<<194, 160>> is U+00A0, a no breaking space.

According to RFC 7159 it is not valid whitespace:

      ws = *(
             %x20 /              ; Space
             %x09 /              ; Horizontal tab
             %x0A /              ; Line feed or New line
             %x0D )              ; Carriage return

Hi guys, thanks for yor help, finally i have found the solution. The problem is my jason contains tab character. So what i have to do is just clear any additional character like newline or tab from:

"{   \"topic\": \"room:marketplace_disbursement_service\",   \"event\": \"inquiry_response\",   \"payload\": {},   \"ref\": 0 }"

to this one:

"{\"topic\":\"room:marketplace_disbursement_service\",\"event\":\"inquiry_response\",\"ref\":0}"

and it works , thanks guys for helping me that the problem is jason

That does look like a bug if Jason doesn’t accept 0x09 as whitespace character. The JSON standard certainly suggests it should be valid. Perhaps submit a bug report?

It seems discourse replaces the 0x09 with space characters which is why my copy/paste of your snippet parsed ok.

Copy/pasted what you put and it works fine:

iex()50> a = "    {    \"a\": \"first\"    , \"b\": \"last\",        \"c\": {}        }"
"    {    \"a\": \"first\"    , \"b\": \"last\",        \"c\": {}        }"
iex()51> Jason.decode(a)
{:ok, %{"a" => "first", "b" => "last", "c" => %{}}}

Throwing in some random tabs is still fine too:

iex()52> a = " \t   {  \t  \"a\": \t\"first\"  \t  ,\t \"b\": \"last\",     \t   \"c\": {} \t
 }"
" \t   {  \t  \"a\": \t\"first\"  \t  ,\t \"b\": \"last\",     \t   \"c\": {} \t       }"
iex()53> Jason.decode(a)
{:ok, %{"a" => "first", "b" => "last", "c" => %{}}}

Are you ‘sure’ your IDE/sublime is not adding in some weird invalid unicode stuff or so? What if you take your not-working json string and assign it to a then run this:

inspect(a, binaries: :as_binaries)

What is the result of that please?

it returns like below:

"<<123, 32, 194, 160, 194, 160, 34, 116, 111, 112, 105, 99, 34, 58, 32, 34, 114, 111, 111, 109, 58, 109, 97, 114, 107, 101, 116, 112, 108, 97, 99, 101, 95, 100, 105, 115, 98, 117, 114, 115, 101, 109, 101, 110, 116, 95, 115, 101, 114, 118, ...>>"