diff --git a/docs/API.md b/docs/API.md
index d4d85878..bfc9bc47 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -55,6 +55,17 @@ The response is a JSON object with fields:
 * `success`: whether the credentials provided were valid
 * `accountName`: canonical, case-unfolded version of the account name
 
+`/v1/defcon`
+------------
+
+This endpoint can be used to view or modify the DEFCON level (see `/helpop defcon` for details). If the request is empty, the existing level is returned. To change the level, send a JSON object with fields:
+
+* `defcon`: integer, desired new value of the DEFCON setting (between 5 for normal operation and 1 for the most restrictive)
+
+The response is a JSON object with fields:
+
+* `defcon`: integer, current (or new) value of the DEFCON setting
+
 `/v1/list`
 ----------
 
@@ -71,7 +82,7 @@ Each channel object has fields:
 * `hasKey`: boolean, whether the channel has a key set with the `+k` mode
 * `inviteOnly`: boolean, whether the channel has the `+i` invite-only mode set
 * `secret`: boolean, whether the channel has the `+s` secret mode set (and would be hidden from an unprivileged `LIST` command)
-* `userCount`: int, number of users in the channel
+* `userCount`: integer, number of users in the channel
 * `topic`: string, channel topic
 * `topicSetAt`: string, time the topic was last updated (in ISO8601 format)
 * `createdAt`: string, time the channel was created (in ISO8601 format)
diff --git a/irc/api.go b/irc/api.go
index baf489cc..2e00c054 100644
--- a/irc/api.go
+++ b/irc/api.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/ergochat/ergo/irc/modes"
+	"github.com/ergochat/ergo/irc/sno"
 	"github.com/ergochat/ergo/irc/utils"
 )
 
@@ -22,6 +23,7 @@ func newAPIHandler(server *Server) http.Handler {
 	api.mux.HandleFunc("POST /v1/rehash", api.handleRehash)
 	api.mux.HandleFunc("POST /v1/status", api.handleStatus)
 	api.mux.HandleFunc("POST /v1/list", api.handleList)
+	api.mux.HandleFunc("POST /v1/defcon", api.handleDefcon)
 
 	// use Ergo as a source of truth for authentication in other services:
 	api.mux.HandleFunc("POST /v1/check_auth", api.handleCheckAuth)
@@ -119,6 +121,34 @@ func (a *ergoAPI) handleRehash(w http.ResponseWriter, r *http.Request) {
 	a.writeJSONResponse(response, w, r)
 }
 
+type defconRequestResponse struct {
+	apiGenericResponse
+	Defcon int `json:"defcon"`
+}
+
+func (a *ergoAPI) handleDefcon(w http.ResponseWriter, r *http.Request) {
+	var changeRequested uint32
+	var request defconRequestResponse
+	// ignore errors or invalid values
+	if err := json.NewDecoder(r.Body).Decode(&request); err == nil {
+		if 1 <= request.Defcon && request.Defcon <= 5 {
+			changeRequested = uint32(request.Defcon)
+		}
+	}
+	if changeRequested != 0 {
+		a.server.SetDefcon(changeRequested)
+		message := fmt.Sprintf("API set DEFCON level to %d", changeRequested)
+		a.server.logger.Info("server", message)
+		a.server.snomasks.Send(sno.LocalAnnouncements, message)
+	}
+	a.writeJSONResponse(
+		defconRequestResponse{
+			apiGenericResponse: apiGenericResponse{Success: true},
+			Defcon:             int(a.server.Defcon()),
+		}, w, r,
+	)
+}
+
 type apiCheckAuthResponse struct {
 	apiGenericResponse
 	AccountName string `json:"accountName,omitempty"`
diff --git a/irc/handlers.go b/irc/handlers.go
index 5fc9d1da..b714f5db 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -942,7 +942,9 @@ func defconHandler(server *Server, client *Client, msg ircmsg.Message, rb *Respo
 		level, err := strconv.Atoi(msg.Params[0])
 		if err == nil && 1 <= level && level <= 5 {
 			server.SetDefcon(uint32(level))
-			server.snomasks.Send(sno.LocalAnnouncements, fmt.Sprintf("%s [%s] set DEFCON level to %d", client.Nick(), client.Oper().Name, level))
+			message := fmt.Sprintf("%s [%s] set DEFCON level to %d", client.Nick(), client.Oper().Name, level)
+			server.logger.Info("server", message)
+			server.snomasks.Send(sno.LocalAnnouncements, message)
 		} else {
 			rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), msg.Command, client.t("Invalid DEFCON parameter"))
 			return false