---
title: "read: value chain"
description: "Reads the value chain of one vertical, with the brand whose participants are placed on it to The answer gives the chain's stocks and handovers with their counts, the participants on each stock, and the loops the templates name over it"
section: reference
address: /reference/read/value_chain
contract: 0476e35e6e275db5
---
# read: value chain
Reads the value chain of one vertical, with the brand whose participants are placed on it to The answer gives the chain's stocks and handovers with their counts, the participants on each stock, and the loops the templates name over it
[figure: The caller sends ValueChainInput to /v1/read/value_chain. The platform returns a card whose body is ValueChain.]
POST/v1/read/value_chain
Read the value chain. The call needs the brand rung under a token with the read grant, and it is served by either, by the size bound.
The route takes [ValueChainInput](/concepts/valuechaininput) and returns a card whose body is [ValueChain](/concepts/valuechain).
## Request body
The request body is [ValueChainInput](/concepts/valuechaininput).
| field | type | required | note |
|---|---|---|---|
| `vertical` | `id` | yes | |
| `brand` | `id` | no | |
| `segment` | `id` | no | |
## Response
The route returns a card whose body is [ValueChain](/concepts/valuechain). Every card ends with a foot that states the basis of each number, the scope of the call, and the time when the facts were true.
## Headers
| header | required | meaning |
|---|---|---|
| `Scale-Scope` | yes | the scope the call runs in: tenant/, then /brand/, then /strategy/ |
| `Scale-As-True-On` | no | the date the facts must have been true on; defaults to now |
| `Scale-As-Known-On` | no | the date the facts must have been known on; defaults to now |
| `Scale-Key` | no | for a change, the key made from the input; a repeat under the same key returns the unit held and writes nothing |
A caller needs the brand rung and a token with the read grant. The platform or the desktop app serves this route.
## Example
The example sends the smallest body that ValueChainInput allows. The build validates it against the schema of ValueChainInput.
Example
```sh
curl -X POST https://api.scaleintelligence.co/v1/read/value_chain \
-H "Scale-Key: $SCALE_KEY" -H "Scale-Scope: tenant/" \
-H "content-type: application/json" \
-d '{ "vertical": "…" }'
```
```typescript
import { client } from "@scale/sdk";
const answer = await client.read.value_chain({
"vertical": "…"
});
// answer.body is a ValueChain. answer.foot holds the basis, the scope and the time.
```
```python
import requests
answer = requests.post("https://api.scaleintelligence.co/v1/read/value_chain",
headers={"Scale-Key": KEY, "Scale-Scope": "tenant/"},
json={
"vertical": "…"
}).json()
```
```rust
let answer: Card = client.post("https://api.scaleintelligence.co/v1/read/value_chain")
.header("Scale-Key", key).header("Scale-Scope", "tenant/")
.json(&ValueChainInput { /* the fields of the page */ }).send().await?.json().await?;
```