diff --git a/src/ctbase.jl b/src/ctbase.jl
new file mode 100644
index 00000000..1709d39b
--- /dev/null
+++ b/src/ctbase.jl
@@ -0,0 +1,74 @@
+# Olivier, tu as ici l'extension qui fait les sauvergardes / lectures de solution en format julia (jld2) et texte (json). Le load/save est assez trivial, mais on pourrait unifier avec le json en ajoutant un argument format=:jld [:json]. Cette extension irqit ensuite dans CTBase typiquement vu que l'aspect direct n'intervient pas
+
+module CTDirectExt
+
+using CTDirect
+using CTBase
+using DocStringExtensions
+
+using JLD2  # load / save
+using JSON3 # read / export
+
+"""
+$(TYPEDSIGNATURES)
+  
+Save OCP solution in JLD2 format
+"""
+function JLD2.save(sol::OptimalControlSolution; filename_prefix = "solution")
+    save_object(filename_prefix * ".jld2", sol)
+    return nothing
+end
+
+"""
+$(TYPEDSIGNATURES)
+     
+Load OCP solution in JLD2 format
+"""
+function JLD2.load(filename_prefix = "solution")
+    return load_object(filename_prefix * ".jld2")
+end
+
+"""
+$(TYPEDSIGNATURES)
+  
+Export OCP solution in JSON format
+"""
+function CTDirect.export_ocp_solution(sol::OptimalControlSolution; filename_prefix = "solution")
+    # fuse into save ?
+    blob = Dict(
+        "objective" => sol.objective,
+        "time_grid" => sol.time_grid,
+        "state" => state_discretized(sol),
+        "control" => control_discretized(sol),
+        "costate" => costate_discretized(sol)[1:(end - 1), :],
+        "variable" => sol.variable,
+    )
+    open(filename_prefix * ".json", "w") do io
+        JSON3.pretty(io, blob)
+    end
+    return nothing
+end
+
+"""
+$(TYPEDSIGNATURES)
+  
+Read OCP solution in JSON format
+"""
+function CTDirect.import_ocp_solution(ocp::OptimalControlModel; filename_prefix = "solution")
+    # fuse into load ? 
+    json_string = read(filename_prefix * ".json", String)
+    blob = JSON3.read(json_string)
+
+    # NB. convert vect{vect} to matrix
+    return OptimalControlSolution(
+        ocp,
+        blob.time_grid,
+        stack(blob.state, dims = 1),
+        stack(blob.control, dims = 1),
+        blob.variable,
+        stack(blob.costate, dims = 1);
+        objective = blob.objective,
+    )
+end
+
+end