# Call external API json body POST
**URL:** https://forum.flowable.org/t/call-external-api-json-body-post/8793
**Category:** Flowable Engine
**Created:** [December 28, 2021, 2:48pm UTC](https://forum.flowable.org/t/call-external-api-json-body-post/8793 "2021-12-28T14:48:08Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@gurucube](https://forum.flowable.org/u/gurucube)
#### Post date: [December 28, 2021, 2:48pm UTC](https://forum.flowable.org/t/call-external-api-json-body-post/8793/1 "2021-12-28T14:48:08Z")
Hello,
I need to call an external API from a flowable process sending a JSON formatted body.
So I created a process and defined:
requestURL: and filled with the cURL to reach
requestBody: and placed my json
requestHeaders: and added Content-Type: application/json
also, I’ve found somewhere instructions to specify this into the same json ${“name”:“signPDF”,“type”:“json”,“value”: {
Anyway when I call the /runtime/process-instances passing the right processDefinitionId then I get this error:
{
“message”: “Internal server error”,
“exception”: "Unknown property used in expression: {\n “AccountCredentials”: {\n “oneshot”: 0,\n …
It is like somewhere I should specify that the body is a JSON but where?
Someone could point me into the right direction?
Thank you
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### Author:  [@gurucube](https://forum.flowable.org/u/gurucube)
#### Post date: [December 28, 2021, 6:10pm UTC](https://forum.flowable.org/t/call-external-api-json-body-post/8793/2 "2021-12-28T18:10:27Z")
Fixed: The process is correct just need to escape $ that is used in some fields. Thanks!