---
title: "Resolve DUNS ↔ UEI"
method: GET
path: "/api/v1/identifiers/{identifier}"
tags: ["Identifiers"]
---

# Resolve DUNS ↔ UEI

`GET /api/v1/identifiers/{identifier}`

## Request

- Base URL: `https://govconapi.com` (the document declares no server; this is the origin it was published from)
- URL: `https://govconapi.com/api/v1/identifiers/{identifier}`
- Auth: HTTP bearer

Free reverse lookup between legacy DUNS (9 digits, or 13-digit DUNS+4) and current UEI (12 alphanumeric). Accepts either side; returns both plus the entity name and FFATA evidence count.

**Coverage truth.** The crosswalk is built from FFATA Section 2 subaward filings since FY2025, where both identifiers co-exist on the same record. A 404 here means *not in the FFATA-derived crosswalk* (about 24K firms indexed), not *not in SAM*. The official SAM DUNS↔UEI translator is admin-gated and not publicly available.

## Path parameters

- `identifier` string, required

## Response `200`

Pair found. Returns DUNS, UEI, entity name, evidence count, last seen.

- unknown

## Other responses

- `404`: Identifier not in the FFATA-derived crosswalk.
- `422`: Identifier shape invalid (not 9-digit DUNS, not 12-char UEI).
- `429`: Rate limit exceeded.

---

[API](https://skmtc.dev/govconapi/apis/govcon-api.md) · [All operations](https://skmtc.dev/govconapi/apis/govcon-api/llms.txt) · [OpenAPI document](https://skmtc.dev/govconapi/apis/govcon-api/revisions/32e498016218?raw)