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This guide covers how Baselayer’s Lien Search product works: what it searches, how results are returned, and what the response contains. For background on lien types, UCC filings, and key terminology, see Liens, Judgments, and Public Records before reading this guide. For step-by-step API implementation, see Lien Search: API Quickstart.

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1. What Baselayer Searches

A Baselayer lien search retrieves public lien filings from Secretary of State (SoS) registries across the United States. Baselayer returns:
  • UCC filings (UCC-1, UCC-3, UCC-5)
  • Federal tax liens (IRS)
  • State tax liens
  • County and municipal tax liens
  • Judgment liens (where available)
  • Associated lien documents (PDFs), where available by state
Coverage and refresh rates vary by state. Contact your Baselayer representative for the current coverage map and data freshness details for states relevant to your use case.

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2. Execution Mode

Lien searches support both synchronous and asynchronous execution, controlled via the Prefer header or your API key’s default mode. For full details, see Synchronous & Asynchronous Request Execution. Lien-specific webhook events emitted during async execution:
Note: Ad-hoc (name-based) lien searches never emit webhooks. Use the synchronous response, or poll GET /lien_searches/{lien_search_request_id} when executing asynchronously.

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3. State Coverage Model

Lien filings follow the debtor’s state of formation under UCC rules. This means the domestic state - the state where the business is incorporated or formed - is where UCC liens are perfected and effective. By default, Baselayer searches only the domestic state. Omitting search_states from the request is the recommended approach for most customers. Every state searched incurs a direct data cost. Searching all foreign-registered states without reason adds unnecessary spend without meaningfully improving lien coverage. When to add additional states:
  • The business is incorporated in one state but operates primarily in another — in this case, search both the incorporation state and the state of the business’s submitted address.
  • Collateral is physically located in a specific non-domestic state (common in equipment financing or inventory-backed lending).
  • The product or customer base requires a more thorough analysis including lien searches in all registered states.
  • The product involves non-standard asset classes tied to a specific geography.
Note: Tax liens may occasionally appear in foreign-registered states when the business has tax obligations there - for example, sales tax, payroll tax, or franchise tax. These are typically smaller and lower risk than domestic tax liens, unless the business’s primary operations are outside its domestic state.
Why searching all 50 states is never the right choice A business name is not a unique identifier at the national level. The same name can belong to entirely unrelated, independently incorporated companies across different states. Searching all 50 states expands the pool of unrelated businesses whose filings will appear in your results, creating false positives that require manual review to dismiss. The domestic state (and, when warranted, additional foreign states with a specific rationale) is always the right scope. Broader is not better here.
Baselayer supports three request types for POST /lien_searches, depending on what identifiers you have available: Option 1: Using a business_id Use a business_id from a previous Baselayer Business Search. The search targets the business’s domestic state unless search_states is provided. Option 2: Using a business_search_id with optional additional_search_entities Use the id returned directly from a Business Search response. This variant also supports additional_search_entities, which allows you to search for linked individuals (officers, guarantors, beneficial owners) or alternate business names in the same API call. This is the most powerful request type and the recommended approach when you need lien coverage beyond the primary business entity. Option 3: Using a person_id Use a person_id from a previous Baselayer person record. When using this option, search_states is required. This is covered in detail in Lien Search for Individuals.

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5. Response Structure

The primary content of the API response is the filings array: one object per lien filing found. Top-level response fields:

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5.1 Search Entities

The search_entities array lists every entity included in the search, the primary business and any additional entities submitted via additional_search_entities. Each entry includes: The normalized_name is the name Baselayer actually used when querying each state’s registry. Reviewing it helps understand which name variants were matched, particularly for businesses with abbreviations, punctuation, or common alternate forms.

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5.2 Filing Object Fields

Each object in the filings array represents a single lien filing.

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5.3 Filing Type (filing_type)

The filing_type field is Baselayer’s normalized classification of each lien filing. It is consistent across all states and is the field to use for programmatic classification logic. Consensual liens (created by agreement between lender and borrower): Statutory liens (created by operation of law): Judicial liens (arising from court proceedings): Tax liens (filed by government authorities): Detecting tax liens: Any filing where filing_type starts with tax. is a government-originated tax lien. No keyword matching on raw registry strings is required. Detecting judicial liens: Any filing where filing_type starts with judicial. results from a court proceeding.

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5.4 Parties

The parties array lists all parties associated with a filing. Each party includes:

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5.5 Amendments

The amendments array contains a chronological record of all follow-on filings made against the original lien. Each amendment includes: Amendment filing_type values: Raw amendment codes from each state registry are normalized into this fourteen-value set at ingestion. Codes that cannot be mapped become unspecified. Reading the amendments array gives you the full lifecycle of a lien, but you do not need to parse it to determine whether the lien is open or closed. The top-level status field already incorporates amendment effects under the UCC §9-515 rollup rules: a termination amendment produces status: "terminated", a continuation filed within the statutory window keeps the filing active, and otherwise the lapse date decides active vs lapsed. Treat status as the authoritative open/closed signal and amendments[] as supporting evidence. A continuation confirms the secured party is actively maintaining the filing. collateral_amendment.remove or collateral_amendment.update entries may indicate restructuring or partial release of pledged assets and are worth reviewing in larger-ticket underwriting.

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5.6 Collateral Statements

The collateral_statements array contains textual descriptions of the assets covered by the lien, exactly as recorded in the state registry. Each entry includes: Collateral statements are particularly useful for determining the scope of a lien. A broad “all assets” description indicates a blanket lien; specific descriptions (equipment, vehicles, inventory) indicate a narrower security interest limited to particular asset categories.

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5.7 Match Level

The match_level field indicates how closely the filing’s debtor name matched the searched entity name. Possible values are EXACT, SIMILAR, and NO_MATCH. Baselayer applies a strict matching process, so all returned filings will carry an EXACT or SIMILAR match level.

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5.8 Document Availability

PDF documents are available for many filings at no additional cost, subject to state availability and filing date. To check availability: inspect document_filename on any filing object. A non-null value indicates a document is available. To retrieve the document:
This returns a 307 redirect to a signed URL for a consolidated PDF of all documents associated with that filing — configure your HTTP client to follow redirects. Not all states provide documents digitally; availability of historical filings (particularly pre-2010) varies.
Note: number_of_pages is descriptive metadata only. A filing can report a page count without having a retrievable document — document_filename being non-null is the only reliable signal that a download is available.

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6. Where to Go Next