# Error: Required module \`Ppx\_deriving\_yojson\_runtime' is unavailable

**URL:** <https://discuss.ocaml.org/t/error-required-module-ppx-deriving-yojson-runtime-is-unavailable/1229>\
**Category:** Ecosystem\
**Tags:** ppx\
**Created:** [December 3, 2017, 3:56am UTC](https://discuss.ocaml.org/t/error-required-module-ppx-deriving-yojson-runtime-is-unavailable/1229 "2017-12-03T03:56:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sgrove](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/sgrove/32/152_2.png) [@sgrove](https://discuss.ocaml.org/u/sgrove)\
**Post date:** [December 3, 2017, 3:56am UTC](https://discuss.ocaml.org/t/error-required-module-ppx-deriving-yojson-runtime-is-unavailable/1229/1 "2017-12-03T03:56:37Z")

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Trying to update some dependencies and explore with `http-af`, I’ve hit this error:

```auto
File "_none_", line 1:
Error: Required module `Ppx_deriving_yojson_runtime' is unavailable

```

In my `_tags_ file I have:`true: package(yojson,ppx\_deriving\_yojson)`, and I [see that it’s there](https://github.com/ocaml-ppx/ppx_deriving_yojson/blob/master/src/ppx_deriving_yojson_runtime.mli), and that it’s been there since early 2016 at least, so I don’t understand what I’m missing, or even how to start debugging this.

This is with ocaml 4.04.2, if that helps at all

---

<div class="post-metadata">

**Author:** ![rgrinberg](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/rgrinberg/32/40_2.png) [@rgrinberg](https://discuss.ocaml.org/u/rgrinberg)\
**Post date:** [December 3, 2017, 10:36am UTC](https://discuss.ocaml.org/t/error-required-module-ppx-deriving-yojson-runtime-is-unavailable/1229/2 "2017-12-03T10:36:58Z")

</div>

There’s a `ppx_deriving_yojson.runtime` package that you need to include.