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UCOlock — secure traceability warehouse
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Chain of custody · used cooking oil

Every sale, traced back to the sites it was collected from.

UCOlock holds the collection, purchase and sale records of a used cooking oil supply chain and links each sale to the purchases that filled it, and each purchase to the collections behind it. An auditor reads the whole chain, from delivery back to collection site: the proof an LCFS or RFS compliance review asks for.

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Accounts are invite-only. Auditors do not need one.

Collector site lists are shown only to an approved auditor.

Chain-of-custody reportSample data · identifiers are placeholders

Sale S-0412

Delivered 2026-03-14 · Buyer C-07 · 42,000 lbs

Purchases listed for this load

PurchaseVendorShippedlbs
P-2287Vendor V-032026-03-0218,500
P-2291Vendor V-112026-03-0516,240
P-2294Vendor V-032026-03-097,260
Total allocated42,000

The site list is disclosed to the auditor only. It is never shown to the broker or the buyer.

01

How the record is built

Four parties, one ledger. Each party files only what it is responsible for, and allocation joins those files into a chain that runs from a buyer's delivery back to a collection site.

Chain of custody from collection sites to buyerFour stages: a locked list of restaurant collection sites, the collector's monthly log, the broker's purchases and a sale matched to two of them by trade number, and the buyer, who files nothing. A dashed auditor line reads back across all four stages to the locked site list.AuditorReads the whole chainback to the collectionsites through one link,valid for 30 days.Collection sitesa collector's client list2,400 lbs1,150 lbs3,020 lbs880 lbsHidden from the broker and the buyer.Disclosed only in the auditor’s report.collectionsCollectorvendor · logs every pickupCollections log · March03 Mar2,400 lbs11 Mar1,150 lbs19 Mar3,020 lbsSource directory and monthly log,from the Excel template. A brokermay file for a collector only withthe collector’s recorded consent.purchasesBrokerbuys from collectors, sells to buyersPurchases, by trade numberLot 1 · shipped 03 Mar8,000 lbs · all allocatedLot 2 · shipped 11 Mar6,000 lbs · 4,000 allocatedLot 3 · shipped 22 Mar7,000 lbs · in inventorySale S-11812,000 lbsdelivered 18 Mar8,000 from Lot 14,000 from Lot 2Each sale is matched to purchasesunder its own trade number, orlisted by the broker for its load,such as a railcar of several trucks.The auditor reads the ledger rows.saleBuyerbiofuel producerSale S-118 · 12,000 lbsdelivered 18 MarClaims LCFS and RFS creditsFiles nothing; the broker records thesale to it. Its compliance team mustshow the oil is genuine waste oil.

One sale, traced. Sale S-118 was made up of two purchases the broker listed for it by trade number; the third is still in inventory. The auditor's report follows each of those purchases back to the collector's log, whose pickups are assigned to the collector's loads oldest first, and to the sites in it. The broker and the buyer see the purchases and the sale; the site list is never shown to them.

Records as filed: the collector’s log, the broker’s purchases and sales
The auditor’s read access, by approved link
Disclosed only inside the auditor’s report

  1. 1

    Collectors record their collections

    Each collector keeps a directory of the restaurants and sites it collects from, and files a monthly collections log against it. Both arrive as Excel templates through the collector's own portal.

  2. 2

    The broker records purchases and sales

    The broker files its own monthly template: purchases received from collectors, with the date each load shipped, and sales delivered to buyers. A broker may file a collector's monthly log only with that collector's recorded consent.

  3. 3

    Trade numbers link each sale to its purchases

    A sale is matched to the purchases recorded under its own trade number, or that the broker lists as part of its load, such as a railcar packed from several trucks. Each collector's pickups are assigned to the loads it sold, oldest first. The result is a ledger row for every pairing, so a sale resolves to purchases, purchases to collectors, and collectors to sites.

  4. 4

    An auditor reads the whole chain

    An auditor names the buyer and the period under review through a public form. The broker approves or denies the request; once approved, the auditor receives a link to the complete report, valid for 30 days. No auditor account is created.

02

Who sees what

A collector's restaurant list is never shown to the broker or the buyer. It is disclosed to an auditor, inside a complete chain-of-custody report, and nowhere else.

Each role signs in to its own portal and reads only its own records. The site list is the collector's client list, and keeping it confidential is the condition on which collectors can file at all.

Who can read each record

  • Collector’s source directory

    the restaurants and sites it collects from

    Collector
    own
    Broker
    no
    Buyer
    no
    Auditor
    in report

  • Collector’s collections log

    site, date and weight per pickup

    Collector
    own
    Broker
    no
    Buyer
    no
    Auditor
    in report

  • Broker’s purchases

    from collectors, with the date each load shipped

    Collector
    own loads
    Broker
    all
    Buyer
    no
    Auditor
    in report

  • Pickup coverage

    which pickups make up each load the collector sold

    Collector
    own loads
    Broker
    counts per collector
    Buyer
    complete or not, per delivery
    Auditor
    in report

  • Broker’s sales

    deliveries to buyers

    Collector
    no
    Broker
    all
    Buyer
    own deliveries
    Auditor
    in report

  • Allocation ledger

    which purchases filled each sale

    Collector
    no
    Broker
    all
    Buyer
    traced weight, per delivery
    Auditor
    in report

  • Audit requests

    who asked to review which buyer and period

    Collector
    no
    Broker
    all, to approve or deny
    Buyer
    own
    Auditor
    the approved request

Enforced by row-level policies in the database, not by what a screen chooses to show. The auditor reads through a time-limited link, never through an account.

03

How the record is kept

Imports that cannot half-succeed
A monthly file with a single bad row is rejected whole and every error is reported, so a month can never be half-imported. Ambiguous dates are refused rather than guessed.
Shortfalls are reported, not hidden
If the purchases matched to a sale do not cover it, the report shows the untraced weight beside the traced weight.
Consent, on the record
Only a collector can record consent for the broker to file on its behalf, and each such filing is pinned to the consent that authorised it.
One database per broker
Each broker's deployment runs on its own subdomain with its own isolated database. Nothing is pooled.
Neutral custody
Records are held by a third party, outside any one party's spreadsheets, and retained for regulatory review.

Access

Two ways in, and no sign-up.

Invited users sign in. Auditors ask for a link. Nobody else has a route to the records, which is the point of keeping them here.

Collectors, brokers and buyers

Sign in once the broker has added your email to the directory. Each role opens in its own portal.

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Auditors

Reviewing an LCFS or RFS claim? Request the chain of custody.

  1. 1Request. Name the buyer and the period.
  2. 2The broker approves or denies. The request appears in the broker's portal.
  3. 3The report opens. A link valid for 30 days.

Public form. No sign-in required.

Request audit access