> ## Documentation Index > Fetch the complete documentation index at: https://developers.securitize.io/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > SecId API: use the sandbox base URL https://partners-api.sandbox.securitize.io/investors/v1/onboarding-reliance unless the user explicitly provides production access. Authenticate with OAuth 2.0 client credentials: POST https://partners-api.sandbox.securitize.io/oauth2/token (form fields grant_type=client_credentials, client_id, client_secret, read from environment variables), cache the bearer token for its expires_in (7200 s) and send it as Authorization: Bearer on every call; never print or log the secret or the token. > Nothing is verified until POST /investors/{investorId}/verification/submit. An individual: create, upload one identity document, submit. A company: create, add its people as key parties (at least one with isBeneficialOwner: true), upload their documents, submit. > Branch on the HTTP status and the error `code`, never on `message`. A body without `code` comes from the gateway: on a 401 get a new token and send the request again; a 403 means the account is not enabled for this API. > SecId API addresses: send address.state only when that address's countryCode is US, as the 2-letter state code (NY); omit it for any other country, also when the user has a province or region. Otherwise the call answers 400 validation_error on address.state. > SecId API individuals in the US: taxId is the person's Social Security number, and it is checked against the name and residential address sent; send them as registered. A mismatch can move the investor to manual-review instead of verified. Sandbox does not run the check. > Creates are safe to repeat with the same body: after a timeout or a 502, send the identical create again. Document uploads are not: each call stores a new document, so only re-send a document after a 502. > Poll GET /investors/{investorId} about every 30 seconds, then back off; treat any status you do not recognise as not verified. In sandbox, the webhook investor.kyc.updated also announces every status change, and investor.suitability.updated / investor.dlt_test.updated every change of the suitability and DLT test verificationStatus: verify the signature, deduplicate on sourceEventId and confirm with the matching GET before acting. Token whitelisting is asynchronous too: poll GET /investors/{investorId}/wallets/whitelist until the status leaves processing. > SecId API tax forms: POST /investors/{investorId}/tax-forms takes multipart/form-data (parts file, formType, signatureDate); never base64 or JSON. Let the HTTP client set content-type with the boundary. At any point of the verification, before or after the investor is verified, only for investors you created (201), one PDF up to 10 MB per call; each upload replaces the form on file, so after a 502 send the same request again. A W-9 can instead go as JSON fields to POST /investors/{investorId}/tax-forms/w9 (TIN as 9 digits, SSN or EIN): it does not replace a form on file (409 tax_form_already_active, details.activeTaxForm), and it requires a certification object (certifiedAt, signatureName, subjectToBackupWithholding false, isUSPerson true, certificationTextVersion w9-sm-2026-10): the investor certifies in your flow on the text published at /secid-api/tax-forms#the-certification, shown without changes; subjectToBackupWithholding true answers 422 business_rule_violation (details.reason backup_withholding_not_supported). Unlike creates, a repeat after success answers 409 tax_form_already_active, not 201: when details.activeTaxForm.formType is W-9, treat it as on file. > Use synthetic test data in sandbox (@test.invalid emails, fresh ids each run). Never send more than one DLT test attempt per test investor unless the user asks: three failed attempts lock the test permanently. > The complete contract, with every field, response and error, is the OpenAPI file of the API reference; the Errors page says what to do for each code. > CET Underlying API: a WebSocket at wss://partners-rt-gw.sandbox.securitize.io/v1/market-maker/stream (TLS only; ws:// hangs with no answer). Sign hello, place_order, cancel_order and submit_crypto_funding with the user's Ed25519 key, read from an environment variable or secrets store; never print or log it. Sign timestamp + "." + type + "." + the exact payload string you send: serialise the payload once and embed that same string in the frame. > CET Underlying API: send a unique requestId of at most 32 characters (a UUID without hyphens) on every message and match replies on it; frames without a requestId are pushes. Every amount is a decimal string, never a JSON number; compare amounts as decimals. Branch on the error code, never on message. > CET Underlying API: an ack to place_order means taken, not filled. externalRef is the idempotency key; after an ack with status UNKNOWN or an UPSTREAM_UNAVAILABLE error, call get_order by externalRef before resending. Updates are delivered at most once: after any reconnect, read working orders back with get_order. Every order is placed by quantity. A buy must be a LIMIT order: quantity × limitPrice plus fees is held against your own available cash (get_cash_balance_v2), and a buy it does not cover, a MARKET buy or a notional order is refused (INVALID_ORDER). A sell must be placed by quantity, after its CETs reach the redemption wallet, or it is refused. mint_updated and burn_updated push mints and burns once they are on chain; after a gap, read them with get_mints and get_burns. The complete contract is the AsyncAPI file of the API reference. > Stocks API (Beta): documented ahead of its release through the partner gateway; paths, fields and errors can change. Base URL https://partners-api.sandbox.securitize.io/stocks/v1. Send x-api-key on every call and investorId on every call about an investor. Read the key from an environment variable; never print or log it, and never call the API from frontend code. > Stocks API: an investor can trade only once the SecId API shows them verified, with verified suitability (and a passed DLT test in the EEA), and once their wallet on the stock's chain is linked with their signature of the agreement message, signed verbatim. There is no whitelisting call: the first trade whitelists the wallet. > Stocks API: orders are fill or kill. GET /stocks/realtime-price, prepare within about 20 seconds (signedPrice), have the investor's wallet sign the returned transaction unchanged and sign-only (never send it), then submit it once with POST /stocks/execute-signed-transaction within 120 seconds. Amounts are raw base units as strings; USDC has 6 decimals. The outcome is on chain: follow transactionHash. > Stocks API: production access requires a UI audit by Securitize Compliance of the live screens: the disclosures and the market data shown, the NBBO included. > Corporate Actions API (Beta, 0.x): in development and subject to change; paths, fields, enumerations and event names can change before 1.0.0. Base URL https://partners-api.sandbox.securitize.io/corporate-actions/v1. Get a bearer token with OAuth 2.0 client credentials at POST https://partners-api.sandbox.securitize.io/oauth2/token (no scope, 2 hours), cache it, and send Authorization: Bearer on every call. Read the client id, secret and the webhook signing secret from environment variables; never print or log them, and never call the API from frontend code. > Corporate Actions API: webhooks arrive signed with the Standard Webhooks scheme under the svix-id, svix-timestamp and svix-signature headers (HMAC-SHA256 over id.timestamp.raw body, base64, v1 prefix; the secret is base64 after whsec_). Verify before parsing, reject a timestamp more than 5 minutes off, answer 2xx within 10 seconds. Delivery is at least once and can be out of order: deduplicate on sourceEventId, keep the highest version per object (objectId), order by sequence per stream.id, and replace the object with data (never merge). > Corporate Actions API: treat an unknown caType, reasonCode, eventType or enum value as informational, never as an error. A restriction ends only with ca.restriction.removed; expectedEnd is informational. marketStatus UNAVAILABLE means do not trade; the reason field carries a restriction reasonCode or a market reason such as PRE_MARKET. GET /tokens?status= filters by marketStatus (OPEN, CLOSED, UNAVAILABLE), not by the token's ACTIVE status. > Corporate Actions API: the event routes are at https://partners-api.sandbox.securitize.io/webhooks/v1 (not under /corporate-actions/v1) and cover every webhook family sent to the partner; filter with eventTypes=ca.* for corporate actions only. After an outage call POST /events/recover with since at the start of the outage (resends failed deliveries only), or page GET /events?since= (newest first, iterator paging, 90 days), then read state with GET /tokens/{tokenId}/status and GET /corporate-actions/{sourceCaId}. In sandbox, POST /sandbox/events with a scenario and one of your tokenIds publishes a scripted sequence at once; order the events by sequence, not by arrival. > Investor Activity API: base URL https://partners-api.sandbox.securitize.io/v1. Authentication is OAuth 2.0 client credentials only (no API key): POST https://partners-api.sandbox.securitize.io/oauth2/token (no scope, 2 hours), cache the token, and send Authorization: Bearer on every call. The token identifies the investor account; there is no investor id to pass. Read the client id, secret and the webhook signing secret from environment variables; never print or log them, and never call the API from frontend code. > Investor Activity API: every amount is an integer string in base units with a sibling decimals (human = amount / 10^decimals); parse with BigInt or a decimal type, never a float. Cash amounts (deposits, confirmations, payouts) are in the minor units of currencyId (1 = USD, decimals 2); token amounts (transactions, mintings, holdings) in the token's base units. Never add cash to tokens. > Investor Activity API: reconcile a subscription by grouping GET /deposits?tokenId= on tokenIssuanceId and matching the transaction in GET /transactions?tokenId= with the same tokenIssuanceId (null on a deposit means not issued yet; null on a transaction means not an issuance). Each issuance has a deposit movement (cash in) and a liquidation movement (that cash applied to the tokens) for the same amount: count the cash once, by direction=deposit, never by adding every movement. Page with offset and limit (max 100) until offset + meta.length reaches meta.total; there is no tokenIssuanceId filter. Reconcile a redemption by txHash (transfer, investor.redemption.pending, payout sourceTransaction) and by the redemption's data.id across pending, confirmed, payout.initiated and payout.completed. > Investor Activity API: webhooks arrive signed with the Standard Webhooks scheme under the svix-id, svix-timestamp and svix-signature headers (HMAC-SHA256 over id.timestamp.raw body, base64, v1 prefix; the secret is base64 after whsec_). Verify before parsing, reject a timestamp more than 5 minutes off, answer 2xx within 15 seconds. The body is {eventType, eventId, timestamp, data}: deduplicate on eventId (not svix-id), upsert by data.id, never move a record back to an earlier step, and treat an unknown eventType, processType or paymentMethod as informational. In webhooks a field with no value is absent; in endpoint answers it is null. After an outage page GET /webhook-events (newest first, iterator paging, optional eventType) back to the start of the outage. > SecId hosted onboarding: instead of the API, a partner can send an investor to https://stocks.securitize.io/partners?tokenId=&partnerUrl= (tokenAddress may replace tokenId; partnerUrl must be an absolute https URL, URL-encoded). Securitize runs identity verification, the investment profile and the wallet there. Nothing is appended to partnerUrl on return: check the wallet on chain before trading (Beta on Solana). # Send an investor's W-9 as data > Sends Securitize the fields of the W-9 an investor completed with you, as JSON, instead of a signed PDF, together with the investor's certification. Securitize puts the form on file for the investor, recorded as sent by you, and generates its PDF from these fields. For a US person, individual or entity: `formClassification` says which. The form can be sent at any point of the investor's verification, before or after it is `verified`. **The investor certifies the W-9 in your flow before you send it** (Part II, under penalties of perjury), on the certification text Securitize publishes in [Send a tax form](/secid-api/tax-forms#the-certification). `certification` records it: when the investor agreed, the name they signed with, their answers, and the version of the text they were shown. **Checks, in order** — each one stops the request, and nothing is kept: 1. the body is JSON (`content-type: application/json`) — else `415 mime_not_supported`; 2. every field, `certification` included, is valid — else `400 validation_error`, with `details` naming each field; 3. the investor resolves in your account — else `404 investor_not_found`; 4. you lead the investor's verification — else `409 investor_not_owned`; 5. the investor is not subject to backup withholding — else `422 business_rule_violation`, with `details.reason` `backup_withholding_not_supported`; 6. the investor has no tax form in force (valid, or pending review; an expired or rejected form does not count) — else `409 tax_form_already_active`, with `details.activeTaxForm` naming it. **A W-9 sent as data does not replace a form on file.** To correct or replace it, contact Securitize support with its `taxFormId`. The answer is a receipt: there is no call to read or list an investor's tax forms. ## OpenAPI ````yaml /secid-api/openapi.yaml post /investors/{investorId}/tax-forms/w9 openapi: 3.1.0 info: title: SecId API version: 1.0.0 description: > Onboard investors you have already KYC'd. Securitize accepts your identity verification instead of repeating it, and runs sanctions and PEP screening on top; a screening flag is reviewed by Securitize compliance, not rejected automatically. Both journeys follow the same steps: create the investor (an individual, or a company with the people and companies it is verified through, its key parties), upload their documents, submit, and poll for the verdict. Every path that names an investor takes the `investorId` Securitize returns, not your own id; `GET /investors?externalInvestorId=…` finds it by yours. The guides on the developer portal explain the flow, the states and the error handling in depth. servers: - url: >- https://partners-api.sandbox.securitize.io/investors/v1/onboarding-reliance description: Sandbox security: - OAuth2: [] tags: - name: Authentication description: > Exchange your client id and secret for the bearer token every other operation takes. - name: Individuals description: > Create and correct a natural person you are onboarding. Nothing is under review until you submit the investor. - name: Entities description: > Create and correct the company being onboarded. A company is never screened on its own: it is verified through its key parties once you submit it. - name: Key parties description: > The natural persons (beneficial owners, shareholders, signers) and the companies (corporate shareholders) an entity is verified through. People are screened; companies are recorded and reviewed by Securitize compliance. - name: Documents description: > Identity documents for an individual investor or a person key party; company documents for a company key party or for the entity itself. One document per call, base64 inside JSON. Documents never start a verification. - name: Verification description: >- Hand an investor to verification. For an entity, with all of its key parties in one call. - name: Lookup description: > Read an investor's status and data back, and recover an `investorId` you no longer have. - name: Wallets description: > Register the blockchain addresses an investor holds, and list the ones you registered. You vouch that the investor controls each address; registering alone does not let a wallet receive tokens. - name: Suitability and DLT test description: > Send the investor's suitability profile and, for investors in the European Economic Area, their attempts at the DLT knowledge test. A verified suitability is what token whitelisting requires. An individual can send the compact suitability instead: the part that a Securitize Markets brokerage account for stocks and '40 Act funds requires. - name: Token whitelisting description: > Whitelist an investor's EVM wallet on a token enabled for your account, so it can receive and hold that token, and follow its status. - name: Tax forms description: > Send an investor's tax form, at any point of the verification, so it is on file for the withholding on the investor's distributions: the W-9, W-8BEN or W-8BEN-E the investor signed, as a PDF in `multipart/form-data`, or the fields of a W-9 as JSON. - name: Webhooks description: > What Securitize POSTs to the endpoint your Securitize contact registered for you: one event per request, signed with your endpoint's secret. Available in sandbox. paths: /investors/{investorId}/tax-forms/w9: post: tags: - Tax forms summary: Send an investor's W-9 as data description: > Sends Securitize the fields of the W-9 an investor completed with you, as JSON, instead of a signed PDF, together with the investor's certification. Securitize puts the form on file for the investor, recorded as sent by you, and generates its PDF from these fields. For a US person, individual or entity: `formClassification` says which. The form can be sent at any point of the investor's verification, before or after it is `verified`. **The investor certifies the W-9 in your flow before you send it** (Part II, under penalties of perjury), on the certification text Securitize publishes in [Send a tax form](/secid-api/tax-forms#the-certification). `certification` records it: when the investor agreed, the name they signed with, their answers, and the version of the text they were shown. **Checks, in order** — each one stops the request, and nothing is kept: 1. the body is JSON (`content-type: application/json`) — else `415 mime_not_supported`; 2. every field, `certification` included, is valid — else `400 validation_error`, with `details` naming each field; 3. the investor resolves in your account — else `404 investor_not_found`; 4. you lead the investor's verification — else `409 investor_not_owned`; 5. the investor is not subject to backup withholding — else `422 business_rule_violation`, with `details.reason` `backup_withholding_not_supported`; 6. the investor has no tax form in force (valid, or pending review; an expired or rejected form does not count) — else `409 tax_form_already_active`, with `details.activeTaxForm` naming it. **A W-9 sent as data does not replace a form on file.** To correct or replace it, contact Securitize support with its `taxFormId`. The answer is a receipt: there is no call to read or list an investor's tax forms. operationId: submitW9 parameters: - $ref: '#/components/parameters/InvestorId' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/W9Data' examples: individual: summary: Individual, with an SSN value: formInvestorName: Jane Test address1: 1007 Liberty Street address2: Apt 2 city: Meadville region: PA postalCode: '16335' country: US formClassification: INDIVIDUAL taxPayerIdType: SSN taxPayerIdNumber: '123456789' taxCountry: US certification: certifiedAt: '2026-10-28T15:28:40Z' signatureName: Jane Test subjectToBackupWithholding: false isUSPerson: true certificationTextVersion: w9-sm-2026-10 entity: summary: LLC taxed as a C corporation, with an EIN and exemption codes value: formInvestorName: Test Holdings LLC businessName: Test Trading address1: 500 Market Street city: Philadelphia region: PA postalCode: '19106' country: US formClassification: LLC-C-CORPORATION taxPayerIdType: EIN taxPayerIdNumber: '987654321' exemptPayeeCodes: - 5 exemptFATCAReportingCodes: - A taxCountry: US certification: certifiedAt: '2026-10-28T11:28:40-04:00' signatureName: John Test subjectToBackupWithholding: false isUSPerson: true certificationTextVersion: w9-sm-2026-10 responses: '201': description: The W-9 is on file for the investor. content: application/json: schema: $ref: '#/components/schemas/W9Receipt' examples: w9: summary: W-9 received value: taxFormId: 5c2fe256-5474-4f5f-8d02-595b058ae698 formType: W-9 submittedAt: '2026-10-22T17:57:47.187Z' '400': description: > `validation_error` — a field is missing or invalid. `details` names every one (`[{ field, message }]`), so fix them together and send the form again; nothing was kept. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - validation_error examples: tinType: summary: A TIN type a W-9 does not take value: statusCode: 400 code: validation_error message: Validation failed details: - field: taxPayerIdType message: >- taxPayerIdType must be one of the following values: SSN, EIN correlationId: partners-api-47d3a9c5-3484-421f-abe6-44ee458d8cb6 tinNumber: summary: A TIN with dashes value: statusCode: 400 code: validation_error message: Validation failed details: - field: taxPayerIdNumber message: >- taxPayerIdNumber must be exactly 9 digits, without dashes correlationId: partners-api-0ec16ecb-2a66-48b5-b3c4-151a39b610a7 einRequired: summary: An SSN for a corporation value: statusCode: 400 code: validation_error message: Validation failed details: - field: taxPayerIdType message: >- taxPayerIdType must be EIN for formClassification C-CORPORATION correlationId: partners-api-c0b8c8a8-df49-441f-b748-85d04d4b4980 exemptionCodes: summary: Two exempt payee codes value: statusCode: 400 code: validation_error message: Validation failed details: - field: exemptPayeeCodes message: exemptPayeeCodes takes at most one code correlationId: partners-api-da71f0a1-8791-410e-9aab-a461e91bdf33 certificationMissing: summary: No certification value: statusCode: 400 code: validation_error message: Validation failed details: - field: certification message: certification must be an object correlationId: partners-api-6f0d2b8e-1c4a-4e57-9a3b-7d82c5e1f094 certifiedInTheFuture: summary: A certification dated in the future value: statusCode: 400 code: validation_error message: Validation failed details: - field: certification.certifiedAt message: certifiedAt must not be in the future correlationId: partners-api-b4e81c27-0d3f-4a96-8e15-c9a7f2d63b80 '401': $ref: '#/components/responses/GatewayUnauthorized' '403': $ref: '#/components/responses/GatewayForbidden' '404': $ref: '#/components/responses/InvestorNotFound' '409': description: > - `investor_not_owned` — another party leads this investor's verification; its tax forms are not yours to send. - `tax_form_already_active` — the investor already has a tax form in force, and a W-9 sent as data does not replace it. `details.activeTaxForm` names it (`taxFormId`, `formType`) when it can be read. A `formType` of `W-9` on an investor you sent no other W-9 is your earlier one: it is on file, keep its `taxFormId`. For any other form, or no `details`, contact Securitize support to correct or replace it. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - investor_not_owned - tax_form_already_active examples: alreadyActive: summary: The investor already has a W-8BEN on file value: statusCode: 409 code: tax_form_already_active message: The investor already has an active tax form details: activeTaxForm: taxFormId: db368cda-c9c4-40ab-9d70-b511fe4a6686 formType: W-8BEN correlationId: partners-api-3cbd46e6-cce2-4caf-b4b5-ab8738084bd4 notOwned: $ref: '#/components/examples/InvestorNotOwned' '415': $ref: '#/components/responses/ContentTypeNotJson' '422': description: > `business_rule_violation` with `details.reason` `backup_withholding_not_supported` — the investor certified they are subject to backup withholding (`certification.subjectToBackupWithholding: true`). Such a W-9 cannot be sent as data; nothing was kept. Contact Securitize support for this investor. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - business_rule_violation examples: backupWithholding: summary: An investor subject to backup withholding value: statusCode: 422 code: business_rule_violation message: A W-9 subject to backup withholding cannot be sent as data details: reason: backup_withholding_not_supported correlationId: partners-api-8c3a5f19-62d7-4b0e-a4c1-e95d07b2f6a3 '500': $ref: '#/components/responses/InternalError' '502': description: > `tax_form_registration_failed` — the form may or may not be on file. Send the same request again: a `201` puts it on file, and a `409 tax_form_already_active` naming a `W-9` means the first attempt is on file. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - tax_form_registration_failed examples: registrationFailed: summary: The form could not be put on file value: statusCode: 502 code: tax_form_registration_failed message: The tax form could not be registered, retry later correlationId: partners-api-1c7e4b2a-9d3f-4a68-b5e0-2f8c6d1a7e93 components: parameters: InvestorId: name: investorId in: path required: true description: > The `investorId` Securitize returned when you created the investor. Not your `externalInvestorId`. schema: $ref: '#/components/schemas/SecuritizeId' schemas: W9Data: type: object description: >- The fields of the W-9, as the investor completed it. Securitize generates the form's PDF from them, with the line 1 name as the signature and the day Securitize receives the form as its date. Text fields are trimmed; unknown fields are ignored. required: - formInvestorName - address1 - city - postalCode - country - formClassification - taxPayerIdType - taxPayerIdNumber - taxCountry - certification properties: formInvestorName: type: string minLength: 1 maxLength: 100 description: 'Line 1: the name as shown on the investor''s income tax return.' examples: - Jane Test businessName: type: string maxLength: 100 description: >- Line 2: the business or disregarded entity name, when different from line 1. address1: type: string minLength: 1 maxLength: 100 description: 'Line 5: number, street, and apartment or suite.' address2: type: string maxLength: 100 description: A second address line. city: type: string minLength: 1 maxLength: 60 region: type: string maxLength: 60 description: >- The state for a US address. It may be omitted for an address abroad that has none. postalCode: type: string minLength: 1 maxLength: 20 country: type: string description: The address's country, ISO 3166-1 alpha-2. Case-insensitive. examples: - US formClassification: type: string description: >- Line 3a, the federal tax classification. `INDIVIDUAL`, `SOLE` (sole proprietor) and `SINGLE` (single-member LLC) mark the first box; `C-CORPORATION`, `S-CORPORATION`, `PARTNERSHIP` and `TRUST` (trust or estate) their own box; `LLC-C-CORPORATION`, `LLC-S-CORPORATION` and `LLC-PARTNERSHIP` mark the LLC box with that tax classification. enum: - INDIVIDUAL - SOLE - SINGLE - C-CORPORATION - S-CORPORATION - PARTNERSHIP - TRUST - LLC-C-CORPORATION - LLC-S-CORPORATION - LLC-PARTNERSHIP taxPayerIdType: type: string description: >- Part I: `SSN` for a social security number or an ITIN, `EIN` for an employer identification number. A corporation, a partnership or an LLC taxed as either (`C-CORPORATION`, `S-CORPORATION`, `PARTNERSHIP`, `LLC-*`) sends `EIN`. enum: - SSN - EIN taxPayerIdNumber: type: string pattern: ^\d{9}$ description: The SSN, ITIN or EIN, exactly 9 digits, without dashes. examples: - '123456789' exemptPayeeCodes: type: array maxItems: 1 description: >- Line 4, the exempt payee code, if any applies. At most one code, an integer from 1 to 13. Omit it, or send an empty list, when none applies. items: type: integer minimum: 1 maximum: 13 exemptFATCAReportingCodes: type: array maxItems: 1 description: >- Line 4, the exemption from FATCA reporting code, if any applies. At most one code, a letter from A to M. Omit it, or send an empty list, when none applies. items: type: string enum: - A - B - C - D - E - F - G - H - I - J - K - L - M taxCountry: type: string description: >- The US country or territory the investor is a US person of. `US`, or a territory code. enum: - US - PR - GU - VI - UM - MP - AS certification: $ref: '#/components/schemas/W9Certification' W9Receipt: type: object description: The receipt for a W-9 now on file for the investor. required: - formType - submittedAt properties: taxFormId: type: string description: >- Securitize's identifier for this tax form. Quote it to Securitize support about the form. Absent in the rare case the form was put on file but its identifier could not be read back; the form is on file all the same. examples: - 5c2fe256-5474-4f5f-8d02-595b058ae698 formType: type: string enum: - W-9 submittedAt: type: string format: date-time description: When Securitize received the form (ISO 8601, UTC). ApiError: type: object description: > The error envelope of the API. Branch on `code`; `message` is for humans and not contractual. Quote `correlationId` to Securitize support. required: - statusCode - code - message - correlationId properties: statusCode: type: integer description: The HTTP status, repeated. code: type: string description: > Stable error code. Each response lists the codes it can carry and what to do about each. message: type: string description: Human-readable explanation. Not a stable contract. details: description: > Present on some errors. Its shape depends on the error: - body validation — an array of `{ field, message }`; - path or query validation — an array of strings; - `external_investor_id_conflict` — `{ investorId }`; - `external_key_party_id_conflict` — `{ keyPartyId }`; - submit refusal — `{ investor, keyParties }`, the per-subject accounting; - document refused, or not accepted while under review — `{ code, message }`; - document outcome unknown — `{ code }`, possibly empty; - `suitability_not_verified` — `{ notVerified }`; - `tax_form_type_not_allowed` — `{ allowed }`; - `tax_form_already_active` — `{ activeTaxForm }`; - DLT test locked, suitability under review or not approved, compact suitability for an entity, or a W-9 subject to backup withholding sent as data — `{ reason }`. anyOf: - $ref: '#/components/schemas/FieldErrors' - $ref: '#/components/schemas/MessageErrors' - $ref: '#/components/schemas/InvestorConflictDetails' - $ref: '#/components/schemas/KeyPartyConflictDetails' - $ref: '#/components/schemas/SubmitRefusalDetails' - $ref: '#/components/schemas/RefusalDetails' - $ref: '#/components/schemas/OutcomeUnknownDetails' - $ref: '#/components/schemas/SuitabilityGateDetails' - $ref: '#/components/schemas/AllowedTaxFormsDetails' - $ref: '#/components/schemas/ActiveTaxFormDetails' - $ref: '#/components/schemas/ReasonDetails' correlationId: type: string description: Identifier of this request. Quote it to Securitize support. examples: - partners-api-d3dcfc7c-a3d0-459e-98a5-9d6f23dcb998 SecuritizeId: type: string minLength: 1 description: > Identifier assigned by Securitize, opaque and specific to your partner account. Store it as an opaque string. examples: - 6aca84e5dc49fe8369dd1da4 W9Certification: type: object description: >- The certification the investor made in your flow (W-9 Part II, under penalties of perjury), on the certification text Securitize publishes. An object; a list or any other value answers `400 validation_error`. required: - certifiedAt - signatureName - subjectToBackupWithholding - isUSPerson - certificationTextVersion properties: certifiedAt: type: string format: date-time pattern: ^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d{1,9})?(Z|[+-]\d{2}:\d{2})$ description: >- When the investor agreed to the certification, as an ISO 8601 date-time with seconds and an offset (`Z` or `±hh:mm`). Not in the future, give or take 5 minutes of clock difference. examples: - '2026-10-28T15:28:40Z' signatureName: type: string minLength: 1 maxLength: 100 description: >- The name the investor signed with. For an entity, the name of the person who signs on its behalf. Trimmed. examples: - Jane Test subjectToBackupWithholding: type: boolean description: >- `true` when the investor unchecked the certification box because the IRS notified them they are subject to backup withholding (item 2 does not apply to them). Only `false` is accepted: `true` answers `422 business_rule_violation`, with `details.reason` `backup_withholding_not_supported`. isUSPerson: type: boolean const: true description: >- The investor certified being a U.S. citizen or other U.S. person (item 3). Must be `true`. certificationTextVersion: type: string enum: - w9-sm-2026-10 description: >- The version of the certification text the investor was shown. See [The certification](/secid-api/tax-forms#the-certification). FieldErrors: type: array description: Body validation — one entry per offending field. items: type: object required: - field - message properties: field: type: string description: >- Path of the field, with dots and indexes, e.g. `phone.code` or `files.0.content`. message: type: string description: What is wrong with it. MessageErrors: type: array description: Path or query validation — one message per problem. items: type: string InvestorConflictDetails: type: object description: The investor that already holds the identifiers sent. required: - investorId properties: investorId: $ref: '#/components/schemas/SecuritizeId' description: The existing investor's id. Use it instead of creating another. KeyPartyConflictDetails: type: object description: The key party that already holds the `externalKeyPartyId` sent. required: - keyPartyId properties: keyPartyId: $ref: '#/components/schemas/SecuritizeId' description: The existing key party's id. SubmitRefusalDetails: type: object description: Per-subject accounting of a refused submit. Nothing was submitted. required: - investor - keyParties properties: investor: $ref: '#/components/schemas/SubmissionOutcome' description: The investor itself. keyParties: type: array description: >- Each key party of an entity; the ones not ready read `failed` with a reason. Empty for an individual. items: $ref: '#/components/schemas/SubmissionOutcome' RefusalDetails: type: object description: The verification side's own refusal of a document. required: - code - message properties: code: type: string description: >- Refusal code, for example `corrupted-file`. Not a fixed list; read `message`. message: type: string description: Human-readable explanation. OutcomeUnknownDetails: type: object description: A document whose outcome is unknown. May be empty. properties: code: type: string description: Reason code, when there is one. SuitabilityGateDetails: type: object description: Which suitability is not verified yet. required: - notVerified properties: notVerified: type: array description: '`us` (the suitability) and/or `eu` (the DLT test).' items: type: string enum: - us - eu AllowedTaxFormsDetails: type: object description: The tax forms this investor can receive. required: - allowed properties: allowed: type: array items: $ref: '#/components/schemas/TaxFormType' ActiveTaxFormDetails: type: object description: The tax form the investor has on file. required: - activeTaxForm properties: activeTaxForm: type: object required: - taxFormId properties: taxFormId: type: string description: Securitize's identifier for the form on file. formType: $ref: '#/components/schemas/TaxFormType' ReasonDetails: type: object description: A machine-readable reason. required: - reason properties: reason: type: string description: >- For example `dlt_test_locked`, `suitability_under_review` or `investor_type_not_supported`. Each operation lists the reasons it can answer. TokenError: type: object additionalProperties: false description: > The gateway's answer to a missing, invalid or expired bearer token, in the OAuth 2.0 shape: `error` and `error_description`, no `code` and no `correlationId`. The request never reached the API. required: - error - error_description properties: error: type: string enum: - invalid_request - invalid_token description: > `invalid_request`: no `Authorization: Bearer` header. `invalid_token`: the token is unknown or has expired. error_description: type: string GatewayError: type: object additionalProperties: false description: > The gateway's error shape: only `message`, no `code` and no `correlationId`. It means the request never reached the API — check the account or the path, not the payload. required: - message properties: message: type: string description: > `You cannot consume this service` (`403`: your account is not enabled for this API), `IP address not allowed: ` (`403`: a path or method outside the API). SubmissionOutcome: type: object description: >- What happened to one subject — the entity itself or one of its key parties. required: - subjectId - result properties: subjectId: $ref: '#/components/schemas/SecuritizeId' description: The `investorId` for the investor itself, or a `keyPartyId`. result: type: string enum: - submitted - skipped - failed - not_attempted description: > `submitted` — handed over on this call (a company key party: recorded for compliance review). `skipped` — already handed over, not re-sent; this makes repeats safe. `failed` — attempted and refused; see `reason`. `not_attempted` — never reached; a repeat sends exactly these. reason: $ref: '#/components/schemas/SubmissionReason' TaxFormType: type: string description: > The form in the file. `W-9` for a US person, individual or entity; `W-8BEN` for an individual who is not a US person; `W-8BEN-E` for an entity that is not a US person. enum: - W-9 - W-8BEN - W-8BEN-E SubmissionReason: type: object description: > Why a subject was not submitted. Branch on `code`; `message` is for humans and not contractual. Known values: `already-handed-over` (already with verification, not re-sent), `documents-incomplete` (something is still owed), `provider-rate-limited` and `submission-failed` (the hand-over did not go through; call submit again), `key-parties-not-ready` (an entity waits for its key parties). Treat any other value as "not submitted; read `message`". required: - code - message properties: code: type: string description: Stable reason code. message: type: string description: Human-readable explanation. responses: GatewayUnauthorized: description: > Refused by the gateway: no bearer token, or one that is unknown or has expired. The request never reached the API. Get a new token and send the request again. headers: WWW-Authenticate: description: >- `Bearer realm="service"`, with `error` and `error_description` when a token was sent. schema: type: string content: application/json: schema: $ref: '#/components/schemas/TokenError' examples: missing: summary: No Authorization header value: error_description: The access token is missing error: invalid_request invalid: summary: Unknown or expired token value: error_description: The access token is invalid or has expired error: invalid_token GatewayForbidden: description: > Refused by the gateway: the token is valid but your account is not enabled for this API. The request never reached the API. Contact Securitize to have it enabled. content: application/json: schema: $ref: '#/components/schemas/GatewayError' examples: notEnabled: summary: Account not enabled for this API value: message: You cannot consume this service InvestorNotFound: description: > `investor_not_found` — no investor with this id in your account: a typo, an id of another partner, an id of the other investor type (an individual where an entity is expected), or your `externalInvestorId` where Securitize's `investorId` is expected. Recover the `investorId` with `GET /investors?externalInvestorId=…`. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - investor_not_found examples: notFound: summary: Unknown investor value: statusCode: 404 code: investor_not_found message: Investor not found correlationId: partners-api-d8899b8a-ff77-4819-a2f0-4db50be1f634 ContentTypeNotJson: description: > `mime_not_supported` — the request's `Content-Type` is not `application/json`. Send JSON with that header. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - mime_not_supported examples: notJson: summary: Body sent as text value: statusCode: 415 code: mime_not_supported message: 'Content-Type must be application/json (received: "text/plain")' correlationId: partners-api-4d8f2a6c-1b9e-4c37-a05d-8e6f3b2c9a14 InternalError: description: > `internal_error` — an unexpected fault on Securitize's side. The message is always generic. Retry; if it persists, send the `correlationId` to Securitize support. content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiError' - properties: code: type: string enum: - internal_error examples: internal: summary: Internal error value: statusCode: 500 code: internal_error message: Internal error correlationId: partners-api-5b0c7a1e-9d3f-4e2a-8c6b-1f4d2e3a9b70 examples: InvestorNotOwned: summary: Limited access (investor_not_owned) value: statusCode: 409 code: investor_not_owned message: >- This investor's verification is led by another party; you can read its status and manage its wallets, token whitelisting, suitability and DLT test, but not change its data or documents. correlationId: partners-api-9599b8a2-d164-5cb3-b057-2019ae3b8e87 securitySchemes: OAuth2: type: oauth2 description: > OAuth 2.0 client credentials. Exchange the client id and secret Securitize issued you for a bearer token at the token URL (the host root, not under the base URL), with `grant_type=client_credentials`; the token lasts 2 hours and goes in the `Authorization: Bearer` header of every request. No scope is needed. The token identifies your partner account, so you never send a partner id, and every record you create is scoped to you. flows: clientCredentials: tokenUrl: https://partners-api.sandbox.securitize.io/oauth2/token scopes: {} ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.