---
title: "Recover an accepted Hub `rfd3` request. New launches return HTTP 410 `hub_execution_retired`; use `/v2/zencloud`."
method: POST
path: "/v2/hub/rfd3/start"
tags: ["Hub"]
---

# Recover an accepted Hub \`rfd3\` request. New launches return HTTP 410 \`hub_execution_retired\`; use \`/v2/zencloud\`.

`POST /v2/hub/rfd3/start`

## Request

- Base URL: `https://api.omtx.ai` (the document declares no server; this is the origin it was published from)
- URL: `https://api.omtx.ai/v2/hub/rfd3/start`
- Auth: one of:
  - API key in header `x-api-key`
  - HTTP bearer

## Headers

- `Idempotency-Key` string, required

## Request body

- object: RFD3 protein structure design.
  - `job_name` string: Human-readable RFD3 job name
  - `pdb_artifact_id` string, uuid, required: Uploaded target structure artifact UUID (.pdb/.ent)
  - `design_mode` 'ppi_binder' | 'small_molecule_binder' | 'na_binder', required: Canonical RFD3 design mode. Use ppi_binder for protein interface design, small_molecule_binder for ligand-conditioned design, and na_binder for nucleic-acid-conditioned design.
  - `contig` string, required: Foundry contig string for design topology and fixed motif selection.
  - `length` string, nullable: Optional Foundry length constraint string (for example 190-270).
  - `hotspot_selection` string, nullable: Hotspot selector string for ppi_binder mode. Use either JSON dict syntax or semicolon format like 'E64:CD2,CZ;E88:CG,CZ'.
  - `ligand` string, nullable: Ligand identifier present in the uploaded input structure (for example CCD code IAI). Required for small_molecule_binder.

## Response `200`

Successful Response

- unknown

## Other responses

- `202`: Job accepted. Poll /v2/jobs/{job_id} for status/result.

---

[API](https://skmtc.dev/omtx/apis/gateway.md) - [All operations](https://skmtc.dev/omtx/apis/gateway/llms.txt) - [OpenAPI document](https://skmtc.dev/omtx/apis/gateway/revisions/232715a75205?raw)