Quickstart

One URL, one header, and a JSON body that names an input and the operations to run. The steps below take about five minutes.

Get an API key

Request access and, once your account is provisioned, copy your key from the dashboard. Keys look like chrs_live_.... You see yours once, at creation, so store it now.

export CHERSUS_KEY=chrs_live_YOUR_KEY

Make your first run

Every request goes to POST /v1/run. This one redacts personal data from a sentence:

curl -X POST https://api.chersus.com/v1/run \
-H "Authorization: Bearer $CHERSUS_KEY" \
-H "Content-Type: application/json" \
-d '{
  "input": "Contact Jane Doe at jane.doe@example.com about invoice #4821.",
  "transform": ["pii.redact"]
}'

const res = await fetch("https://api.chersus.com/v1/run", {
method: "POST",
headers: {
  Authorization: "Bearer " + process.env.CHERSUS_KEY,
  "Content-Type": "application/json",
},
body: JSON.stringify({
  input: "Contact Jane Doe at jane.doe@example.com about invoice #4821.",
  transform: ["pii.redact"],
}),
});

const data = await res.json();

import os

import requests

res = requests.post(
  "https://api.chersus.com/v1/run",
  headers={"Authorization": "Bearer " + os.environ["CHERSUS_KEY"]},
  json={
      "input": "Contact Jane Doe at jane.doe@example.com about invoice #4821.",
      "transform": ["pii.redact"],
  },
)

data = res.json()

Read the result

{
  "trace_id": "chs_01J9X4Q7K2M8N3P5R6T7V8W9X0",
  "status": "completed",
  "decision": "allow",
  "output": "Contact [REDACTED] at [REDACTED] about invoice #4821.",
  "transform": [{ "op": "pii.redact", "changes": 2 }],
  "usage": {
    "billed": { "unit": "characters", "input": 61, "output": 53, "quantity": 114 }
  },
  "audit": {
    "region": "eu-nl-1",
    "retention": "none",
    "total_ms": 26
  }
}

Operations come in three kinds. A transform rewrites the input, a detect returns a verdict and a score, and an extract returns structured data. Handle those three shapes once and you can call any operation.

decision tells you whether to carry on. usage.billed shows 61 characters in, 53 handed back and 114 billed. The audit trace holds hashes, never content.

Relay your first prompt

Add a relay and the same call makes the model call too. Send your provider key in X-LLM-Key, and the answer comes back rehydrated in one response.

curl -X POST https://api.chersus.com/v1/run \
  -H "Authorization: Bearer $CHERSUS_KEY" \
  -H "X-LLM-Key: $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": "Hi, I am Jane Doe. Can you check invoice #4821?",
    "transform": ["pii.tokenize"],
    "relay": { "provider": "openai", "model": "gpt-4.1-mini" }
  }'

Next

• Workflows: combine detects, extracts and transforms, add conditions and routing.
• Calling your model: relay, the gateway, and your own model call.
• Policies: save a workflow under a name and version it.
• Operations: every operation with an example.
• API reference: fields, errors, rate limits and billing.

The first 1M characters a month are free, no payment method needed.