> ## 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=<stock token id>&partnerUrl=<return URL> (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).

# Errors

> How errors look, what to do about each code, when the socket closes, and what is safe to retry.

**A refusal does not close the socket.** A refused order costs an order, not the session. Only a failed `hello`, a well-formed message before the session is open, and an oversized frame close it. A malformed frame answers `MALFORMED` and the socket stays open, before `hello` as after.

## How an error looks

```json theme={null}
{
  "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"
  }
}
```

Branch on `code`; `message` is for people and can change. The error carries the `requestId` of the message that caused it when the frame could be parsed far enough; a frame refused at envelope level (a malformed envelope, duplicate keys) gets an `error` without it. Quote `traceId` when you contact Securitize.

## What to do

| `code` | Socket | Meaning | What to do |
| - | - | - | - |
| `SIGNATURE_INVALID` | Closed, on `hello` | The signature does not verify, or the public key is not registered | Check that you sign the exact payload string you send, and that the key is registered. See [Signing](https://developers.securitize.io/cet-underlying-api/sandbox-and-auth.md#signing) |
| `TIMESTAMP_OUT_OF_WINDOW` | Open | The `timestamp` is more than 30 seconds from the server clock | Fix NTP. Reconnecting does not help |
| `UNAUTHENTICATED` | Closed | A message arrived before the session was open | Send `hello` first and wait for `welcome` |
| `MALFORMED` | Open | Not parseable, a required field missing, or fields that contradict each other: a `MARKET` order with a `limitPrice`, both `quantity` and `notional` or neither. Also a second `hello` on an open session, and a malformed frame sent before `hello` | Fix the message |
| `INVALID_ORDER` | Open | Well formed and refused on its merits, with the reason in `message`: a duplicate `externalRef`, a buy your own cash cannot cover, a `MARKET` buy, an order by `notional`, `Insufficient buying power`, a sell your redemption balance or the redemption wallet cannot cover, a symbol your account does not trade (mistyped or not), or the broker's own refusal in its words | A duplicate may be your own earlier order: look it up with `get_order` by `externalRef`. Otherwise fix the order, fund your cash or transfer the CETs, then send it again |
| `NOT_PERMITTED` | Open | The key is registered as read-only: it may read and receive pushes, but not `place_order`, `cancel_order` or `submit_crypto_funding` | Trade with a key registered for trading |
| `INVALID_SYMBOL` | Open | On `place_order`: a symbol your account trades that the broker no longer recognises; `message` names it. On `get_redemption_address` and `get_redemption_balance`: the symbol and chain are not ones you can trade, or (address only) the CET cannot be redeemed | Check it against `get_symbols` |
| `ORDER_NOT_FOUND` | Open | No such order on the session's account | Check the id. By `externalRef`, after an `UNKNOWN`: the order never reached the broker, and resending it is safe |
| `ORDER_NOT_CANCELLABLE` | Open | The order's state does not allow it: already filled or cancelled. `message` carries the broker's words | Read the order |
| `UPSTREAM_UNAVAILABLE` | Open | The broker could not be reached, or a buy's cash or a sell's redemption wallet could not be checked. The fate of an order sent with it is unknown. On `hello`: the key could not be checked at that moment. On `submit_crypto_funding`: the chain could not be read, or no answer came in time | Look the order up with `get_order` by `externalRef` before resending. On `hello`, send a new `hello` with a new `nonce` on the same socket. On `submit_crypto_funding`, send the same `txHash` again: it is never credited twice |
| `DEPOSIT_PENDING` | Open | On `submit_crypto_funding`: the transaction is not on chain yet, or not final. Nothing was credited | Send the same `txHash` again later |
| `DEPOSIT_REFUSED` | Open | On `submit_crypto_funding`: the deposit will not be credited as sent. `message` says why: crypto funding is not enabled on that chain, there is no USDC transfer from one of your wallets to Securitize's, the transaction failed, or it was already credited to another account | Nothing to retry. See [Fund your cash with crypto](https://developers.securitize.io/cet-underlying-api/positions-and-cash.md#fund-your-cash-with-crypto) |
| `RATE_LIMITED` | Open | The service is throttling requests | Retry after a pause |
| `INTERNAL` | Open | A fault on Securitize's side, not a problem with the request | Retry with backoff; if it persists, contact Securitize with the `traceId` |

Treat a code you do not recognise as a refusal of that message, not as a reason to drop the session.

The [reads over HTTP](https://developers.securitize.io/cet-underlying-api/reference/http-reads.md#errors) answer the same codes, with an HTTP status.

## Close codes

| Code | Meaning | What to do |
| - | - | - |
| `4001` | Authentication failed or expired. Also sent, with reason `UNAUTHENTICATED` and no `error` first, when no valid `hello` arrives within 10 seconds of connecting | Check the key and the signature, send `hello` first, then open a new session |
| `4008` | Policy: the socket was idle for 3 minutes | Keep sending `ping`, then reconnect |
| `1009` | A frame over 64 KB. No `error` is sent first | Keep every frame under 64 KB, then reconnect |
| `1001` | The server is going away, usually a release | Reconnect with backoff and [reconcile](https://developers.securitize.io/cet-underlying-api/track-orders.md#after-a-disconnect) |
| `1006`, or any other | The connection dropped or closed | Reconnect with backoff and [reconcile](https://developers.securitize.io/cet-underlying-api/track-orders.md#after-a-disconnect) |

## What is safe to retry

| Message | Send it again |
| - | - |
| `place_order` | Safe with the same `externalRef`: a reference an order already uses is refused, never duplicated, except that the reference of an order refused before it reached the broker can be used again. A reference the broker itself refused stays taken for the rest of the day: resending it answers `INVALID_ORDER` as a duplicate, so use a new one. After `UNKNOWN`, resend it unchanged or look it up; after `UPSTREAM_UNAVAILABLE`, look the order up first |
| `cancel_order` | Safe. After an `UNKNOWN`, read the order instead |
| `submit_crypto_funding` | Safe with the same `txHash`: a transaction is credited once, and sending it again answers the same credit |
| Reads and `ping` | Safe |
| `hello` | With a new `nonce`: on the same socket after `UPSTREAM_UNAVAILABLE` or `TIMESTAMP_OUT_OF_WINDOW` (fix the clock first), otherwise on a new socket |

## Getting help

When you contact Securitize about a message, send:

* the `traceId` of the reply or push;
* your `externalRef`, and the `orderId` and `regulatoryId` if you have them;
* the message `type`, when you sent it, and whether it was sandbox or production;
* the `code` you received, and what you expected instead.

Never send your private key. The `traceId` is enough for Securitize to find the exchange.


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