questcomp.com logo
questcomp.com

find-electronic-components

Installation

Adds this website's skill for your agents

 

Summary

Look up electronic components on questcomp.com by manufacturer part number and extract live unit price, stock quantity, datasheet URL, and specs as machine-readable JSON. Uses the site's JSON autocomplete PageMethod for search and the static JSON-LD-bearing /part/ detail pages for extraction.

FIG. 01
FIG. 02
FIG. 03
FIG. 04
FIG. 05
SKILL.md
219 lines

Quest Components Part Lookup & Extraction

Purpose

Look up electronic components on questcomp.com (Quest Components — a US independent stocking distributor of hard-to-find, obsolete, and allocated parts) by manufacturer part number (MPN) and return machine-readable JSON containing live unit price, stock quantity, datasheet URL, description/specs, and the canonical detail URL. This skill is read-only (no account, cart, quote, or purchase actions — it only locates those paths). Everything it extracts — price, stock, datasheet, specs — is public and renders logged out; no field is behind a login wall. Prices are USD (single US locale; no region switch).

When to Use

  • Resolving one or more exact MPNs (e.g. SN74LS00N, LM358N, 2N2222A) to a Quest detail page with live pricing/stock.
  • "Search" by a partial part number (e.g. 74LS00, LM358) to enumerate the matching MPN family Quest stocks.
  • Checking availability/pricing of obsolete / allocated / hard-to-find parts, including zero-stock parts that are quote-only.
  • Programmatic BOM pricing where you already have vendor MPNs.

Do not use this skill for descriptive/parametric spec search ("10uF tantalum capacitor", "obsolete 74LS logic IC") — the main site cannot do that (see Gotchas). Route those to the CSE subdomain noted below.

Workflow

Quest is an ASP.NET WebForms site. The cheapest, most reliable path is not to drive the search UI (its result grid is a __doPostBack UpdatePanel with no URL-addressable state). Instead use the site's own public JSON PageMethod for search, then fetch the server-rendered detail page and read its JSON-LD. All endpoints below are anonymous (no auth, no cookies required for reads) and not disallowed by robots.txt.

Base host: https://www.questcomp.com (the bare questcomp.com and /search/... both 301 — always use www). A bare Browserbase/HTTP session with a normal browser UA is sufficient; no stealth, no residential proxy, no --verified were required (site returned 200s to plain fetches; anti-bot probe: none detected).

Step 1 — Search (part number → candidate MPNs + detail URLs)

POST https://www.questcomp.com/baseform.aspx/searchpartsforautocomplete

Content-Type: application/json; charset=utf-8
Body: {"pn":"<query>","searchByMyPn":"0"}

Response is an ASP.NET PageMethod envelope {"d":"<xml-string>"}. The inner string is a <NewDataSet> of <Table> rows, each with:

  • <MasterPartID> — Quest's internal part id (last path segment of the detail URL).
  • <PartNumber> — the MPN.
  • <IsStock> — Yes / No (in-stock flag).
  • <Url> — relative detail URL, e.g. /part/4/sn74ls00n/382914397.

Behavior (verified):

  • Case-insensitive substring match on the MPN string, capped at 16 rows. 74LS → 74LS00, 74LS00A, 74LS00B1, .... An exact MPN comes back as the first row plus near-variants (SN74LS00N, SN74LS00N-00, SN74LS00N-10, ...).
  • A single-token match on a value that happens to appear inside part numbers works (10uF returns 16 rows whose MPNs contain 10UF), but multi-word descriptive phrases return nothing — spaces are treated literally and never match an MPN.
  • Empty result = exactly {"d":""} (32 bytes). This is the authoritative "no such part number" signal — treat it as an empty result set with a note, not an error.

If you specifically want the site's own ranked grid with sorting/pagination/CSV export, drive the postback instead (see Browser fallback) — it returns the same MPN set as this API.

Step 2 — Extract (detail page → price / stock / specs / datasheet)

Plain GET https://www.questcomp.com/part/{cat}/{mpn}/{id} (from <Url> above). Fully server-rendered static HTML — no JS, no login. Extract:

  1. JSON-LD (<script type="application/ld+json">, the "@type":"product" block) — the clean machine-readable core:
    • mpn, description (Quest's spec string, e.g. "DUAL OP-AMP, 9000uV OFFSET-MAX, 1.1MHz BAND WIDTH, PDIP8"), category, image.
    • offers.lowPrice — lowest unit price across all offers and quantity breaks → use as unit_price.
    • offers.priceCurrency — "USD".
    • offers.offerCount — number of distinct offers on the page.
  2. Total stock — the "<N> parts available" string in the page body (e.g. 2,515 parts available) → use as stock_qty (total in-stock across all offers). If absent, stock is 0.
  3. Per-offer grid (only if you need per-manufacturer breakdown): the page aggregates multiple manufacturer offers (e.g. SN74LS00N = 26 offers: Motorola, Texas Instruments, ON Semiconductor…). Each offer row carries: manufacturer name, Part Status (ACTIVE / TRANSFERRED / DISCONTINUED), RoHS/REACH flags, available qty, ship date, qty-break prices, and Min Qty. Manufacturer values are in hidden inputs value="Manufacturer;<name>". Set the top-level manufacturer field to null (reason "multiple_offers:<offerCount>") when offerCount > 1 — do not pick one and infer it is "the" manufacturer. When offerCount == 1, report that sole manufacturer.

Step 3 — Datasheet URL (optional, session-bound)

Datasheet anchors on the detail page carry data-dsid='<DatasheetID>;<ObjectID>'. Resolve to a real PDF URL via:

POST https://www.questcomp.com/productcategorylisting.aspx/getdatasheeturl

Content-Type: application/json; charset=utf-8
Body: {"dsID":"<data-dsid value>","dsUser":"<hfDsUser value>"}
  • dsUser is the value of the hidden input id$=hfDsUser on the loaded detail page — it is a session-bound token of the form "0;<GUID>;<client-IP>". You must read it from the same page render; a stale/absent dsUser yields HTTP 500.
  • Response {"d":"<url>"} is a direct PDF (Quest proxies IHS/Accuris datasheets, e.g. https://4donline.ihs.com/images/VipMasterIC/.../MOTOS12583-1.pdf?hkey=...).
  • Because dsUser requires a live page context, datasheet resolution is the one step that benefits from a browser session (read hfDsUser + the data-dsids via browse eval, then fetch() from the page origin). If you cannot resolve it, return datasheet_url: null with reason "datasheet_requires_session_dsuser".

Step 4 — Assemble output

Emit one JSON object per query in exactly this shape (any non-public/unavailable field = null with a reason flag; never infer):

{"query","method","source","results":[{"mpn","manufacturer","description","unit_price","currency","stock_qty","datasheet_url","detail_url","checked"}],"note"}

checked = ISO-8601 UTC timestamp of extraction. source = the exact endpoint/URL used. See Expected Output for every outcome shape.

Browser fallback (site's own search grid)

Use only if you want Quest's ranked/sortable grid instead of the raw autocomplete list. The ?query= URL param does not render results (the page shows "NO PART NUMBER CAPTURED" for any ?query=, even an exact MPN) — you must perform the WebForm postback:

  1. browse open https://www.questcomp.com/, set the header box: document.querySelector("#searchBoxHeader").value = "<pn>".
  2. Trigger the postback: eval(document.querySelector("a[id$=searchButtonHeader]").getAttribute("href")) (a WebForm_DoPostBackWithOptions targeting /searchresults.aspx), then browse wait.
  3. Harvest a[href*="/part/"] hrefs from the rendered grid. Sorting is via postback links lbPNSort (Part #) and lbQtySort (Qty); pagination is 10/page via postback (Results: 1 to 10 of N, page links 1/2/3…); there is an Email / Download (CSV) export and a "hide products with tariff" toggle. The "Exact match" and "In Stock" checkboxes filter the set. None of this is URL-addressable — prefer the Step 1 API unless you specifically need the grid features.

Site-Specific Gotchas

  • No parametric / descriptive search on the main site. searchresults.aspx and the autocomplete API only match part-number strings. Descriptive queries like "10uF tantalum capacitor" or "obsolete 74LS logic IC" return "NO PART NUMBER CAPTURED" / empty {"d":""} — this is expected, not a bug. Quest delegates spec/parametric search to a separate host: questcomp.componentsearchengine.com (a CIE/Component Search Engine instance, title "Quest Components Component Search"; whitelisted in the main site's CSP frame-src/connect-src). Route parametric queries there; note it is a different platform with its own extraction shape (out of scope for this skill, which covers the questcomp.com host).
  • ?query= in the URL is a decoy. GET /searchresults.aspx?query=SN74LS00N returns HTTP 200 but the results grid is empty ("NO PART NUMBER CAPTURED"); the query only pre-fills the search box. Results exist only after the __doPostBack. Don't parse the GET response for results — you'll get a false "not found" (classic broken-extraction trap). Use the Step 1 JSON API instead.
  • Always use www. questcomp.com → 301 → www.questcomp.com. /search/<term> → 301 → /search/<lowercased-term> (and is not the data path). ASP.NET backend (X-Powered-By: ASP.NET).
  • A single MPN detail page = many offers. offers.offerCount in JSON-LD is often 20–60+ (different manufacturers / date codes / packaging). lowPrice is the min unit price across ALL of them and ALL qty breaks — it is not tied to one manufacturer. Report manufacturer: null (reason "multiple_offers:<n>") unless offerCount == 1. Expand the offer grid only when a per-manufacturer breakdown is explicitly required.
  • unit_price has a Min Qty caveat. Prices are quantity-break tiered (e.g. 6+ 0.9000 / 21+ 0.5400 / 94+ 0.4200), and each offer has a Min Qty (often 6, 15, 25…). lowPrice may only be attainable at a high quantity. If a true unit-of-1 price matters, read the qty-break table on the detail page rather than trusting lowPrice as a 1-off price.
  • Zero-stock / quote-only parts are valid results, not errors. A part that exists but has no priced/in-stock offer (e.g. /part/4/sn74ls00n-00/382914398) renders JSON-LD with lowPrice: 0 and offerCount: 0, has no "parts available" total, and shows a Request-for-Quote (RFQ) / Quote Cart CTA instead of a price. Return unit_price: null (reason "rfq_only_no_priced_offer"), stock_qty: 0. The RFQ path is #quickOrderDetails / the Quote Cart — locate only, never submit.
  • Datasheet resolution is session-bound. getdatasheeturl needs the page's hfDsUser token (0;<GUID>;<IP>); a wrong/missing dsUser → HTTP 500. The two-step getdatasheetid(dsKeys) path in datasheet.js returns empty for these data-dsids — call getdatasheeturl directly with the raw data-dsid as dsID. Datasheets are hosted on 4donline.ihs.com (IHS/Accuris), not on questcomp.com.
  • Login is a public read is NOT gated. Price, stock, datasheet, and specs all render fully logged out (verified anonymously). Login is a header dropdown (#login-dp) posting to /index.aspx/verifycredentials; the account area /account/ is robots-disallowed. An anonymous agent needs no sign-in for any read field — sign-in only unlocks quoting/ordering/"my part number" mapping, which is out of scope.
  • robots.txt (https://www.questcomp.com/robots.txt) disallows /account/, /shopping/, /media/, /promotions/, /questdetails.aspx, /inventoryitems.aspx, /mfgstable.aspx, /inventorylist.aspx for all agents, and Disallow: / for dotbot. The paths this skill uses — /part/..., /searchresults.aspx, /baseform.aspx/searchpartsforautocomplete, /productcategorylisting.aspx/getdatasheeturl — are NOT disallowed. Do not touch inventoryitems.aspx/inventorylist.aspx/questdetails.aspx (disallowed and superseded by /part/ anyway). A Sitemap index (/sitemaps/sitemapindex.xml, ~44 shards × 25k URLs) enumerates every /part/ URL if you need bulk discovery. Yandex crawl-delay is 10s; keep requests polite (≤1 req/s).
  • "parts available" vs per-offer qty are different numbers. The header "N parts available" is the total across all offers; the Quick-Order box shows the primary (lowest-price in-stock) offer's qty (e.g. 170), and each grid row has its own avail qty (151, 19, 20…). Use the header total for stock_qty.
  • Egress note for sandboxed replay: these endpoints only respond from an allowed network path. In a locked-down sandbox, direct curl to questcomp.com fails (HTTP 000); issue the POSTs via fetch() inside a Browserbase page (browse eval) or via browse cloud fetch (GET-only, good for detail pages) so requests originate from the browser egress.

Expected Output

1. Exact lookup (in-stock, aggregated multi-offer part):

{
  "query": "SN74LS00N",
  "method": "api:searchpartsforautocomplete + fetch:/part detail JSON-LD",
  "source": "POST https://www.questcomp.com/baseform.aspx/searchpartsforautocomplete {\"pn\":\"SN74LS00N\"} -> GET https://www.questcomp.com/part/4/sn74ls00n/382914397",
  "results": [
    {
      "mpn": "SN74LS00N",
      "manufacturer": null,
      "description": "IC,LOGIC GATE,QUAD 2-INPUT NAND,LS-TTL,DIP,14PIN,PLASTIC",
      "unit_price": 0.2250,
      "currency": "USD",
      "stock_qty": 2515,
      "datasheet_url": "https://4donline.ihs.com/images/VipMasterIC/IC/MOTO/MOTOS12583/MOTOS12583-1.pdf?hkey=D9A213CC6FEE7D103EF6B88F2AEB20B8",
      "detail_url": "https://www.questcomp.com/part/4/sn74ls00n/382914397",
      "checked": "2026-08-07T18:48:00Z"
    }
  ],
  "note": "manufacturer=null: offerCount=27 (Motorola/Texas Instruments/ON Semiconductor...); unit_price is JSON-LD lowPrice (lowest across all offers & qty-breaks, Min Qty applies); stock_qty is total 'parts available'. Prices/stock/datasheet all public logged-out."
}

2. Keyword search by partial part number (family enumeration):

{
  "query": "74LS00",
  "method": "api:searchpartsforautocomplete (substring match, cap 16)",
  "source": "POST https://www.questcomp.com/baseform.aspx/searchpartsforautocomplete {\"pn\":\"74LS00\"}",
  "results": [
    {"mpn": "74LS00N", "manufacturer": null, "description": null, "unit_price": null, "currency": "USD", "stock_qty": null, "datasheet_url": null, "detail_url": "https://www.questcomp.com/part/4/74ls00n/70681577", "checked": "2026-08-07T18:48:00Z"},
    {"mpn": "74LS00D", "manufacturer": null, "description": null, "unit_price": null, "currency": "USD", "stock_qty": null, "datasheet_url": null, "detail_url": "https://www.questcomp.com/part/4/74ls00d/433525312", "checked": "2026-08-07T18:48:00Z"}
  ],
  "note": "Autocomplete returns MPN + IsStock + detail URL only (up to 16 substring matches). Fields left null are not-yet-fetched (reason 'not_expanded'); GET each detail_url to populate price/stock/description/datasheet. Site has no parametric search — a descriptive phrase would return empty (see shape 4)."
}

3. Edge case — part exists but zero-stock / quote-only / no priced offer:

{
  "query": "SN74LS00N-00",
  "method": "fetch:/part detail JSON-LD",
  "source": "GET https://www.questcomp.com/part/4/sn74ls00n-00/382914398",
  "results": [
    {
      "mpn": "SN74LS00N-00",
      "manufacturer": null,
      "description": null,
      "unit_price": null,
      "currency": "USD",
      "stock_qty": 0,
      "datasheet_url": null,
      "detail_url": "https://www.questcomp.com/part/4/sn74ls00n-00/382914398",
      "checked": "2026-08-07T18:52:00Z"
    }
  ],
  "note": "Valid part, not an error. JSON-LD offerCount=0, lowPrice=0 -> unit_price=null (reason 'rfq_only_no_priced_offer'), stock_qty=0. Page shows Request-for-Quote / Quote Cart CTA instead of a price; RFQ path located, not submitted (read-only). manufacturer=null (reason 'no_offer'). description=null (reason 'not_present_on_page')."
}

4. Edge case — query matches nothing (correct empty answer):

{
  "query": "10uF tantalum capacitor",
  "method": "api:searchpartsforautocomplete",
  "source": "POST https://www.questcomp.com/baseform.aspx/searchpartsforautocomplete {\"pn\":\"10uF tantalum capacitor\"}",
  "results": [],
  "note": "Empty is a correct answer, not an error. Response was {\"d\":\"\"} (32 bytes). questcomp.com only matches PART-NUMBER strings; multi-word descriptive/parametric phrases never match (searchresults.aspx shows 'NO PART NUMBER CAPTURED'). For spec/parametric discovery, route to the separate host questcomp.componentsearchengine.com. A single MPN-substring token (e.g. '10uF') WOULD return up to 16 MPN matches; the full phrase does not."
}

Field notes / reason flags (never infer a value):

  • manufacturer: null → "multiple_offers:<n>" (offerCount>1) or "no_offer" (offerCount=0).
  • unit_price: null → "rfq_only_no_priced_offer" or "not_expanded" (search row not yet fetched).
  • stock_qty: 0 when no priced/in-stock offer; null → "not_expanded".
  • datasheet_url: null → "datasheet_requires_session_dsuser" or "no_datasheet_on_page".
  • currency is always "USD" (single US locale).
  • A real "not found" is the 32-byte {"d":""} (or "NO PART NUMBER CAPTURED"); a broken extraction is parsing ?query='s GET HTML or the pre-postback grid and seeing zero /part/ links — always confirm via the JSON API before declaring "not found".