diff --git a/rfc/0004_ws2p_v1.md b/rfc/0004_ws2p_v1.md
index cf2a647657b1e3d7d5cdcd1c80c8a12eea3bc720..425b43705cf0175fdba91ca8f1c77c391afb2f81 100644
--- a/rfc/0004_ws2p_v1.md
+++ b/rfc/0004_ws2p_v1.md
@@ -34,10 +34,11 @@ WS2P is exclusively based on websocket technology.
 
 ### Endpoint format
 
-In the peer card : `WS2P uuid host port path`  
+In the peer card : `API uuid host port path`  
 Resolved in* : `ws://host:port/path`  
 *If the port is `443`, the `wss://` protocol will be used.
 
+api := Field indicating api type. The only two types are `WS2P` and `WS2PTOR`.
 uuid := Random sequence of 8 hexadecimal characters. (This uuid, coupled with the public key, makes it possible to identify a Duniter node in a unique way.)
 host := Domain name or ipv4 or ipv6 (it is not possible to declare both an ipv4 and an ipv6, for this it is necessary to use a domain name.)  
 port := Mandatory. Must be an integer. (_By convention, port 20900 is used for currency g1-test and port 20901 for currency g1._)  
@@ -243,16 +244,16 @@ Accepted since duniter-ts **v1.6.9**, relayed fully since duniter-ts **v1.6.15**
 _Nodes with versions lower than 1.6.15 bounce a degraded version of the head, only `message` and `sig` fields are relayed._
 
     {
-        message : "WS2P:HEAD:1:PUBKEY:BLOCKSTAMP:WS2PID:SOFTWARE:SOFT_VERSION:POW_PREFIX,
+        message : "API:HEAD:1:PUBKEY:BLOCKSTAMP:WS2PID:SOFTWARE:SOFT_VERSION:POW_PREFIX,
         sig : "TPh2A3NS8cHj8yrJk1Yeldx2H6bPEp46cFAGZXKfxJcNgXL2sWrlirhIOlp8pkUFSrwDawWY1zO1jlgUqMvlAg==",
-        messageV2: "WS2P:HEAD:2:PUBKEY:BLOCKSTAMP:WS2PID:SOFTWARE:SOFT_VERSION:POW_PREFIX:FREE_MEMBER_ROOM:FREE_MIRROR_ROOM",
+        messageV2: "API:HEAD:2:PUBKEY:BLOCKSTAMP:WS2PID:SOFTWARE:SOFT_VERSION:POW_PREFIX:FREE_MEMBER_ROOM:FREE_MIRROR_ROOM",
         sigV2: "ta1lRrWsjGcYHcLdS75JgEW5B8ByRetFVUVVpakKNJBirhRe8HcYUHEOM7xj/+gUQGGOit6Gm5Q/lsvfsngWAQ==",
         step: 0
     }
     
 #### message & messageV2 fields
 
-API = `WS2P`  
+API := field indicating the network layer type and giving some information about the Network configuration. (See section "API field" for details)
 MESSAGE_TYPE = `HEAD`  
 PUBKEY := public key of the issuer node of this head  
 BLOCKSTAMP = `blockNumber-Hash`  
@@ -263,6 +264,24 @@ POW_PREFIX := nonce prefix for proof of work (manually fixed by the user)
 FREE_MEMBER_ROOM := Number of incoming connection requests that can still be accepted from member nodes (FREE_MIROR_ROOM - Number of incoming connections established by non-priority mirror nodes).  
 FREE_MIROR_ROOM := An integer indicating the number of incoming connections that the node can still receive.
 
+##### API field
+
+general scheme : `WS2P[PrivateConf][PublicConf]`
+
+We have 4 types of WS2P Private:  
+OCA : clear all  
+OTM : tor mixed  
+OTA : tor all  
+OTS : tor strict
+
+And two types of WS2P Public :  
+IC clear endpoint  
+IT tor endpoint
+
+The WS2P Private conf is prefixed with an O and the ws2p public conf with an I, so the classic nodes will be of type `WS2POCAIC`.
+
+If WS2P Public is disabled, the [PublicConf] part is absent : `WS2POCA`
+
 #### sig & sigv2 fields
 
 sig: ed25519 signature of the message field in base64.