diff --git a/Cargo.toml b/Cargo.toml
index cabc2e5a983..2911fd312c4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -82,7 +82,7 @@ pin-project = "0.4.17"
 smallvec = "1.0"
 wasm-timer = "0.2.4"
 
-[target.'cfg(not(any(target_os = "emscripten", target_os = "unknown")))'.dependencies]
+[target.'cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))'.dependencies]
 libp2p-deflate = { version = "0.19.2", path = "protocols/deflate", optional = true }
 libp2p-dns = { version = "0.19.0", path = "transports/dns", optional = true }
 libp2p-mdns = { version = "0.19.2", path = "protocols/mdns", optional = true }
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 7253dd3da11..05311f95879 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -35,7 +35,7 @@ unsigned-varint = "0.4"
 void = "1"
 zeroize = "1"
 
-[target.'cfg(not(any(target_os = "emscripten", target_os = "unknown")))'.dependencies]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ring = { version = "0.16.9", features = ["alloc", "std"], default-features = false }
 
 [dev-dependencies]
diff --git a/core/src/identity.rs b/core/src/identity.rs
index da5ecb5657d..4b65f1a5dbd 100644
--- a/core/src/identity.rs
+++ b/core/src/identity.rs
@@ -21,7 +21,7 @@
 //! A node's network identity keys.
 
 pub mod ed25519;
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(target_arch = "wasm32"))]
 pub mod rsa;
 #[cfg(feature = "secp256k1")]
 pub mod secp256k1;
@@ -52,7 +52,7 @@ use crate::{PeerId, keys_proto};
 pub enum Keypair {
     /// An Ed25519 keypair.
     Ed25519(ed25519::Keypair),
-    #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     /// An RSA keypair.
     Rsa(rsa::Keypair),
     /// A Secp256k1 keypair.
@@ -76,7 +76,7 @@ impl Keypair {
     /// format (i.e. unencrypted) as defined in [RFC5208].
     ///
     /// [RFC5208]: https://tools.ietf.org/html/rfc5208#section-5
-    #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     pub fn rsa_from_pkcs8(pkcs8_der: &mut [u8]) -> Result<Keypair, DecodingError> {
         rsa::Keypair::from_pkcs8(pkcs8_der).map(Keypair::Rsa)
     }
@@ -97,7 +97,7 @@ impl Keypair {
         use Keypair::*;
         match self {
             Ed25519(ref pair) => Ok(pair.sign(msg)),
-            #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+            #[cfg(not(target_arch = "wasm32"))]
             Rsa(ref pair) => pair.sign(msg),
             #[cfg(feature = "secp256k1")]
             Secp256k1(ref pair) => pair.secret().sign(msg)
@@ -109,7 +109,7 @@ impl Keypair {
         use Keypair::*;
         match self {
             Ed25519(pair) => PublicKey::Ed25519(pair.public()),
-            #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+            #[cfg(not(target_arch = "wasm32"))]
             Rsa(pair) => PublicKey::Rsa(pair.public()),
             #[cfg(feature = "secp256k1")]
             Secp256k1(pair) => PublicKey::Secp256k1(pair.public().clone()),
@@ -122,7 +122,7 @@ impl Keypair {
 pub enum PublicKey {
     /// A public Ed25519 key.
     Ed25519(ed25519::PublicKey),
-    #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     /// A public RSA key.
     Rsa(rsa::PublicKey),
     #[cfg(feature = "secp256k1")]
@@ -139,7 +139,7 @@ impl PublicKey {
         use PublicKey::*;
         match self {
             Ed25519(pk) => pk.verify(msg, sig),
-            #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+            #[cfg(not(target_arch = "wasm32"))]
             Rsa(pk) => pk.verify(msg, sig),
             #[cfg(feature = "secp256k1")]
             Secp256k1(pk) => pk.verify(msg, sig)
@@ -157,7 +157,7 @@ impl PublicKey {
                     r#type: keys_proto::KeyType::Ed25519 as i32,
                     data: key.encode().to_vec()
                 },
-            #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+            #[cfg(not(target_arch = "wasm32"))]
             PublicKey::Rsa(key) =>
                 keys_proto::PublicKey {
                     r#type: keys_proto::KeyType::Rsa as i32,
@@ -192,11 +192,11 @@ impl PublicKey {
             keys_proto::KeyType::Ed25519 => {
                 ed25519::PublicKey::decode(&pubkey.data).map(PublicKey::Ed25519)
             },
-            #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+            #[cfg(not(target_arch = "wasm32"))]
             keys_proto::KeyType::Rsa => {
                 rsa::PublicKey::decode_x509(&pubkey.data).map(PublicKey::Rsa)
             }
-            #[cfg(any(target_os = "emscripten", target_os = "unknown"))]
+            #[cfg(target_arch = "wasm32")]
             keys_proto::KeyType::Rsa => {
                 log::debug!("support for RSA was disabled at compile-time");
                 Err(DecodingError::new("Unsupported"))
diff --git a/protocols/noise/Cargo.toml b/protocols/noise/Cargo.toml
index ec3b60c596b..4936b7933e2 100644
--- a/protocols/noise/Cargo.toml
+++ b/protocols/noise/Cargo.toml
@@ -20,10 +20,10 @@ static_assertions = "1"
 x25519-dalek = "0.6.0"
 zeroize = "1"
 
-[target.'cfg(not(target_os = "unknown"))'.dependencies]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 snow = { version = "0.7.0", features = ["ring-resolver"], default-features = false }
 
-[target.'cfg(target_os = "unknown")'.dependencies]
+[target.'cfg(target_arch = "wasm32")'.dependencies]
 snow = { version = "0.7.0", features = ["default-resolver"], default-features = false }
 
 [dev-dependencies]
diff --git a/protocols/noise/src/protocol.rs b/protocols/noise/src/protocol.rs
index 5844dbc8212..7c61274acb5 100644
--- a/protocols/noise/src/protocol.rs
+++ b/protocols/noise/src/protocol.rs
@@ -229,22 +229,22 @@ impl snow::resolvers::CryptoResolver for Resolver {
     }
 
     fn resolve_hash(&self, choice: &snow::params::HashChoice) -> Option<Box<dyn snow::types::Hash>> {
-        #[cfg(target_os = "unknown")]
+        #[cfg(target_arch = "wasm32")]
         {
             snow::resolvers::DefaultResolver.resolve_hash(choice)
         }
-        #[cfg(not(target_os = "unknown"))]
+        #[cfg(not(target_arch = "wasm32"))]
         {
             snow::resolvers::RingResolver.resolve_hash(choice)
         }
     }
 
     fn resolve_cipher(&self, choice: &snow::params::CipherChoice) -> Option<Box<dyn snow::types::Cipher>> {
-        #[cfg(target_os = "unknown")]
+        #[cfg(target_arch = "wasm32")]
         {
             snow::resolvers::DefaultResolver.resolve_cipher(choice)
         }
-        #[cfg(not(target_os = "unknown"))]
+        #[cfg(not(target_arch = "wasm32"))]
         {
             snow::resolvers::RingResolver.resolve_cipher(choice)
         }
diff --git a/protocols/secio/src/algo_support.rs b/protocols/secio/src/algo_support.rs
index 21114cde919..5e6d5e461f5 100644
--- a/protocols/secio/src/algo_support.rs
+++ b/protocols/secio/src/algo_support.rs
@@ -24,7 +24,7 @@
 //! helps you with.
 
 use crate::error::SecioError;
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 use ring::digest;
 use std::cmp::Ordering;
 use crate::stream_cipher::Cipher;
@@ -204,7 +204,7 @@ pub fn select_digest(r: Ordering, ours: &str, theirs: &str) -> Result<Digest, Se
     Err(SecioError::NoSupportIntersection)
 }
 
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 impl Into<&'static digest::Algorithm> for Digest {
     #[inline]
     fn into(self) -> &'static digest::Algorithm {
diff --git a/protocols/secio/src/exchange.rs b/protocols/secio/src/exchange.rs
index c1a9bad6590..1ae4120b7fc 100644
--- a/protocols/secio/src/exchange.rs
+++ b/protocols/secio/src/exchange.rs
@@ -24,10 +24,10 @@ use futures::prelude::*;
 use crate::SecioError;
 
 #[path = "exchange/impl_ring.rs"]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 mod platform;
 #[path = "exchange/impl_webcrypto.rs"]
-#[cfg(any(target_os = "emscripten", target_os = "unknown"))]
+#[cfg(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown"))]
 mod platform;
 
 /// Possible key agreement algorithms.
diff --git a/protocols/secio/src/handshake.rs b/protocols/secio/src/handshake.rs
index faffccc9d36..e436a777cc1 100644
--- a/protocols/secio/src/handshake.rs
+++ b/protocols/secio/src/handshake.rs
@@ -371,7 +371,7 @@ mod tests {
     use futures::{prelude::*, channel::oneshot};
 
     #[test]
-    #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+    #[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
     fn handshake_with_self_succeeds_rsa() {
         let key1 = {
             let mut private = include_bytes!("../tests/test-rsa-private-key.pk8").to_vec();
diff --git a/src/lib.rs b/src/lib.rs
index 1dab7142765..eb68a331deb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -85,7 +85,7 @@
 //! Example ([`secio`] + [`yamux`] Protocol Upgrade):
 //!
 //! ```rust
-//! # #[cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), feature = "tcp-async-std", feature = "secio", feature = "yamux"))] {
+//! # #[cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), feature = "tcp-async-std", feature = "secio", feature = "yamux"))] {
 //! use libp2p::{Transport, core::upgrade, tcp::TcpConfig, secio::SecioConfig, identity::Keypair, yamux};
 //! let tcp = TcpConfig::new();
 //! let secio = SecioConfig::new(Keypair::generate_ed25519());
@@ -166,12 +166,12 @@ pub use multihash;
 pub use libp2p_core as core;
 #[cfg(feature = "deflate")]
 #[cfg_attr(docsrs, doc(cfg(feature = "deflate")))]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_deflate as deflate;
 #[cfg(feature = "dns")]
 #[cfg_attr(docsrs, doc(cfg(feature = "dns")))]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_dns as dns;
 #[cfg(feature = "identify")]
@@ -196,7 +196,7 @@ pub use libp2p_gossipsub as gossipsub;
 pub use libp2p_mplex as mplex;
 #[cfg(feature = "mdns")]
 #[cfg_attr(docsrs, doc(cfg(feature = "mdns")))]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_mdns as mdns;
 #[cfg(feature = "noise")]
@@ -219,7 +219,7 @@ pub use libp2p_secio as secio;
 pub use libp2p_swarm as swarm;
 #[cfg(any(feature = "tcp-async-std", feature = "tcp-tokio"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "tcp-async-std", feature = "tcp-tokio"))))]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_tcp as tcp;
 #[cfg(feature = "uds")]
@@ -232,7 +232,7 @@ pub use libp2p_uds as uds;
 pub use libp2p_wasm_ext as wasm_ext;
 #[cfg(feature = "websocket")]
 #[cfg_attr(docsrs, doc(cfg(feature = "websocket")))]
-#[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_websocket as websocket;
 #[cfg(feature = "yamux")]
@@ -266,8 +266,8 @@ pub use self::transport_ext::TransportExt;
 ///
 /// > **Note**: This `Transport` is not suitable for production usage, as its implementation
 /// >           reserves the right to support additional protocols or remove deprecated protocols.
-#[cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))]
-#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))))]
+#[cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))]
+#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))))]
 pub fn build_development_transport(keypair: identity::Keypair)
     -> std::io::Result<impl Transport<Output = (PeerId, impl core::muxing::StreamMuxer<OutboundSubstream = impl Send, Substream = impl Send, Error = impl Into<std::io::Error>> + Send + Sync), Error = impl std::error::Error + Send, Listener = impl Send, Dial = impl Send, ListenerUpgrade = impl Send> + Clone>
 {
@@ -280,8 +280,8 @@ pub fn build_development_transport(keypair: identity::Keypair)
 /// and mplex or yamux as the multiplexing layer.
 ///
 /// > **Note**: If you ever need to express the type of this `Transport`.
-#[cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))]
-#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))))]
+#[cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))]
+#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux"))))]
 pub fn build_tcp_ws_secio_mplex_yamux(keypair: identity::Keypair)
     -> std::io::Result<impl Transport<Output = (PeerId, impl core::muxing::StreamMuxer<OutboundSubstream = impl Send, Substream = impl Send, Error = impl Into<std::io::Error>> + Send + Sync), Error = impl std::error::Error + Send, Listener = impl Send, Dial = impl Send, ListenerUpgrade = impl Send> + Clone>
 {
@@ -309,8 +309,8 @@ pub fn build_tcp_ws_secio_mplex_yamux(keypair: identity::Keypair)
 /// and mplex or yamux as the multiplexing layer.
 ///
 /// > **Note**: If you ever need to express the type of this `Transport`.
-#[cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux", feature = "pnet"))]
-#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux", feature = "pnet"))))]
+#[cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux", feature = "pnet"))]
+#[cfg_attr(docsrs, doc(cfg(all(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")), any(feature = "tcp-async-std", feature = "tcp-tokio"), feature = "websocket", feature = "secio", feature = "mplex", feature = "yamux", feature = "pnet"))))]
 pub fn build_tcp_ws_pnet_secio_mplex_yamux(keypair: identity::Keypair, psk: PreSharedKey)
     -> std::io::Result<impl Transport<Output = (PeerId, impl core::muxing::StreamMuxer<OutboundSubstream = impl Send, Substream = impl Send, Error = impl Into<std::io::Error>> + Send + Sync), Error = impl std::error::Error + Send, Listener = impl Send, Dial = impl Send, ListenerUpgrade = impl Send> + Clone>
 {
diff --git a/transports/uds/Cargo.toml b/transports/uds/Cargo.toml
index ae8f2492367..f72fe8b8ffc 100644
--- a/transports/uds/Cargo.toml
+++ b/transports/uds/Cargo.toml
@@ -9,14 +9,14 @@ repository = "https://github.com/libp2p/rust-libp2p"
 keywords = ["peer-to-peer", "libp2p", "networking"]
 categories = ["network-programming", "asynchronous"]
 
-[target.'cfg(all(unix, not(any(target_os = "emscripten", target_os = "unknown"))))'.dependencies]
+[target.'cfg(all(unix, not(target_os = "emscripten")))'.dependencies]
 async-std = { version = "1.6.2", optional = true }
 libp2p-core = { version = "0.19.2", path = "../../core" }
 log = "0.4.1"
 futures = "0.3.1"
 tokio = { version = "0.2", default-features = false, features = ["uds"], optional = true }
 
-[target.'cfg(all(unix, not(any(target_os = "emscripten", target_os = "unknown"))))'.dev-dependencies]
+[target.'cfg(all(unix, not(target_os = "emscripten")))'.dev-dependencies]
 tempfile = "3.0"
 
 [features]
diff --git a/transports/uds/src/lib.rs b/transports/uds/src/lib.rs
index 44bad943c2a..05efae630bb 100644
--- a/transports/uds/src/lib.rs
+++ b/transports/uds/src/lib.rs
@@ -31,8 +31,8 @@
 //! The `UdsConfig` structs implements the `Transport` trait of the `core` library. See the
 //! documentation of `core` and of libp2p in general to learn how to use the `Transport` trait.
 
-#![cfg(all(unix, not(any(target_os = "emscripten", target_os = "unknown"))))]
-#![cfg_attr(docsrs, doc(cfg(all(unix, not(any(target_os = "emscripten", target_os = "unknown"))))))]
+#![cfg(all(unix, not(target_os = "emscripten")))]
+#![cfg_attr(docsrs, doc(cfg(all(unix, not(target_os = "emscripten")))))]
 
 use futures::{prelude::*, future::{BoxFuture, Ready}};
 use futures::stream::BoxStream;