnvelopes: Boolean = false,
     formatPicker: IOPlugin.(Binary) -> EnvelopeFormat? = IOPlugin::peekBinaryEnvelopeFormat,
-): Envelope = formatPicker(binary)?.readObject(binary) ?: if (readNonEnvelopes) {
+): Envelope = formatPicker(binary)?.readFrom(binary) ?: if (readNonEnvelopes) {
     // if no format accepts file, read it as binary
     Envelope(Meta.EMPTY, binary)
 } else error("Can't infer format for $binary")
diff --git a/dataforge-io/src/jvmMain/kotlin/space/kscience/dataforge/io/fileIO.kt b/dataforge-io/src/jvmMain/kotlin/space/kscience/dataforge/io/fileIO.kt
index 3cc81b32..c15280f3 100644
--- a/dataforge-io/src/jvmMain/kotlin/space/kscience/dataforge/io/fileIO.kt
+++ b/dataforge-io/src/jvmMain/kotlin/space/kscience/dataforge/io/fileIO.kt
@@ -78,7 +78,7 @@ public fun Path.rewrite(block: Sink.() -> Unit): Unit {
 }
 
 @DFExperimental
-public fun EnvelopeFormat.readFile(path: Path): Envelope = readObject(path.asBinary())
+public fun EnvelopeFormat.readFile(path: Path): Envelope = readFrom(path.asBinary())
 
 /**
  * Resolve IOFormat based on type
@@ -238,7 +238,7 @@ public fun IOPlugin.writeEnvelopeFile(
     envelopeFormat: EnvelopeFormat = TaggedEnvelopeFormat,
 ) {
     path.rewrite {
-        envelopeFormat.writeObject(this, envelope)
+        envelopeFormat.writeTo(this, envelope)
     }
 }
 
diff --git a/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/FileWorkspaceCache.kt b/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/FileWorkspaceCache.kt
index a637ad97..279e61a2 100644
--- a/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/FileWorkspaceCache.kt
+++ b/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/FileWorkspaceCache.kt
@@ -27,10 +27,10 @@ public class JsonIOFormat<T : Any>(override val type: KType) : IOFormat<T> {
     @Suppress("UNCHECKED_CAST")
     private val serializer: KSerializer<T> = serializer(type) as KSerializer<T>
 
-    override fun readObject(input: Source): T = Json.decodeFromString(serializer, input.readString())
+    override fun readFrom(source: Source): T = Json.decodeFromString(serializer, source.readString())
 
-    override fun writeObject(output: Sink, obj: T) {
-        output.writeString(Json.encodeToString(serializer, obj))
+    override fun writeTo(sink: Sink, obj: T) {
+        sink.writeString(Json.encodeToString(serializer, obj))
     }
 }
 
@@ -40,10 +40,10 @@ public class ProtobufIOFormat<T : Any>(override val type: KType) : IOFormat<T> {
     @Suppress("UNCHECKED_CAST")
     private val serializer: KSerializer<T> = serializer(type) as KSerializer<T>
 
-    override fun readObject(input: Source): T = ProtoBuf.decodeFromByteArray(serializer, input.readByteArray())
+    override fun readFrom(source: Source): T = ProtoBuf.decodeFromByteArray(serializer, source.readByteArray())
 
-    override fun writeObject(output: Sink, obj: T) {
-        output.write(ProtoBuf.encodeToByteArray(serializer, obj))
+    override fun writeTo(sink: Sink, obj: T) {
+        sink.write(ProtoBuf.encodeToByteArray(serializer, obj))
     }
 }
 
@@ -85,7 +85,7 @@ public class FileWorkspaceCache(public val cacheDirectory: Path) : WorkspaceCach
                     val envelope = Envelope {
                         meta = data.meta
                         data {
-                            writeObject(format, result)
+                            writeWith(format, result)
                         }
                     }
                     io.writeEnvelopeFile(path, envelope)
diff --git a/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/zipData.kt b/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/zipData.kt
index d23753a2..466552c2 100644
--- a/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/zipData.kt
+++ b/dataforge-workspace/src/jvmMain/kotlin/space/kscience/dataforge/workspace/zipData.kt
@@ -28,7 +28,7 @@ private suspend fun <T : Any> ZipOutputStream.writeNode(
 
             //TODO remove additional copy
             val bytes = ByteArray {
-                writeObject(envelopeFormat, envelope)
+                writeWith(envelopeFormat, envelope)
             }
             write(bytes)
 
diff --git a/dataforge-workspace/src/jvmTest/kotlin/space/kscience/dataforge/workspace/FileDataTest.kt b/dataforge-workspace/src/jvmTest/kotlin/space/kscience/dataforge/workspace/FileDataTest.kt
index 313ea82e..451c76f4 100644
--- a/dataforge-workspace/src/jvmTest/kotlin/space/kscience/dataforge/workspace/FileDataTest.kt
+++ b/dataforge-workspace/src/jvmTest/kotlin/space/kscience/dataforge/workspace/FileDataTest.kt
@@ -9,7 +9,10 @@ import kotlinx.io.writeString
 import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.context.Global
 import space.kscience.dataforge.data.*
-import space.kscience.dataforge.io.*
+import space.kscience.dataforge.io.Envelope
+import space.kscience.dataforge.io.IOFormat
+import space.kscience.dataforge.io.io
+import space.kscience.dataforge.io.readEnvelopeFile
 import space.kscience.dataforge.io.yaml.YamlPlugin
 import space.kscience.dataforge.meta.get
 import space.kscience.dataforge.misc.DFExperimental
@@ -39,11 +42,11 @@ class FileDataTest {
     object StringIOFormat : IOFormat<String> {
         override val type: KType get() = typeOf<String>()
 
-        override fun writeObject(output: Sink, obj: String) {
-            output.writeString(obj)
+        override fun writeTo(sink: Sink, obj: String) {
+            sink.writeString(obj)
         }
 
-        override fun readObject(input: Source): String = input.readString()
+        override fun readFrom(source: Source): String = source.readString()
     }
 
     @Test