Alpaca Broker Account Onboarding

Alpaca Broker API — Account Onboarding & KYC

Create and manage end-user brokerage accounts under your firm. This is the first step of any Broker API integration: no funding, journaling, or trading can happen until an account reaches ACTIVE.

Read alpaca-broker-integration first for base URLs, auth, and conventions. This skill assumes Broker API + HTTP Basic auth.

Reference

• Guide: https://docs.alpaca.markets/docs/getting-started-with-broker-api, https://docs.alpaca.markets/docs/accounts
• API ref: https://docs.alpaca.markets/reference/createaccount
• Live schema: alpaca-docs MCP → get-endpoint title "Broker API" path /v1/accounts

1. Endpoints

2. Create-account request (POST /v1/accounts)

Four objects are required: contact, identity, disclosures, agreements. documents and trusted_contact are optional but usually needed for KYC.

{
  "contact": {
    "email_address": "jane@example.com",
    "phone_number": "+15555555555",
    "street_address": ["20 N San Mateo Dr"],
    "city": "San Mateo",
    "state": "CA",            // required if country / country_of_tax_residence is USA
    "postal_code": "94401",
    "country": "USA"          // ISO 3166-1 alpha-3
  },
  "identity": {
    "given_name": "Jane",
    "family_name": "Doe",
    "date_of_birth": "1990-01-01",
    "tax_id_type": "USA_SSN", // see enum below
    "tax_id": "666-55-4321",
    "country_of_tax_residence": "USA",
    "funding_source": ["employment_income"]
  },
  "disclosures": {
    "is_control_person": false,
    "is_affiliated_exchange_or_finra": false,
    "is_politically_exposed": false,
    "immediate_family_exposed": false
  },
  "agreements": [
    { "agreement": "customer_agreement", "signed_at": "2026-01-02T18:09:33Z", "ip_address": "185.13.21.99" }
  ],
  "documents": [ /* OwnerDocumentUploadRequest[] — see §4 */ ],
  "trusted_contact": { "given_name": "Jim", "family_name": "Doe", "email_address": "jim@example.com" }
}

Key field rules:

• contact.street_address is an array (max 3 lines). contact.state required when country/tax-residence is USA.
• identity.funding_source is an array; one+ of employment_income, investments, inheritance, business_income, savings, family.
• tax_id_type enum is large and country-specific: USA_SSN, USA_ITIN, IND_PAN, MEX_RFC, GBR_NINO, … plus generic NATIONAL_ID, PASSPORT, DRIVER_LICENSE, OTHER_GOV_ID, NOT_SPECIFIED. Query the spec for the full list rather than hardcoding.
• Optional top-level: account_type (trading|custodial|donor_advised|ira), account_sub_type (IRA: traditional|roth), enabled_assets (us_equity|us_option|crypto|ipo, default us_equity).
• Deprecated: investment_objective/investment_time_horizon/liquidity_needs/risk_tolerance moved from identity to top-level.

Responses: 200 → account object · 409 email already registered · 422 invalid value · 400 malformed body.

3. Agreements

Each entry: agreement (customer_agreement, account_agreement, margin_agreement, crypto_agreement, options_agreement), signed_at (RFC3339), ip_address (IPv4), optional revision. You must present the agreement text to the user and capture the real signing timestamp + IP — Alpaca treats these as the legal record. revision defaults to the currently-active revision if omitted.

4. Documents & W-8BEN

documents[] items: document_type + (content base64 or content_data).

{ "document_type": "identity_verification", "content": "<base64>", "mime_type": "image/jpeg", "document_sub_type": "passport" }

• document_type enum includes identity_verification, address_verification, date_of_birth_verification, tax_id_verification, w8ben, w9, cip_result, and more.
• mime_type: application/pdf, image/png, image/jpeg — plus application/json only for w8ben.
• W-8BEN shortcut (lesson): instead of generating a PDF, upload content_data as a structured W8benDocument JSON object (full_name, country_citizen, permanent_address_*, date_of_birth, ip_address, timestamp, signer_full_name, …) and Alpaca renders the official form for you. This is the clean way to satisfy the tax-form requirement for non-US persons programmatically.
• Doc size cap: 10 MB per file when using Alpaca's KYC-as-a-service; no cap if you run your own KYC.

5. Account status lifecycle

status (and crypto_status) use the AccountStatus enum:

Happy path: SUBMITTED → APPROVAL_PENDING → APPROVED → ACTIVE.

Lesson — gate every downstream op on ACTIVE. A 200 from POST /v1/accounts does not mean tradable. Subscribe to account-status SSE events (or poll GET /v1/accounts/{id}) and only enable funding/journals/trading once status == ACTIVE. Trying to journal or trade into a non-active account fails.

6. KYC results & CIP

• kyc_results on the account object carries reject/accept/indeterminate categories (KYCResultType values like IDENTITY_VERIFICATION, TAX_IDENTIFICATION, ADDRESS_VERIFICATION, WATCHLIST_HIT, COUNTRY_NOT_SUPPORTED, OTHER) plus additional_information. summary is pass/fail (internal only).
• If you run KYC yourself (or via Onfido/Trulioo/Veriff/etc.), submit results via POST /v1/accounts/{id}/cip with a CIPInfo body (provider_name, kyc, document, photo, identity, watchlist sub-results). Sub-check results are clear/consider.
• Minimum to open an individual account: verify name, date of birth, address, and identification number.
• WATCHLIST_HIT / COUNTRY_NOT_SUPPORTED require no user action — Alpaca handles them manually.

7. Integration guidance & lessons learned

1. Normalize inputs to canonical formats before sending. Country fields must be ISO 3166-1 alpha-3 (USA, PHL, …) — strip any UI decoration (flags/emoji, display names) and validate against GET /v1/country-info. Garbage in country/country_of_tax_residence is a common 422.
2. Capture real agreement metadata. signed_at and ip_address must reflect the actual user action, not server time / a placeholder.
3. Treat creation as async. Persist the returned account_id immediately, then drive UI off the status events, not the create response.
4. Guard against paper/test accounts in production code paths. If you run both sandbox and live, make sure live event handlers reject sandbox/paper account IDs rather than silently mutating real records.
5. Idempotency on submit. A 409 on duplicate email is your friend — look up the existing account rather than retrying creation. Store your local user↔account_id mapping before the network call so a timeout doesn't orphan an account.
6. Closing is your responsibility to sequence. Before POST .../actions/close, you must liquidate all positions and withdraw all cash. The account record is not deleted — it goes ACCOUNT_CLOSED.

Related skills: fund the account → alpaca-broker-funding-transfers; move cash in via the firm sweep → alpaca-broker-journals; trade → alpaca-broker-trading-orders; track status in real time → alpaca-broker-sse-events.