algorand
diff --git a/‎agreement/gossip/networkFull_test.go
+1-2 b/‎agreement/gossip/networkFull_test.go
+1-2
diff --git a/‎config/localTemplate.go
+11-4 b/‎config/localTemplate.go
+11-4
diff --git a/‎config/local_defaults.go
+2 b/‎config/local_defaults.go
+2
diff --git a/‎daemon/algod/api/algod.oas2.json
+87-13 b/‎daemon/algod/api/algod.oas2.json
+87-13
@@ -38,7 +38,7 @@ func TestMain(m *testing.M) {
 
 	logging.Base().SetLevel(logging.Debug)
 	// increase limit on max allowed number of sockets
-	err := util.RaiseRlimit(500)
+	err := util.SetFdSoftLimit(500)
 	if err != nil {
 		os.Exit(1)
 	}
@@ -50,7 +50,6 @@ func spinNetwork(t *testing.T, nodesCount int) ([]*networkImpl, []*messageCounte
 	cfg := config.GetDefaultLocal()
 	cfg.GossipFanout = nodesCount - 1
 	cfg.NetAddress = "127.0.0.1:0"
-	cfg.IncomingConnectionsLimit = -1
 	cfg.IncomingMessageFilterBucketCount = 5
 	cfg.IncomingMessageFilterBucketSize = 32
 	cfg.OutgoingMessageFilterBucketCount = 3
 
@@ -74,7 +74,7 @@ type Local struct {
 	CadaverSizeTarget uint64 `version[0]:"1073741824"`
 
 	// IncomingConnectionsLimit specifies the max number of long-lived incoming
-	// connections.  0 means no connections allowed.  -1 is unbounded.
+	// connections. 0 means no connections allowed. Must be non-negative.
 	// Estimating 5MB per incoming connection, 5MB*800 = 4GB
 	IncomingConnectionsLimit int `version[0]:"-1" version[1]:"10000" version[17]:"800"`
 
@@ -99,9 +99,9 @@ type Local struct {
 	PriorityPeers map[string]bool `version[4]:""`
 
 	// To make sure the algod process does not run out of FDs, algod ensures
-	// that RLIMIT_NOFILE exceeds the max number of incoming connections (i.e.,
-	// IncomingConnectionsLimit) by at least ReservedFDs.  ReservedFDs are meant
-	// to leave room for short-lived FDs like DNS queries, SQLite files, etc.
+	// that RLIMIT_NOFILE >= IncomingConnectionsLimit + RestConnectionsHardLimit +
+	// ReservedFDs. ReservedFDs are meant to leave room for short-lived FDs like
+	// DNS queries, SQLite files, etc. This parameter shouldn't be changed.
 	ReservedFDs uint64 `version[2]:"256"`
 
 	// local server
@@ -423,6 +423,13 @@ type Local struct {
 
 	// ProposalAssemblyTime is the max amount of time to spend on generating a proposal block.
 	ProposalAssemblyTime time.Duration `version[19]:"250000000"`
+
+	// When the number of http connections to the REST layer exceeds the soft limit,
+	// we start returning http code 429 Too Many Requests.
+	RestConnectionsSoftLimit uint64 `version[20]:"1024"`
+	// The http server does not accept new connections as long we have this many
+	// (hard limit) connections already.
+	RestConnectionsHardLimit uint64 `version[20]:"2048"`
 }
 
 // DNSBootstrapArray returns an array of one or more DNS Bootstrap identifiers
 
@@ -99,6 +99,8 @@ var defaultLocal = Local{
 	PublicAddress:                              "",
 	ReconnectTime:                              60000000000,
 	ReservedFDs:                                256,
+	RestConnectionsHardLimit:                   2048,
+	RestConnectionsSoftLimit:                   1024,
 	RestReadTimeoutSeconds:                     15,
 	RestWriteTimeoutSeconds:                    120,
 	RunHosted:                                  false,
 
@@ -494,7 +494,7 @@
             }
           },
           "404": {
-            "description": "Application Not Found",
+            "description": "Participation Key Not Found",
             "schema": {
               "$ref": "#/definitions/ErrorResponse"
             }
@@ -553,6 +553,12 @@
               "$ref": "#/definitions/ErrorResponse"
             }
           },
+          "404": {
+            "description": "Participation Key Not Found",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
           "500": {
             "description": "Internal Error",
             "schema": {
@@ -576,14 +582,14 @@
         "tags": [
           "private"
         ],
-        "description": "Delete a given participation key by id",
+        "description": "Delete a given participation key by ID",
         "produces": [
           "application/json"
         ],
         "schemes": [
           "http"
         ],
-        "summary": "Delete a given participation key by id",
+        "summary": "Delete a given participation key by ID",
         "operationId": "DeleteParticipationKeyByID",
         "responses": {
           "200": {
@@ -601,6 +607,12 @@
               "$ref": "#/definitions/ErrorResponse"
             }
           },
+          "404": {
+            "description": "Participation Key Not Found",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
           "500": {
             "description": "Internal Error",
             "schema": {
@@ -616,14 +628,14 @@
         "tags": [
           "private"
         ],
-        "description": "Given a participation id, return information about that participation key",
+        "description": "Given a participation ID, return information about that participation key",
         "produces": [
           "application/json"
         ],
         "schemes": [
           "http"
         ],
-        "summary": "Get participation key info by id",
+        "summary": "Get participation key info given a participation ID",
         "operationId": "GetParticipationKeyByID",
         "responses": {
           "200": {
@@ -643,7 +655,69 @@
             }
           },
           "404": {
-            "description": "Application Not Found",
+            "description": "Participation Key Not Found",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
+          "500": {
+            "description": "Internal Error",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
+          "default": {
+            "description": "Unknown Error"
+          }
+        }
+      },
+      "post": {
+        "tags": [
+          "private"
+        ],
+        "description": "Given a participation ID, append state proof keys to a particular set of participation keys",
+        "consumes": [
+          "application/msgpack"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "parameters": [
+          {
+            "description": "The state proof keys to add to an existing participation ID",
+            "name": "keymap",
+            "in": "body",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "format": "binary"
+            }
+          }
+        ],
+        "schemes": [
+          "http"
+        ],
+        "summary": "Append state proof keys to a participation key",
+        "operationId": "AppendKeys",
+        "responses": {
+          "200": {
+            "description": "OK",
+            "$ref": "#/responses/ParticipationKeyResponse"
+          },
+          "400": {
+            "description": "Bad Request",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
+          "401": {
+            "description": "Invalid API Token",
+            "schema": {
+              "$ref": "#/definitions/ErrorResponse"
+            }
+          },
+          "404": {
+            "description": "Participation Key Not Found",
             "schema": {
               "$ref": "#/definitions/ErrorResponse"
             }
@@ -934,7 +1008,7 @@
     },
     "/v2/transactions/pending/{txid}": {
       "get": {
-        "description": "Given a transaction id of a recently submitted transaction, it returns information about it.  There are several cases when this might succeed:\n- transaction committed (committed round \u003e 0)\n- transaction still in the pool (committed round = 0, pool error = \"\")\n- transaction removed from pool due to error (committed round = 0, pool error != \"\")\nOr the transaction may have happened sufficiently long ago that the node no longer remembers it, and this will return an error.\n",
+        "description": "Given a transaction ID of a recently submitted transaction, it returns information about it.  There are several cases when this might succeed:\n- transaction committed (committed round \u003e 0)\n- transaction still in the pool (committed round = 0, pool error = \"\")\n- transaction removed from pool due to error (committed round = 0, pool error != \"\")\nOr the transaction may have happened sufficiently long ago that the node no longer remembers it, and this will return an error.\n",
         "produces": [
           "application/json",
           "application/msgpack"
@@ -948,7 +1022,7 @@
           {
             "pattern": "[A-Z0-9]+",
             "type": "string",
-            "description": "A transaction id",
+            "description": "A transaction ID",
             "name": "txid",
             "in": "path",
             "required": true
@@ -959,7 +1033,7 @@
         ],
         "responses": {
           "200": {
-            "description": "Given a transaction id of a recently submitted transaction, it returns information about it.  There are several cases when this might succeed:\n- transaction committed (committed round \u003e 0)\n- transaction still in the pool (committed round = 0, pool error = \"\")\n- transaction removed from pool due to error (committed round = 0, pool error != \"\")\n\nOr the transaction may have happened sufficiently long ago that the node no longer remembers it, and this will return an error.",
+            "description": "Given a transaction ID of a recently submitted transaction, it returns information about it.  There are several cases when this might succeed:\n- transaction committed (committed round \u003e 0)\n- transaction still in the pool (committed round = 0, pool error = \"\")\n- transaction removed from pool due to error (committed round = 0, pool error != \"\")\n\nOr the transaction may have happened sufficiently long ago that the node no longer remembers it, and this will return an error.",
             "schema": {
               "$ref": "#/definitions/PendingTransactionResponse"
             }
@@ -998,7 +1072,7 @@
     },
     "/v2/applications/{application-id}": {
       "get": {
-        "description": "Given a application id, it returns application information including creator, approval and clear programs, global and local schemas, and global state.",
+        "description": "Given a application ID, it returns application information including creator, approval and clear programs, global and local schemas, and global state.",
         "produces": [
           "application/json"
         ],
@@ -1061,7 +1135,7 @@
     },
     "/v2/assets/{asset-id}": {
       "get": {
-        "description": "Given a asset id, it returns asset information including creator, name, total supply and special addresses.",
+        "description": "Given a asset ID, it returns asset information including creator, name, total supply and special addresses.",
         "produces": [
           "application/json"
         ],
@@ -2576,7 +2650,7 @@
       }
     },
     "ParticipationKeyResponse": {
-      "description": "A detailed description of a participation id",
+      "description": "A detailed description of a participation ID",
       "schema": {
         "$ref": "#/definitions/ParticipationKey"
       }
@@ -2593,7 +2667,7 @@
         ],
         "properties": {
           "partId": {
-            "description": "encoding of the participation id.",
+            "description": "encoding of the participation ID.",
             "type": "string"
           }
         }