---
title: "Get the public signing key."
method: GET
path: "/api/signing-key"
tags: ["Signing"]
---

# Get the public signing key.

`GET /api/signing-key`

Returns the operator's ES256 (ECDSA P-256) public signing key in PEM, JWK, and fingerprint form. Use the public key to verify the `X-Philter-Signature` JWT header returned on successful `POST /api/filter` and `POST /api/explain` responses when output signing is enabled. This endpoint does not require authentication.

## Response `200`

Public signing key details.

- string

## Other responses

- `400` — Bad Request
- `401` — Unauthorized
- `413` — Content Too Large
- `415` — Unsupported Media Type
- `500` — Internal Server Error
- `503` — Service Unavailable

---

[API](https://skmtc.net/philterd/apis/philter-api.md) · [All operations](https://skmtc.net/philterd/apis/philter-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/philterd/philter-api/versions/67443cd5a65b/schema)