> ## 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). # Session > Open the socket, sign hello, and keep the session alive with ping. Connect to `wss://partners-rt-gw.sandbox.securitize.io/v1/market-maker/stream`, send a signed `hello` within 10 seconds, and wait for `welcome`; any other well-formed message first is refused with `UNAUTHENTICATED` and closes the socket, while a malformed frame answers `MALFORMED` and the socket stays open. Send `ping` every 10 seconds. One socket is one session. See [Sandbox and authentication](https://developers.securitize.io/cet-underlying-api/sandbox-and-auth.md) for signing and a working example. ## AsyncAPI ````yaml cet-underlying-api/asyncapi.yaml session id: session title: Session description: > Open the socket, send a signed `hello` within 10 seconds, and wait for `welcome`. A socket with no valid `hello` by then is closed with `4001`. Any other well-formed message before `welcome` is refused with `UNAUTHENTICATED` and the socket closes; a malformed frame answers `MALFORMED` and the socket stays open. Send `ping` every 10 seconds; a socket quiet for three minutes is closed with `4008`. A single frame may not exceed 64 KB; a larger one closes the socket with `1009`, without an `error` first. The session is bound to the socket: a second connection is a second session, and a second `hello` on an open session is refused with `MALFORMED` while the first session stands. servers: - id: sandbox protocol: wss host: partners-rt-gw.sandbox.securitize.io bindings: [] variables: [] address: /v1/market-maker/stream parameters: [] bindings: [] operations: - &ref_4 id: openSession title: Open a session description: Send a signed hello; the server answers welcome. type: receive messages: - &ref_7 id: hello payload: - name: hello description: Opens the session. Signed. The first message on every connection. type: object properties: - name: type type: string description: hello required: true - name: requestId type: string description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. required: false - name: timestamp type: integer description: >- Unix seconds when you signed the message. Must be within 30 seconds of the server clock. required: true - name: payload type: object required: true properties: - name: publicKey type: string description: >- Your registered Ed25519 public key, base58. It identifies you and verifies the signature in one value. required: true - name: nonce type: string description: >- A value you never repeat; a UUID is ideal. A nonce already used answers `SIGNATURE_INVALID`. It stops a captured `hello` from being replayed to open a second session. required: true - name: signature type: string description: >- base58( Ed25519-Sign( privateKey, timestamp + "." + type + "." + payloadBytes ) ), over the exact bytes of `payload` as sent. required: true headers: [] jsonPayloadSchema: type: object required: - type - timestamp - payload - signature properties: type: type: string const: hello x-parser-schema-id: requestId: &ref_0 type: string maxLength: 64 description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. x-parser-schema-id: RequestId timestamp: type: integer description: >- Unix seconds when you signed the message. Must be within 30 seconds of the server clock. x-parser-schema-id: Timestamp payload: type: object required: - publicKey - nonce properties: publicKey: type: string pattern: ^[1-9A-HJ-NP-Za-km-z]{43,44}$ description: >- Your registered Ed25519 public key, base58. It identifies you and verifies the signature in one value. x-parser-schema-id: nonce: type: string maxLength: 64 description: >- A value you never repeat; a UUID is ideal. A nonce already used answers `SIGNATURE_INVALID`. It stops a captured `hello` from being replayed to open a second session. x-parser-schema-id: x-parser-schema-id: signature: type: string maxLength: 128 description: >- base58( Ed25519-Sign( privateKey, timestamp + "." + type + "." + payloadBytes ) ), over the exact bytes of `payload` as sent. x-parser-schema-id: Signature x-parser-schema-id: HelloFrame title: Hello description: Opens the session. Signed. The first message on every connection. example: |- { "type": "hello", "requestId": "5c1d7e2a0b8f4c439d612f7a3e1b9c04", "timestamp": 1787900000, "payload": { "publicKey": "7xKXtg2C…", "nonce": "a3f9c1e7-6d2b-4e8a-b5f0-1c9d8e7a6b53" }, "signature": "3jK9…" } bindings: [] extensions: - id: x-parser-unique-object-id value: hello bindings: [] extensions: &ref_1 - id: x-parser-unique-object-id value: session - &ref_5 id: heartbeat title: Heartbeat description: Send ping every 10 seconds; the server answers pong with its clock. type: receive messages: - &ref_8 id: ping payload: - name: ping description: Heartbeat. Send one every 10 seconds. type: object properties: - name: type type: string description: ping required: true - name: requestId type: string description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. required: false headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string const: ping x-parser-schema-id: requestId: *ref_0 x-parser-schema-id: PingFrame title: Ping description: Heartbeat. Send one every 10 seconds. example: |- { "type": "ping", "requestId": "f0019a3c2b7e4d10a8c65e4f3d2c1b0a" } bindings: [] extensions: - id: x-parser-unique-object-id value: ping bindings: [] extensions: *ref_1 - &ref_6 id: sessionReplies title: Session replies description: What the server answers on the session channel. type: send messages: - &ref_9 id: welcome payload: - name: welcome description: The session is open. type: object properties: - name: type type: string description: welcome required: true - name: requestId type: string description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. required: false - name: traceId type: string description: >- The server's id for this exchange. Opaque; quote it when you contact Securitize. Not the `traceId` on a mint or a burn. required: true - name: sentAt type: string description: >- When the server put the message on the wire. ISO 8601, UTC, milliseconds. Not when anything happened at the broker. required: true - name: payload type: object required: true properties: - name: sessionId type: string description: The session's id. required: true - name: serverTime type: integer description: >- The server clock in Unix seconds. Compare it with yours on connect. required: true - name: heartbeatSeconds type: integer description: How often to send `ping`, in seconds. required: true headers: [] jsonPayloadSchema: type: object required: - type - traceId - sentAt - payload properties: type: type: string const: welcome x-parser-schema-id: requestId: *ref_0 traceId: &ref_2 type: string description: >- The server's id for this exchange. Opaque; quote it when you contact Securitize. Not the `traceId` on a mint or a burn. x-parser-schema-id: TraceId sentAt: &ref_3 type: string format: date-time description: >- When the server put the message on the wire. ISO 8601, UTC, milliseconds. Not when anything happened at the broker. x-parser-schema-id: SentAt payload: type: object required: - sessionId - serverTime - heartbeatSeconds properties: sessionId: type: string description: The session's id. x-parser-schema-id: serverTime: type: integer description: >- The server clock in Unix seconds. Compare it with yours on connect. x-parser-schema-id: heartbeatSeconds: type: integer description: How often to send `ping`, in seconds. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: WelcomeFrame title: Welcome description: The session is open. example: |- { "type": "welcome", "requestId": "5c1d7e2a0b8f4c439d612f7a3e1b9c04", "traceId": "partners-rt-gw-9f2c1b04-3e7d-4a1b-8c55-6d0e2f9a7b31", "sentAt": "2026-09-01T14:33:51.868Z", "payload": { "sessionId": "s-7f31a0", "serverTime": 1787900001, "heartbeatSeconds": 10 } } bindings: [] extensions: - id: x-parser-unique-object-id value: welcome - &ref_10 id: pong payload: - name: pong description: Answers ping, with the server clock. type: object properties: - name: type type: string description: pong required: true - name: requestId type: string description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. required: false - name: traceId type: string description: >- The server's id for this exchange. Opaque; quote it when you contact Securitize. Not the `traceId` on a mint or a burn. required: true - name: sentAt type: string description: >- When the server put the message on the wire. ISO 8601, UTC, milliseconds. Not when anything happened at the broker. required: true - name: payload type: object required: true properties: - name: serverTime type: integer description: The server clock in Unix seconds. required: true headers: [] jsonPayloadSchema: type: object required: - type - traceId - sentAt - payload properties: type: type: string const: pong x-parser-schema-id: requestId: *ref_0 traceId: *ref_2 sentAt: *ref_3 payload: type: object required: - serverTime properties: serverTime: type: integer description: The server clock in Unix seconds. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: PongFrame title: Pong description: Answers ping, with the server clock. example: |- { "type": "pong", "requestId": "f0019a3c2b7e4d10a8c65e4f3d2c1b0a", "traceId": "partners-rt-gw-2b8e4f61-9a0c-4d37-b2e5-7c1a6f3d8e90", "sentAt": "2026-09-01T14:36:31.102Z", "payload": { "serverTime": 1787900160 } } bindings: [] extensions: - id: x-parser-unique-object-id value: pong - &ref_11 id: error payload: - name: error description: A request was refused. Most errors leave the socket open. type: object properties: - name: type type: string description: error required: true - name: requestId type: string description: >- Your id for this message, echoed on its reply. Never interpreted or checked for uniqueness. Up to 64 characters are accepted, but keep it to 32, since an `error` echoes only the first 32 followed by `…`. A UUID without its hyphens is 32 characters. required: false - name: traceId type: string description: >- The server's id for this exchange. Opaque; quote it when you contact Securitize. Not the `traceId` on a mint or a burn. required: true - name: sentAt type: string description: >- When the server put the message on the wire. ISO 8601, UTC, milliseconds. Not when anything happened at the broker. required: true - name: payload type: object required: true properties: - name: code type: string description: >- One of `SIGNATURE_INVALID`, `TIMESTAMP_OUT_OF_WINDOW`, `UNAUTHENTICATED`, `NOT_PERMITTED`, `RATE_LIMITED`, `MALFORMED`, `INVALID_ORDER`, `INVALID_SYMBOL`, `ORDER_NOT_FOUND`, `ORDER_NOT_CANCELLABLE`, `DEPOSIT_PENDING`, `DEPOSIT_REFUSED`, `UPSTREAM_UNAVAILABLE`, `INTERNAL`. Treat a code you do not recognise as a refusal. required: true - name: message type: string description: For people. Can change; never branch on it. required: true headers: [] jsonPayloadSchema: type: object required: - type - traceId - sentAt - payload properties: type: type: string const: error x-parser-schema-id: requestId: *ref_0 traceId: *ref_2 sentAt: *ref_3 payload: type: object required: - code - message properties: code: type: string description: >- One of `SIGNATURE_INVALID`, `TIMESTAMP_OUT_OF_WINDOW`, `UNAUTHENTICATED`, `NOT_PERMITTED`, `RATE_LIMITED`, `MALFORMED`, `INVALID_ORDER`, `INVALID_SYMBOL`, `ORDER_NOT_FOUND`, `ORDER_NOT_CANCELLABLE`, `DEPOSIT_PENDING`, `DEPOSIT_REFUSED`, `UPSTREAM_UNAVAILABLE`, `INTERNAL`. Treat a code you do not recognise as a refusal. x-parser-schema-id: message: type: string description: For people. Can change; never branch on it. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: ErrorFrame title: Error description: A request was refused. Most errors leave the socket open. example: |- { "type": "error", "requestId": "7a02c4e158b34f9da0e23c6b1d7f8e45", "traceId": "partners-rt-gw-4d81e0a7-2c6f-4b19-9e3a-8f5d1c7b0a62", "sentAt": "2026-08-28T15:29:47.012Z", "payload": { "code": "INVALID_ORDER", "message": "The reference ref-2026-08-28-0001 already names an order (FILLED): look it up instead of placing it again" } } bindings: [] extensions: - id: x-parser-unique-object-id value: error bindings: [] extensions: *ref_1 sendOperations: - *ref_4 - *ref_5 receiveOperations: - *ref_6 sendMessages: - *ref_7 - *ref_8 receiveMessages: - *ref_9 - *ref_10 - *ref_11 extensions: - id: x-parser-unique-object-id value: session securitySchemes: - id: ed25519Signature name: ed25519Signature type: asymmetricEncryption description: > Each client registers an Ed25519 public key with Securitize beforehand; the private key never leaves the client. `hello`, `place_order`, `cancel_order`, `submit_crypto_funding`, `sandbox_deposit` and `sandbox_withdraw` carry `timestamp` (Unix seconds) and `signature` = base58( Ed25519-Sign( privateKey, timestamp + "." + type + "." + payloadBytes ) ), where `payloadBytes` are the exact bytes of `payload` as sent on the wire. The timestamp must be within 30 seconds of the server clock. Other messages ride on the session `hello` opens. extensions: [] ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.