diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 060e2d55..d741ca67 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -126,9 +126,9 @@ jobs:
           - stable
           - 1.65.0  # keep in sync with manifest MSRV
         args:
-          - --all-features
+          - ""
           - --no-default-features
-          - --no-default-features --features json
+          - --no-default-features --features json-core
 
     steps:
       - uses: actions/checkout@v2
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 327b14f5..f7455889 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,7 +33,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [breaking] `iter_paths`/`MiniconfIter` is now generic over the type
   to write the path into. Downstream crates should replace `iter_paths::<L, TS>()` with
   `iter_paths::<L, heapless::String<TS>>()`.
-* The `mqtt-client` feature has been renamed into `mqtt` with backward compatibility.
 * [breaking] Re-exports of `heapless` and `serde-json-core` have been removed as they are
   not needed to work with the public API.
 
diff --git a/Cargo.toml b/Cargo.toml
index 4305483b..5e4a11fe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,17 +17,20 @@ serde = { version = "1.0.120", features = ["derive"], default-features = false }
 miniconf_derive = { path = "miniconf_derive" , version = "0.6" }
 itoa = "1.0.4"
 
-serde-json-core = { git = "https://github.com/rust-embedded-community/serde-json-core.git" , optional = true}
-log = {version = "0.4", optional = true}
-heapless = { version = "0.7", features = ["serde"], optional=true }
+serde-json-core = { git = "https://github.com/rust-embedded-community/serde-json-core.git" , optional = true }
+serde_json = { version = "1.0", optional = true }
+tinyvec = { version = "1.6", optional = true }
+log = {version = "0.4", optional = true }
+heapless = { version = "0.7", optional=true }
 minimq = { version = "0.7", optional = true }
 smlang = { version = "0.6", optional = true }
 
 [features]
-default = ["mqtt"]
-json = ["dep:serde-json-core", "dep:heapless"]
-mqtt = ["dep:minimq", "dep:smlang", "dep:log", "json"]
-mqtt-client = ["mqtt"]  # backwards compat
+default = ["mqtt-client"]
+json-core = ["dep:serde-json-core"]
+json = ["dep:serde_json", "dep:tinyvec", "std"]
+std = []
+mqtt-client = ["json-core", "dep:minimq", "dep:smlang", "dep:log", "dep:heapless"]
 
 [dev-dependencies]
 machine = "0.3"
@@ -43,8 +46,8 @@ branch = "feature/0.7"
 
 [[example]]
 name = "mqtt"
-required-features = ["mqtt"]
+required-features = ["mqtt-client"]
 
 [[example]]
 name = "readback"
-required-features = ["json"]
+required-features = ["json-core"]
diff --git a/README.md b/README.md
index 80ad5185..5a5b3968 100644
--- a/README.md
+++ b/README.md
@@ -160,7 +160,10 @@ Deferred (non-atomic) access to inner elements of some types is not yet supporte
 * Tuple structs (other than [Option], [Array])
 
 ## Features
-* `mqtt` Enable the MQTT client feature. See the example in [MqttClient].
-* `json` Enable the [SerDe] implementation for the [JsonCoreSlash] style.
+* `mqtt-client` Enable the MQTT client feature. See the example in [MqttClient].
+* `json-core` Enable the [SerDe] implementation for the [JsonCoreSlash] style
+  (using `serde_json_core`).
+* `json` Enable the [SerDe] implementation for the [JsonSlash] style (using
+  `serde_json`).
 
-Both features are enabled by default.
+The `mqtt-client` and `json-core` features are enabled by default.
diff --git a/src/json.rs b/src/json.rs
index 9fff12cc..7a646d56 100644
--- a/src/json.rs
+++ b/src/json.rs
@@ -1,46 +1,31 @@
 use crate::{Error, Miniconf, SerDe};
-use serde_json_core::{de, ser};
 
 /// Marker struct for the "JSON and `/`" [SerDe] specification.
 ///
-/// Access items with `'/'` as path separator and JSON (from `serde-json-core`)
+/// Access items with `'/'` as path separator and JSON (from `serde-json`)
 /// as serialization/deserialization payload format.
-pub struct JsonCoreSlash;
+pub struct JsonSlash;
 
-impl<T> SerDe<JsonCoreSlash> for T
+impl<T> SerDe<JsonSlash> for T
 where
     T: Miniconf,
 {
     const SEPARATOR: char = '/';
-    type DeError = de::Error;
-    type SerError = ser::Error;
+    type DeError = serde_json::Error;
+    type SerError = serde_json::Error;
 
     fn set(&mut self, path: &str, data: &[u8]) -> Result<usize, Error<Self::DeError>> {
-        let mut de = de::Deserializer::new(data);
+        let mut de = serde_json::Deserializer::from_slice(data);
         self.set_path(&mut path.split(Self::SEPARATOR).skip(1), &mut de)?;
-        de.end().map_err(Error::PostDeserialization)
+        de.end()
+            .map_err(Error::PostDeserialization)
+            .map(|_| data.len())
     }
 
     fn get(&self, path: &str, data: &mut [u8]) -> Result<usize, Error<Self::SerError>> {
-        let mut ser = ser::Serializer::new(data);
+        let mut buf = std::io::Cursor::new(data);
+        let mut ser = serde_json::Serializer::new(&mut buf);
         self.get_path(&mut path.split(Self::SEPARATOR).skip(1), &mut ser)?;
-        Ok(ser.end())
-    }
-}
-
-// These allow unifying serde error information to make writing examples
-// and tests easier. Doing this conversion is optional.
-// #[cfg(any(test, doctest))]
-impl From<Error<ser::Error>> for Error<de::Error> {
-    fn from(value: Error<ser::Error>) -> Self {
-        match value {
-            Error::BadIndex => Self::BadIndex,
-            Error::PathAbsent => Self::PathAbsent,
-            Error::PathNotFound => Self::PathNotFound,
-            Error::PathTooLong => Self::PathTooLong,
-            Error::PathTooShort => Self::PathTooShort,
-            Error::PostDeserialization(_) => Error::PostDeserialization(de::Error::CustomError),
-            Error::SerDe(_) => Self::SerDe(de::Error::CustomError),
-        }
+        Ok(buf.position() as _)
     }
 }
diff --git a/src/json_core.rs b/src/json_core.rs
new file mode 100644
index 00000000..9fff12cc
--- /dev/null
+++ b/src/json_core.rs
@@ -0,0 +1,46 @@
+use crate::{Error, Miniconf, SerDe};
+use serde_json_core::{de, ser};
+
+/// Marker struct for the "JSON and `/`" [SerDe] specification.
+///
+/// Access items with `'/'` as path separator and JSON (from `serde-json-core`)
+/// as serialization/deserialization payload format.
+pub struct JsonCoreSlash;
+
+impl<T> SerDe<JsonCoreSlash> for T
+where
+    T: Miniconf,
+{
+    const SEPARATOR: char = '/';
+    type DeError = de::Error;
+    type SerError = ser::Error;
+
+    fn set(&mut self, path: &str, data: &[u8]) -> Result<usize, Error<Self::DeError>> {
+        let mut de = de::Deserializer::new(data);
+        self.set_path(&mut path.split(Self::SEPARATOR).skip(1), &mut de)?;
+        de.end().map_err(Error::PostDeserialization)
+    }
+
+    fn get(&self, path: &str, data: &mut [u8]) -> Result<usize, Error<Self::SerError>> {
+        let mut ser = ser::Serializer::new(data);
+        self.get_path(&mut path.split(Self::SEPARATOR).skip(1), &mut ser)?;
+        Ok(ser.end())
+    }
+}
+
+// These allow unifying serde error information to make writing examples
+// and tests easier. Doing this conversion is optional.
+// #[cfg(any(test, doctest))]
+impl From<Error<ser::Error>> for Error<de::Error> {
+    fn from(value: Error<ser::Error>) -> Self {
+        match value {
+            Error::BadIndex => Self::BadIndex,
+            Error::PathAbsent => Self::PathAbsent,
+            Error::PathNotFound => Self::PathNotFound,
+            Error::PathTooLong => Self::PathTooLong,
+            Error::PathTooShort => Self::PathTooShort,
+            Error::PostDeserialization(_) => Error::PostDeserialization(de::Error::CustomError),
+            Error::SerDe(_) => Self::SerDe(de::Error::CustomError),
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 6ffc80e8..c981a0d1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,5 @@
-#![cfg_attr(not(any(test, doctest)), no_std)]
-#![cfg_attr(feature = "json", doc = include_str!("../README.md"))]
+#![cfg_attr(not(any(test, doctest, feature = "std")), no_std)]
+#![cfg_attr(feature = "json-core", doc = include_str!("../README.md"))]
 
 use core::fmt::Write;
 
@@ -11,16 +11,21 @@ pub use iter::*;
 mod option;
 pub use option::*;
 
+#[cfg(feature = "json-core")]
+mod json_core;
+#[cfg(feature = "json-core")]
+pub use json_core::*;
+
 #[cfg(feature = "json")]
 mod json;
 #[cfg(feature = "json")]
 pub use json::*;
 
-#[cfg(feature = "mqtt")]
+#[cfg(feature = "mqtt-client")]
 pub use minimq; // re-export
-#[cfg(feature = "mqtt")]
+#[cfg(feature = "mqtt-client")]
 mod mqtt_client;
-#[cfg(feature = "mqtt")]
+#[cfg(feature = "mqtt-client")]
 pub use mqtt_client::*;
 
 pub use serde; // re-export
diff --git a/src/mqtt_client/mod.rs b/src/mqtt_client/mod.rs
index a3304c69..4fcd2f77 100644
--- a/src/mqtt_client/mod.rs
+++ b/src/mqtt_client/mod.rs
@@ -1,12 +1,12 @@
 use crate::{JsonCoreSlash, Miniconf, SerDe};
 use core::fmt::Write;
+use heapless::{String, Vec};
 use minimq::{
     embedded_nal::{IpAddr, TcpClientStack},
     embedded_time,
     types::{SubscriptionOptions, TopicFilter},
     Publication, QoS, Retain,
 };
-use serde_json_core::heapless::{String, Vec};
 
 // The maximum topic length of any settings path.
 const MAX_TOPIC_LENGTH: usize = 128;
diff --git a/tests/arrays.rs b/tests/arrays.rs
index db0d4f55..9609b97a 100644
--- a/tests/arrays.rs
+++ b/tests/arrays.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Array, Error, Miniconf, SerDe};
 use serde::Deserialize;
diff --git a/tests/enums.rs b/tests/enums.rs
index 2de9842a..61670b46 100644
--- a/tests/enums.rs
+++ b/tests/enums.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Miniconf, SerDe};
 use serde::{Deserialize, Serialize};
diff --git a/tests/generics.rs b/tests/generics.rs
index 61a4188c..2b2d6a07 100644
--- a/tests/generics.rs
+++ b/tests/generics.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Miniconf, SerDe};
 use serde::{Deserialize, Serialize};
diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 1fbf9f2b..bcdf8765 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -1,4 +1,4 @@
-#![cfg(features = "mqtt")]
+#![cfg(features = "mqtt-client")]
 
 use machine::*;
 use miniconf::{
diff --git a/tests/iter.rs b/tests/iter.rs
index 8ef76af7..7b771f60 100644
--- a/tests/iter.rs
+++ b/tests/iter.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Miniconf, SerDe};
 
diff --git a/tests/json.rs b/tests/json.rs
new file mode 100644
index 00000000..65fddef1
--- /dev/null
+++ b/tests/json.rs
@@ -0,0 +1,20 @@
+#![cfg(feature = "json")]
+
+use miniconf::{Miniconf, SerDe};
+
+#[test]
+fn struct_with_string() {
+    #[derive(Miniconf, Default)]
+    struct Settings {
+        string: String,
+    }
+
+    let mut s = Settings::default();
+
+    let mut buf = [0u8; 256];
+    let len = s.get("/string", &mut buf).unwrap();
+    assert_eq!(&buf[..len], b"\"\"");
+
+    s.set("/string", br#""test""#).unwrap();
+    assert_eq!(s.string, "test");
+}
diff --git a/tests/option.rs b/tests/option.rs
index 3dbda8d2..7332b15d 100644
--- a/tests/option.rs
+++ b/tests/option.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Error, Miniconf, SerDe};
 
diff --git a/tests/republish.rs b/tests/republish.rs
index 5d54340d..ca5f9297 100644
--- a/tests/republish.rs
+++ b/tests/republish.rs
@@ -1,4 +1,4 @@
-#![cfg(features = "mqtt")]
+#![cfg(features = "mqtt-client")]
 
 use miniconf::{
     minimq::{self, types::TopicFilter},
diff --git a/tests/structs.rs b/tests/structs.rs
index 5601866d..5c3fe7ea 100644
--- a/tests/structs.rs
+++ b/tests/structs.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "json")]
+#![cfg(feature = "json-core")]
 
 use miniconf::{Miniconf, SerDe};
 use serde::{Deserialize, Serialize};
@@ -78,23 +78,6 @@ fn recursive_struct() {
     assert_eq!(metadata.count, 3);
 }
 
-#[test]
-fn struct_with_string() {
-    #[derive(Miniconf, Default)]
-    struct Settings {
-        string: heapless::String<10>,
-    }
-
-    let mut s = Settings::default();
-
-    let mut buf = [0u8; 256];
-    let len = s.get("/string", &mut buf).unwrap();
-    assert_eq!(&buf[..len], b"\"\"");
-
-    s.set("/string", br#""test""#).unwrap();
-    assert_eq!(s.string, "test");
-}
-
 #[test]
 fn empty_struct() {
     #[derive(Miniconf, Default)]
diff --git a/tests/validation_failure.rs b/tests/validation_failure.rs
index 8e32f129..05ebc1fa 100644
--- a/tests/validation_failure.rs
+++ b/tests/validation_failure.rs
@@ -1,4 +1,4 @@
-#![cfg(features = "mqtt")]
+#![cfg(features = "mqtt-client")]
 
 use miniconf::{minimq, Miniconf};
 use serde::Deserialize;