Assignee

USPTO assignment API for patent assignment and ownership data

The Assignee API gives your software the same answer a patent paralegal spends an afternoon assembling: who owns a US patent on the public record, how ownership got there, and what still hangs on it. You send a patent number. You get back the current owner of record, every recorded conveyance in order with reel and frame, and flags for title gaps and unreleased security interests, as structured JSON your systems can store and compare.

9,567,890 10,890,123 9,890,123

What the Assignee assignment API returns

Raw USPTO assignment data is a list of separate recorded documents. Each one names an assignor, an assignee, a conveyance text, dates and a reel and frame. Nothing in that list tells you which document is the latest valid transfer, whether a name change connects two entities, or whether a security agreement was ever released. Developers who build on the raw feed end up writing that logic themselves, then maintaining it every time the source format or endpoint changes.

The Assignee API does the assembly first and returns the result. For each patent the response carries the owner of record, the chain of title from the inventors forward, the security interests matched to their releases, and a list of flags with the document that caused each one. Your docketing tool, data room or underwriting model reads one record instead of rebuilding history from fragments.

Trace ownership

Fields in every patent ownership response

  • Patent number, application number and title
  • Current owner of record, stated as one value at the top of the record
  • Every recorded conveyance in date order with assignor, assignee, conveyance type, execution date and recordation date
  • Reel and frame for each conveyance, so a reviewer can open the source document
  • Inventors named on the patent and whether a recorded assignment exists from each one
  • Security agreements paired with the releases that ended them, and any that remain open
  • Changes of name and mergers linked to the entity that holds the patent now
  • Title risk flags with a short code, a plain description and the document behind it

The same fields appear in the PDF and CSV report exports, so a record pulled through the API matches what a colleague sees in the web app.

What teams build on a patent assignment API

  • Docketing checks. Compare the owner your docket lists for each patent with the owner of record, and open a task wherever they differ.
  • Deal intake. Pull the chain of title for every patent on a seller's schedule the day the data room opens, before anyone reads a document. See patent due diligence.
  • Collateral review. Flag any patent in a borrowing base that already carries an open security interest, then hand the list to counsel for the UCC half of the search described in patent lien search.
  • Licensing programs. Confirm the licensor holds title to every patent on the schedule before the license goes out, see patent licensing.
  • Portfolio hygiene after an acquisition. Find every patent still recorded under a former company name.
  • Data products. Add an owner of record column to patent datasets used in analytics or valuation work, see patent valuation.

Assignee API compared with the official USPTO assignment data

USPTO assignment data services Scrapers of the USPTO search Assignee API
Cost No charge Pay per run, plus maintenance Included in Firm and Enterprise plans
What you receive Individual recorded documents Rows copied from the search page Assembled chain of title per patent
Owner of record computed No, you derive it No Yes
Liens matched to releases No No Yes
Title gap flags No No Yes
Name searches Capped result sets Capped by the source page Owner lists by company and corporate family
Breaks when USPTO changes tools You update your client Often We absorb the change
Same data in a web app for reviewers Separate USPTO search No Yes, with PDF and CSV export

The USPTO is the authoritative source and its data costs nothing, which makes it the right choice if you have engineers to build and maintain the ownership logic. The agency replaced its legacy assignment search tools with a single Assignment Search application in Assignment Center in October 2025, and integrations built on the older services had to follow. Scrapers copy whatever the search page shows, so they inherit its result caps and break when the page changes. Assignee is for teams that want the computed answer and a stable interface, and would rather spend engineering time on their own product.

How to start with the USPTO assignment API

  1. 1

    Run a free trace on the search above to see the record format for a patent you know.

  2. 2

    Create your account and choose the Firm plan, or Enterprise for dedicated API limits.

  3. 3

    Generate an API key in your account settings and keep it on your server, never in a browser.

  4. 4

    Request a patent by number and store the owner of record and the flags in your own system.

  5. 5

    Add the patents you care about to monitoring, so a newly recorded assignment or release reaches you without polling.

Who buys patent ownership data by API

  • IP departments at companies with thousands of patents across subsidiaries, see intellectual property management software
  • Law firms running title checks for many clients at once
  • Patent lenders and venture debt funds screening collateral
  • Brokers and buyers who screen large lists of patents for sale, see sell my patent
  • Legal tech and data companies that resell or enrich patent records
  • Analytics teams who need ownership by company, see patent assignee search

USPTO assignment API pricing

API access is included in the Firm plan at $299 a month billed yearly, or $599 billed monthly, with 600 chain of title reports a month, 10 seats and 5,000 patents in monitoring. Enterprise starts at $1,499 a month and adds dedicated API limits, SSO with SAML, an audit log and a service level agreement. Every plan is listed on the pricing page.

Questions about the USPTO assignment API

Does the USPTO have an API for patent assignments?

Yes. The USPTO publishes patent assignment data through its developer services and bulk data files, at no charge. It returns the recorded documents one by one, so deciding who owns the patent today, matching liens to releases and spotting gaps is left to your own code.

How do I get patent assignment data in bulk?

For a few patents, a search tool is enough. For hundreds or thousands, use an API or bulk files. The USPTO bulk files contain every recorded assignment but need parsing and joining. The Assignee API and Excel export return the assembled ownership record per patent, ready for a spreadsheet or a database.

How do I find the current owner of a patent programmatically?

Request the patent's recorded assignments, order them by date, and follow each assignee to the next assignor, accounting for name changes and mergers. The last valid transfer gives the owner of record. The Assignee API returns that owner directly, along with the chain that supports it.

Is the owner of record the legal owner of the patent?

Not always. The owner of record is what the USPTO assignment records show. An unrecorded assignment can still be valid between the parties, so a signed transfer may exist that the record does not show. For a closing or a lawsuit, counsel confirms title with the documents.

Which plan includes API access?

API access is part of the Firm plan and of Enterprise, which adds dedicated limits for high volumes. The Analyst and Professional plans use the web app with PDF and CSV exports.

Can I test the data before buying API access?

Yes. The search on this page runs a real trace on any US patent number without an account, showing the owner of record and the first links of the chain of title. The API returns the same record in structured form.

For the background on the source records, read USPTO assignment database and patent chain of title.

Put patent ownership data into your own systems

Trace one patent now, then connect the API on the Firm plan when the record looks right.

Trace ownership