diff --git a/.gitignore b/.gitignore
index 9e6171188..6c043ddef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,4 @@ doc
 # Emacs temporary files
 .#*
 *#
+rebar3
diff --git a/apps/els_lsp/priv/code_navigation/src/diagnostics_sheldon.erl b/apps/els_lsp/priv/code_navigation/src/diagnostics_sheldon.erl
new file mode 100644
index 000000000..63daeb846
--- /dev/null
+++ b/apps/els_lsp/priv/code_navigation/src/diagnostics_sheldon.erl
@@ -0,0 +1,4 @@
+%% Trigger some "somestrange" warnings
+
+%% Trigger some "sheldon" warnings
+-module(diagnostics_sheldon).
diff --git a/apps/els_lsp/src/els_diagnostics.erl b/apps/els_lsp/src/els_diagnostics.erl
index 9c9b4b303..d028b737d 100644
--- a/apps/els_lsp/src/els_diagnostics.erl
+++ b/apps/els_lsp/src/els_diagnostics.erl
@@ -39,12 +39,14 @@
 -callback run(uri())                         -> [diagnostic()].
 -callback source()                           -> binary().
 -callback on_complete(uri(), [diagnostic()]) -> ok.
--optional_callbacks([ on_complete/2 ]).
+-callback init()                             -> ok.
+-optional_callbacks([ on_complete/2, init/0 ]).
 
 %%==============================================================================
 %% API
 %%==============================================================================
--export([ available_diagnostics/0
+-export([ init/0
+        , available_diagnostics/0
         , default_diagnostics/0
         , enabled_diagnostics/0
         , make_diagnostic/4
@@ -55,6 +57,15 @@
 %% API
 %%==============================================================================
 
+-spec init() -> ok.
+init() ->
+  case els_config:get(diagnostics) of
+    undefined ->
+      ok;
+    _ ->
+      init_diagnostics(enabled_diagnostics())
+  end.
+
 -spec available_diagnostics() -> [diagnostic_id()].
 available_diagnostics() ->
   [ <<"bound_var_in_pattern">>
@@ -63,6 +74,7 @@ available_diagnostics() ->
   , <<"dialyzer">>
   , <<"gradualizer">>
   , <<"elvis">>
+  , <<"sheldon">>
   , <<"unused_includes">>
   , <<"unused_macros">>
   , <<"unused_record_fields">>
@@ -146,3 +158,16 @@ valid(Ids0) ->
                                     })
   end,
   Valid.
+
+-spec init_diagnostics([binary()]) -> ok.
+init_diagnostics([]) ->
+  ok;
+init_diagnostics([Id|T]) ->
+  CbModule = cb_module(Id),
+  case erlang:function_exported(CbModule, init, 0) of
+    true ->
+      CbModule:init();
+    false ->
+      ok
+  end,
+  init_diagnostics(T).
diff --git a/apps/els_lsp/src/els_diagnostics_provider.erl b/apps/els_lsp/src/els_diagnostics_provider.erl
index 240d9556c..c185d5e90 100644
--- a/apps/els_lsp/src/els_diagnostics_provider.erl
+++ b/apps/els_lsp/src/els_diagnostics_provider.erl
@@ -42,6 +42,7 @@ options() ->
 
 -spec init() -> state().
 init() ->
+  ok = els_diagnostics:init(),
   #{ in_progress => [] }.
 
 %% LSP 3.15 introduce versioning for diagnostics. Until all clients
diff --git a/apps/els_lsp/src/els_lsp.app.src b/apps/els_lsp/src/els_lsp.app.src
index 5e62a74dd..bf9c720c2 100644
--- a/apps/els_lsp/src/els_lsp.app.src
+++ b/apps/els_lsp/src/els_lsp.app.src
@@ -15,7 +15,8 @@
         getopt,
         erlfmt,
         els_core,
-        gradualizer
+        gradualizer,
+        rebar3_sheldon
     ]},
     {env, []},
     {modules, []},
diff --git a/apps/els_lsp/src/els_sheldon_diagnostics.erl b/apps/els_lsp/src/els_sheldon_diagnostics.erl
new file mode 100644
index 000000000..84230fa2b
--- /dev/null
+++ b/apps/els_lsp/src/els_sheldon_diagnostics.erl
@@ -0,0 +1,124 @@
+%%==============================================================================
+%% Sheldon diagnostics
+%%==============================================================================
+
+-module(els_sheldon_diagnostics).
+
+%%==============================================================================
+%% Behaviours
+%%==============================================================================
+
+-behaviour(els_diagnostics).
+
+%%==============================================================================
+%% Exports
+%%==============================================================================
+
+-export([ init/0
+        , is_default/0
+        , run/1
+        , source/0
+        ]).
+
+%%==============================================================================
+%% Includes
+%%==============================================================================
+
+-include("els_lsp.hrl").
+-include_lib("kernel/include/logger.hrl").
+
+%%==============================================================================
+%% Callback Functions
+%%==============================================================================
+
+-spec init() -> ok.
+init() ->
+  %% By default "sheldon" is not started by reason that he spend few seconds
+  %% to prepare and load dictionary. The "sheldon" shoulld be load only once
+  %% when diagnostic is enabled.
+  application:ensure_all_started(sheldon),
+  ok.
+
+-spec is_default() -> boolean().
+is_default() ->
+  false.
+
+-spec run(uri()) -> [els_diagnostics:diagnostic()].
+run(Uri) ->
+  case els_utils:project_relative(Uri) of
+    {error, not_relative} -> [];
+    RelFile ->
+      try
+        RegEx = "[_@./#&+-=*]",
+        rebar3_sheldon_ast:spellcheck([RelFile], RegEx)
+      of
+        [] -> [];
+        Problems -> format_diagnostics(Problems)
+      catch Type:Error:Stacktrace ->
+        ?LOG_WARNING( "Sheldon error: [type=~p] [error=~p] [stacktrace=~p]"
+                    , [Type, Error, Stacktrace]
+                    ),
+        []
+      end
+    end.
+
+-spec source() -> binary().
+source() ->
+  <<"Sheldon">>.
+
+%%==============================================================================
+%% Internal Functions
+%%==============================================================================
+
+-spec format_diagnostics(any()) -> [map()].
+format_diagnostics(Data) ->
+  R = format_rules(Data),
+  lists:flatten(R).
+
+-spec format_rules([any()]) -> [[map()]].
+format_rules([]) ->
+  [];
+format_rules([#{reason := #{misspelled_words := Miss}} = Data | EItems]) ->
+  ItemDiags = format_item(Miss, Data),
+  [ItemDiags | format_rules(EItems)].
+
+-spec format_item([map()], map()) -> [map()].
+format_item([#{candidates := [], word := Word} | Items], Data) ->
+  #{line := Line, type := Type} = Data,
+  Msg = format_text("The word ~p in ~p is unknown.", [Word, Type]),
+  Diagnostic = diagnostic(Msg, Line, ?DIAGNOSTIC_WARNING),
+  [Diagnostic | format_item(Items, Data)];
+format_item([#{candidates := Candidates, word := Word} | Items], Data) ->
+  #{line := Line, type := Type} = Data,
+  FormatCandidates = format_sheldon_candidates(Candidates, []),
+  Text = "The word ~p in ~p is unknown. Maybe you wanted to use ~ts?",
+  Msg = format_text(Text, [Word, Type, FormatCandidates]),
+  Diagnostic = diagnostic(Msg, Line, ?DIAGNOSTIC_WARNING),
+  [Diagnostic | format_item(Items, Data)];
+format_item([], _) ->
+  [].
+
+-spec diagnostic( any(), integer(),  els_diagnostics:severity()) -> map().
+diagnostic(Msg, Ln, Severity) ->
+  Range   = els_protocol:range(#{from => {Ln, 1}, to => {Ln + 1, 1}}),
+  Message = els_utils:to_binary(Msg),
+  #{ range    => Range
+    , severity => Severity
+    , code     => spellcheck
+    , source   => source()
+    , message  => Message
+    , relatedInformation => []
+    }.
+
+-spec format_sheldon_candidates([any()], [[[any()] | char()]]) -> list().
+format_sheldon_candidates([], Acc) ->
+  Acc;
+format_sheldon_candidates([Candidate], Acc) ->
+  [Acc, format_text("~p", [Candidate])];
+format_sheldon_candidates([Candidate | T], Acc) ->
+  format_sheldon_candidates(T, [Acc, format_text("~p or ", [Candidate])]).
+
+-spec format_text(string(), list()) -> string().
+format_text(Text, Args) ->
+  Formatted = io_lib:format(Text, Args),
+  unicode:characters_to_list(Formatted).
diff --git a/apps/els_lsp/test/els_diagnostics_SUITE.erl b/apps/els_lsp/test/els_diagnostics_SUITE.erl
index 928c82205..e57b1b9d4 100644
--- a/apps/els_lsp/test/els_diagnostics_SUITE.erl
+++ b/apps/els_lsp/test/els_diagnostics_SUITE.erl
@@ -41,6 +41,7 @@
         , unused_macros/1
         , unused_record_fields/1
         , gradualizer/1
+        , sheldon/1
         ]).
 
 %%==============================================================================
@@ -123,6 +124,24 @@ init_per_testcase(TestCase, Config) when TestCase =:= gradualizer ->
   meck:expect(els_gradualizer_diagnostics, is_default, 0, true),
   els_mock_diagnostics:setup(),
   els_test_utils:init_per_testcase(TestCase, Config);
+init_per_testcase(TestCase, Config) when TestCase =:= sheldon ->
+  case list_to_integer(erlang:system_info(otp_release)) >= 23 of
+    true ->
+      meck:new(els_sheldon_diagnostics, [passthrough, no_link]),
+      meck:expect(els_sheldon_diagnostics, is_default, 0, true),
+      els_mock_diagnostics:setup(),
+      meck:expect( els_diagnostics_provider
+                 , init
+                 , fun() ->
+                      DiagnosticsConfig = #{"enabled" => [<<"sheldon">>]},
+                      els_config:set(diagnostics, DiagnosticsConfig),
+                      meck:passthrough([])
+                   end
+                 ),
+      els_test_utils:init_per_testcase(TestCase, Config);
+    false ->
+      {skip, "Sheldon diagnostics should run on OTP23+"}
+  end;
 init_per_testcase(TestCase, Config) ->
   els_mock_diagnostics:setup(),
   els_test_utils:init_per_testcase(TestCase, Config).
@@ -164,6 +183,11 @@ end_per_testcase(TestCase, Config) when TestCase =:= gradualizer ->
   els_test_utils:end_per_testcase(TestCase, Config),
   els_mock_diagnostics:teardown(),
   ok;
+end_per_testcase(TestCase, Config) when TestCase =:= sheldon ->
+  meck:unload(els_sheldon_diagnostics),
+  els_test_utils:end_per_testcase(TestCase, Config),
+  els_mock_diagnostics:teardown(),
+  ok;
 end_per_testcase(TestCase, Config) ->
   els_test_utils:end_per_testcase(TestCase, Config),
   els_mock_diagnostics:teardown(),
@@ -654,6 +678,36 @@ gradualizer(_Config) ->
   Hints = [],
   els_test:run_diagnostics_test(Path, Source, Errors, Warnings, Hints).
 
+-spec sheldon(config()) -> ok.
+sheldon(_Config) ->
+  {ok, Cwd} = file:get_cwd(),
+  RootPath = els_test_utils:root_path(),
+  try
+      file:set_cwd(RootPath),
+      Path = src_path("diagnostics_sheldon.erl"),
+      Source = <<"Sheldon">>,
+      Errors = [],
+      Warnings = [ #{ code => spellcheck
+                    , message => <<"The word \"sheldon\" in "
+                                   "comment is unknown. "
+                                   "Maybe you wanted to use \"Sheldon\"?">>
+                    , range => {{2, 0}, {3, 0}}
+                    , relatedInformation => []
+                    }
+                 , #{ code => spellcheck
+                    , message => <<"The word \"somestrange\" in comment is "
+                                    "unknown.">>
+                    , range => {{0, 0}, {1, 0}}
+                    , relatedInformation => []
+                    }
+                 ],
+      Hints = [],
+      els_test:run_diagnostics_test(Path, Source, Errors, Warnings, Hints)
+  catch _Err ->
+      file:set_cwd(Cwd)
+  end,
+  ok.
+
 %%==============================================================================
 %% Internal Functions
 %%==============================================================================
diff --git a/rebar.config b/rebar.config
index aa7377986..363d3b5bb 100644
--- a/rebar.config
+++ b/rebar.config
@@ -17,6 +17,7 @@
        , {tdiff,         "0.1.2"}
        , {uuid,          "2.0.1", {pkg, uuid_erl}}
        , {gradualizer, {git, "https://github.com/josefs/Gradualizer.git", {ref, "e93db1c"}}}
+       , {rebar3_sheldon, "0.4.2"}
        ]
 }.
 
diff --git a/rebar.lock b/rebar.lock
index 36a73a456..2db3ef0a8 100644
--- a/rebar.lock
+++ b/rebar.lock
@@ -14,9 +14,12 @@
  {<<"providers">>,{pkg,<<"providers">>,<<"1.8.1">>},1},
  {<<"quickrand">>,{pkg,<<"quickrand">>,<<"2.0.1">>},1},
  {<<"rebar3_format">>,{pkg,<<"rebar3_format">>,<<"0.8.2">>},0},
+ {<<"rebar3_sheldon">>,{pkg,<<"rebar3_sheldon">>,<<"0.4.2">>},0},
  {<<"redbug">>,{pkg,<<"redbug">>,<<"2.0.6">>},0},
+ {<<"sheldon">>,{pkg,<<"sheldon">>,<<"0.4.1">>},1},
  {<<"tdiff">>,{pkg,<<"tdiff">>,<<"0.1.2">>},0},
  {<<"uuid">>,{pkg,<<"uuid_erl">>,<<"2.0.1">>},0},
+ {<<"worker_pool">>,{pkg,<<"worker_pool">>,<<"5.1.0">>},2},
  {<<"yamerl">>,{pkg,<<"yamerl">>,<<"0.8.1">>},0},
  {<<"zipper">>,{pkg,<<"zipper">>,<<"1.0.1">>},1}]}.
 [
@@ -32,9 +35,12 @@
  {<<"providers">>, <<"70B4197869514344A8A60E2B2A4EF41CA03DEF43CFB1712ECF076A0F3C62F083">>},
  {<<"quickrand">>, <<"6D861FA11E6EB51BB2343A2616EFF704C2681A9997F41ABC78E58FA76DA33981">>},
  {<<"rebar3_format">>, <<"2D64DA61E0B87FCA6C4512ADA6D9CBC2B27ADC9AE6844178561147E7121761BD">>},
+ {<<"rebar3_sheldon">>, <<"DC69F6A5BA5B7AD8A547F656DF25DFE41E030DF2787467F5433A3210AE7FDB0C">>},
  {<<"redbug">>, <<"A764690B012B67C404562F9C6E1BA47A73892EE17DF5C15F670B1A5BF9D2F25A">>},
+ {<<"sheldon">>, <<"1413143F9D96D30C6A18DD6746B5183F048B23AC345FF3BB92B399A5A69EBE93">>},
  {<<"tdiff">>, <<"4E1B30321F1B3D600DF65CD60858EDE1235FE4E5EE042110AB5AD90CD6464AC5">>},
  {<<"uuid">>, <<"1FD9079C544D521063897887A1C5B3302DCA98F9BB06AADCDC6FB0663F256797">>},
+ {<<"worker_pool">>, <<"61BA970F856AF8B2D85232ADC8E4B990FA1719F396FCDAD954702946395ADD80">>},
  {<<"yamerl">>, <<"07DA13FFA1D8E13948943789665C62CCD679DFA7B324A4A2ED3149DF17F453A4">>},
  {<<"zipper">>, <<"3CCB4F14B97C06B2749B93D8B6C204A1ECB6FAFC6050CACC3B93B9870C05952A">>}]},
 {pkg_hash_ext,[
@@ -49,9 +55,12 @@
  {<<"providers">>, <<"E45745ADE9C476A9A469EA0840E418AB19360DC44F01A233304E118A44486BA0">>},
  {<<"quickrand">>, <<"14DB67D4AEF6B8815810EC9F3CCEF5E324B73B56CAE3687F99D752B85BDD4C96">>},
  {<<"rebar3_format">>, <<"CA8FF27638C2169593D1449DACBE8895634193ED3334E906B54FC97F081F5213">>},
+ {<<"rebar3_sheldon">>, <<"19120875183E6EE7C11EC21FC99B12347A37F59386DB7A4759DBBA55EA621D4C">>},
  {<<"redbug">>, <<"AAD9498671F4AB91EACA5099FE85A61618158A636E6286892C4F7CF4AF171D04">>},
+ {<<"sheldon">>, <<"15E24EDDCDB42FE07AA7913DA770DBCE4EE052A37AA76E467748D4C977F463C9">>},
  {<<"tdiff">>, <<"E0C2E168F99252A5889768D5C8F1E6510A184592D4CFA06B22778A18D33D7875">>},
  {<<"uuid">>, <<"AB57CACCD51F170011E5F444CE865F84B41605E483A9EFCC468C1AFAEC87553B">>},
+ {<<"worker_pool">>, <<"59A975728E5C2B69A23D1C5EBC3B63251EC4ACBF4E9D25F1C619E3AD4B550813">>},
  {<<"yamerl">>, <<"96CB30F9D64344FED0EF8A92E9F16F207DE6C04DFFF4F366752CA79F5BCEB23F">>},
  {<<"zipper">>, <<"6A1FD3E1F0CC1D1DF5642C9A0CE2178036411B0A5C9642851D1DA276BD737C2D">>}]}
 ].