name: arolsen-archives description: | Search Arolsen Archives (collections.arolsen-archives.org) — the world's largest collection of documents on victims of Nazi persecution, ~30M names across concentration camps, forced labor, DP records, and ITS tracing files. Free, no account needed. Uses the site's JSON-over- HTTP ASMX backend directly — no browser. Use this skill for WWII-era research: forced labor, deportations, concentration camp records, Amersfoort/Vught/Westerbork transit camp inmates, displaced persons, ITS tracing. Directly relevant for Herman Knijf (Neuengamme / forced-labor trail) and any ancestor moved through a Nazi-era administrative system. Tier A evidence (primary-source camp documents with downloadable scans).

Arolsen Archives — Nazi persecution records

The International Tracing Service (ITS), now the Arolsen Archives, holds ~30M documents on persons persecuted by the Nazi regime: concentration camp lists, forced labor cards, DP registrations, Gestapo files, post-war tracing requests. The web collection at collections.arolsen-archives.org is free and fully open — no account, no paywall, no rate limit observed.

Access method

JSON-over-HTTP ASMX backend at https://collections-server.arolsen-archives.org/ITS-WS.asmx/. The Angular SPA is a thin client over this legacy IIS/ASMX service. Plain curl works — no Playwright needed.

CORS-open. All endpoints need Content-Type: application/json and Origin: https://collections.arolsen-archives.org.

Critical gotcha: the server holds query state under an ASP.NET_SessionId cookie. You must persist cookies across calls with curl -c jar.txt -b jar.txt, or GetPersonList returns {"d":[]} even for common names.

Responses are wrapped in {"d": ...}. Decode d as the real payload.

Workflow (verified end-to-end)

1. Build the query

curl -c /tmp/arolsen.jar -b /tmp/arolsen.jar \
  -X POST 'https://collections-server.arolsen-archives.org/ITS-WS.asmx/BuildQueryGlobalForAngular' \
  -H 'Content-Type: application/json' \
  -H 'Origin: https://collections.arolsen-archives.org' \
  -d '{"uniqueId":"abc123","lang":"en","archiveIds":[],"strSearch":"Knijf","synSearch":true}'

synSearch:true enables phonetic variants — always use it for Dutch surnames (German clerks transcribed them phonetically: Knyf, Kneyff, Knejf, de Knijf, de Knyf).

2. Count hits

curl -c /tmp/arolsen.jar -b /tmp/arolsen.jar \
  -X POST 'https://collections-server.arolsen-archives.org/ITS-WS.asmx/GetCount' \
  -H 'Content-Type: application/json' \
  -H 'Origin: https://collections.arolsen-archives.org' \
  -d '{"uniqueId":"abc123","lang":"en","searchType":"person","useFilter":false}'
# -> {"d":"18"}

Unfiltered GetCount returns 33708578 — the real total name index.

3. Fetch results

curl -c /tmp/arolsen.jar -b /tmp/arolsen.jar \
  -X POST 'https://collections-server.arolsen-archives.org/ITS-WS.asmx/GetPersonList' \
  -H 'Content-Type: application/json' \
  -H 'Origin: https://collections.arolsen-archives.org' \
  -d '{"uniqueId":"abc123","lang":"en","rowNum":0,"orderBy":"LastName","orderType":"asc"}'

Returns person list with ObjId, DescId, dates, places, signature.

4. Per-record detail + scans

# Document detail (no cookie needed)
curl -X POST 'https://collections-server.arolsen-archives.org/ITS-WS.asmx/GetFileByObj' \
  -H 'Content-Type: application/json' \
  -d '{"objId":"76567490","lang":"en"}'

# Archive-series context
curl -X POST 'https://collections-server.arolsen-archives.org/ITS-WS.asmx/GetArchiveInfo' \
  -H 'Content-Type: application/json' \
  -d '{"descId":"915146","level":1,"lang":"en"}'

5. Download scans directly

Scan images are served from https://collections-server.arolsen-archives.org/G/SIMS1/SIMS3/.../NNN.jpg with no auth, no cookie. You can pipe them straight into private/sources/ attached to a Tier A finding.

Human-readable URLs for reference in findings:

https://collections.arolsen-archives.org/en/search/person/{ObjId}?s={query}&t={DescId}&p=0
https://collections.arolsen-archives.org/en/document/{ObjId}

Verified example — Knijf search

18 Knijf persons found including:

• Cornelius KNEJF KNIJF b. 23 Apr 1923, Amsterdam — signature 7.5.7 Bundesarchiv "foreigners employed on former Reich territory", unit 7648000145 "Jensen–Kuznetsow", subject index: Forced labour. ObjId 76567490, 2 scan pages, direct JPG download confirmed.
• Theodorus KNIJF b. 2 Aug 1920, prisoner #9331 — signature 1.1.1.2 Amersfoort Police Transit Camp individual prisoner files.
• Christianus KNIJF b. 5 Mar 1907 — signature 2.1.1.1.

The Amersfoort transit camp series and forced-labor series both have Knijf hits — directly relevant to the Herman Knijf hardening workflow.

Signature cheatsheet (top-level series)

Full schema at collections.arolsen-archives.org/en/archive — but all endpoints return the signature in the record, so you rarely need it.

Output format

**Source:** Arolsen Archives — {signature} {series name}
**Person:** {LastName} {FirstName} b. {date}, {place of birth}
**ObjId:** {ObjId}
**DescId:** {DescId}
**Document:** https://collections.arolsen-archives.org/en/document/{ObjId}
**Scan URLs:** {direct JPG links}
**Confidence:** Tier A — primary source scan of original camp/forced-labor
administrative document

Limitations

• Session cookie is load-bearing — #1 foot-gun. Persist it across all four call phases.
• Dutch surnames are transcribed phonetically by German clerks — always search with synSearch:true and try multiple spellings (Knyf, Kneyff, de Knijf, de Knyf).
• No OpenAPI / Swagger — endpoints were reverse-engineered from the Angular SPA. They may change, but are currently stable.
• Legacy ASMX, not REST — responses wrapped in {"d": ...}.