diff --git a/.github/workflows/juliaci.yml b/.github/workflows/juliaci.yml
index 888a57b3..79056ef5 100644
--- a/.github/workflows/juliaci.yml
+++ b/.github/workflows/juliaci.yml
@@ -17,3 +17,21 @@ jobs:
     permissions: write-all
     secrets:
       codecov_token: ${{ secrets.CODECOV_TOKEN }}
+
+  json-compat:
+    name: JSON ${{ matrix.json-version }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        json-version: ["0.21", "1.7"]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: "1"
+      - uses: julia-actions/cache@v2
+      - name: Install and verify JSON version
+        run: |
+          julia --project=. -e 'using Pkg; Pkg.add(PackageSpec(name="JSON", version="${{ matrix.json-version }}")); using JSON; @assert startswith(string(pkgversion(JSON)), "${{ matrix.json-version }}."); Pkg.status()'
+      - uses: julia-actions/julia-runtest@v1
diff --git a/Project.toml b/Project.toml
index 8d4c995b..8f0896a6 100644
--- a/Project.toml
+++ b/Project.toml
@@ -14,7 +14,7 @@ TestItemRunner = "f8b46487-2199-4994-9208-9a1283c18c0a"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
-JSON = "0.20, 0.21"
+JSON = "0.20, 0.21, 1"
 julia = "1"
 CancellationTokens = "2.0.2"
 
diff --git a/src/core.jl b/src/core.jl
index 86d66999..1cc8eca7 100644
--- a/src/core.jl
+++ b/src/core.jl
@@ -186,7 +186,7 @@ Used by the MCP (Model Context Protocol) stdio transport.
 """
 struct NewlineDelimitedFraming <: FramingMode end
 
-mutable struct JSONRPCEndpoint{IOIn<:IO,IOOut<:IO,S<:JSON.Serialization,F<:FramingMode}
+mutable struct JSONRPCEndpoint{IOIn<:IO,IOOut<:IO,S<:JSONSerialization,F<:FramingMode}
     pipe_in::IOIn
     pipe_out::IOOut
 
@@ -225,7 +225,7 @@ mutable struct JSONRPCEndpoint{IOIn<:IO,IOOut<:IO,S<:JSON.Serialization,F<:Frami
     close_started::Bool
 end
 
-JSONRPCEndpoint(pipe_in, pipe_out, serialization::JSON.Serialization=JSON.StandardSerialization(); framing::FramingMode=ContentLengthFraming()) =
+JSONRPCEndpoint(pipe_in, pipe_out, serialization::JSONSerialization=DefaultJSONSerialization(); framing::FramingMode=ContentLengthFraming()) =
     JSONRPCEndpoint(
         pipe_in,
         pipe_out,
@@ -496,7 +496,7 @@ function start(x::JSONRPCEndpoint)
                 end
 
                 message_dict = try
-                    JSON.parse(message)
+                    _parse_json(message)
                 catch parse_err
                     # Corrupted/truncated message (e.g. remote process crashed mid-write).
                     # Treat as broken pipe and exit the read loop.
@@ -616,7 +616,7 @@ function send_notification(x::JSONRPCEndpoint, method::AbstractString, @nospecia
 
     message = Dict("jsonrpc" => "2.0", "method" => method, "params" => params)
 
-    message_json = sprint(JSON.show_json, x.serialization, message)
+    message_json = _serialize_json(x.serialization, message)
 
     put!(x.out_msg_queue, message_json)
 
@@ -632,7 +632,7 @@ function send_request(x::JSONRPCEndpoint, method::AbstractString, @nospecialize(
     response_channel = Channel{Any}(1)
     x.outstanding_requests[id] = response_channel
 
-    message_json = sprint(JSON.show_json, x.serialization, message)
+    message_json = _serialize_json(x.serialization, message)
 
     put!(x.out_msg_queue, message_json)
 
@@ -834,7 +834,7 @@ function send_success_response(endpoint, original_request::Request, @nospecializ
 
     response = Dict("jsonrpc" => "2.0", "id" => original_request.id, "result" => result)
 
-    response_json = sprint(JSON.show_json, endpoint.serialization, response)
+    response_json = _serialize_json(endpoint.serialization, response)
 
     put!(endpoint.out_msg_queue, response_json)
 end
@@ -848,7 +848,7 @@ function send_error_response(endpoint, original_request::Request, @nospecialize(
 
     response = Dict("jsonrpc" => "2.0", "id" => original_request.id, "error" => Dict("code" => code, "message" => message, "data" => data))
 
-    response_json = sprint(JSON.show_json, endpoint.serialization, response)
+    response_json = _serialize_json(endpoint.serialization, response)
 
     put!(endpoint.out_msg_queue, response_json)
 end
diff --git a/src/interface_def.jl b/src/interface_def.jl
index 0e047f99..7ea7c81a 100644
--- a/src/interface_def.jl
+++ b/src/interface_def.jl
@@ -1,24 +1,14 @@
 abstract type Outbound end
 
-function JSON.Writer.CompositeTypeWrapper(t::Outbound)
-    fns = collect(fieldnames(typeof(t)))
-    dels = Int[]
-    for i = 1:length(fns)
-        f = fns[i]
-        if getfield(t, f) isa Missing
-            push!(dels, i)
-        end
-    end
-    deleteat!(fns, dels)
-    JSON.Writer.CompositeTypeWrapper(t, Tuple(fns))
-end
-
 function JSON.lower(a::Outbound)
-    if nfields(a) > 0
-        JSON.Writer.CompositeTypeWrapper(a)
-    else
-        nothing
+    nfields(a) == 0 && return nothing
+
+    fields = Dict{String,Any}()
+    for field in fieldnames(typeof(a))
+        value = getfield(a, field)
+        ismissing(value) || (fields[string(field)] = value)
     end
+    return fields
 end
 
 function field_allows_missing(field::Expr)
@@ -60,7 +50,7 @@ macro dict_readable(arg)
         end
         ) : nothing)
 
-        function $tname(dict::Dict)
+        function $tname(dict::AbstractDict)
         end
     end
 
diff --git a/src/jsoncompat.jl b/src/jsoncompat.jl
new file mode 100644
index 00000000..8bc3bb0b
--- /dev/null
+++ b/src/jsoncompat.jl
@@ -0,0 +1,17 @@
+@static if isdefined(JSON, :JSONStyle)
+    const JSONSerialization = JSON.JSONStyle
+    const DefaultJSONSerialization = JSON.JSONWriteStyle
+else
+    const JSONSerialization = JSON.Serialization
+    const DefaultJSONSerialization = JSON.StandardSerialization
+end
+
+function _serialize_json(serialization::JSONSerialization, value)
+    @static if isdefined(JSON, :JSONStyle)
+        return JSON.json(value; style=serialization)
+    else
+        return sprint(JSON.show_json, serialization, value)
+    end
+end
+
+_parse_json(value) = JSON.parse(value; dicttype=Dict{String,Any})
diff --git a/src/packagedef.jl b/src/packagedef.jl
index eab8e3da..8a1a7756 100644
--- a/src/packagedef.jl
+++ b/src/packagedef.jl
@@ -2,6 +2,7 @@ export JSONRPCEndpoint, TransportError, EndpointStatus, start, send_notification
 export FramingMode, ContentLengthFraming, NewlineDelimitedFraming
 
 include("pipenames.jl")
+include("jsoncompat.jl")
 include("core.jl")
 include("typed.jl")
 include("interface_def.jl")
@@ -9,7 +10,7 @@ include("interface_def.jl")
 function _precompile_()
     ccall(:jl_generating_output, Cint, ()) == 1 || return nothing
 
-    E = JSONRPCEndpoint{Base.PipeEndpoint, Base.PipeEndpoint, JSON.Serializations.StandardSerialization, ContentLengthFraming}
+    E = JSONRPCEndpoint{Base.PipeEndpoint, Base.PipeEndpoint, DefaultJSONSerialization, ContentLengthFraming}
     precompile(start, (E,))
     precompile(send_notification, (E, String, Any))
     precompile(send_request, (E, String, Any))
diff --git a/test/test_json_serialization.jl b/test/test_json_serialization.jl
index 1764eb5d..dc851d72 100644
--- a/test/test_json_serialization.jl
+++ b/test/test_json_serialization.jl
@@ -1,16 +1,19 @@
 @testitem "Custom JSON serialization" setup=[NamedPipes] begin
     using JSON
-    using JSON: StructuralContext, begin_object, show_pair, end_object, show_json, Serializations.StandardSerialization
-
-    struct OurSerialization <: JSON.Serializations.CommonSerialization end
 
     struct OurStruct
         a::String
         b::String
     end
 
-    function JSON.show_json(io::StructuralContext, s::OurSerialization, f::OurStruct)
-        show_json(io, StandardSerialization(), "$(f.a):$(f.b)")
+    @static if isdefined(JSON, :JSONStyle)
+        struct OurSerialization <: JSON.JSONStyle end
+        JSON.StructUtils.lower(::OurSerialization, f::OurStruct) = "$(f.a):$(f.b)"
+    else
+        struct OurSerialization <: JSON.Serializations.CommonSerialization end
+        function JSON.show_json(io::JSON.StructuralContext, ::OurSerialization, f::OurStruct)
+            JSON.show_json(io, JSON.StandardSerialization(), "$(f.a):$(f.b)")
+        end
     end
 
     x = OurStruct("Hello", "World")
diff --git a/test/test_misc.jl b/test/test_misc.jl
index d1c85968..2b87b572 100644
--- a/test/test_misc.jl
+++ b/test/test_misc.jl
@@ -198,7 +198,11 @@ end
     using JSON
     buf = IOBuffer()
     ep = JSONRPC.JSONRPCEndpoint(buf, buf)
-    @test ep.serialization isa JSON.Serializations.StandardSerialization
+    @static if isdefined(JSON, :JSONStyle)
+        @test ep.serialization isa JSON.JSONWriteStyle
+    else
+        @test ep.serialization isa JSON.Serializations.StandardSerialization
+    end
     @test ep.status == JSONRPC.status_idle
     @test ep.err === nothing
     @test ep.read_task === nothing