> ## 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). # CET Underlying API > Buy and sell the shares underlying CETs over one WebSocket; Securitize mints and burns the CETs to match. A Convertible Entitlement Token (CET) stands for one share of a listed company. The CET Underlying API trades those shares: you buy and sell them over one authenticated WebSocket, and Securitize mints CETs as your buys fill and burns them as your sells fill. These docs are for the engineers building the integration and for the operations people reconciling what it does. ## How it works | You | Securitize | | - | - | | Register an Ed25519 public key, and the wallet that receives your CETs | Holds only the public key; mints to that wallet | | Place a buy, a limit order in shares | Holds its cost against your own cash, routes it to the broker, and mints one CET per share as it fills | | Send CETs to the redemption wallet, then place a sell | Refuses a sell the wallet cannot cover; routes the rest, and burns those CETs as it fills | | Keep your cash funded | Refuses a buy your own cash cannot pay for | | Follow your orders on the stream, and read them back after any gap | Pushes order, trade, mint and burn updates; answers reads of orders, mints, burns and cash | One socket carries all of it. There is no subscription step: once the session is open, it receives every update for your account. The reads of orders, mints, burns, cash and your redemption balance are also served as signed `GET` requests, for when you only need to ask: see [Reads over HTTP](https://developers.securitize.io/cet-underlying-api/reference/http-reads.md). ## The whole picture 1. **Connect** to the socket and open a session with a signed `hello`. `get_symbols` lists what you can trade, and on which chains. 2. **Buy**: `place_order` with side `B`. The `ack` means the order was taken; the fills arrive as `order_updated` and `trade_updated`. CETs are minted to your wallet as the order fills, often in more than one mint, and each mint is pushed as `mint_updated`. 3. **Sell**: send the CETs to the redemption wallet, then `place_order` with side `S` and a `quantity`. The CETs are burned as the order fills, and each burn is pushed as `burn_updated`. 4. **Reconcile**: `get_order`, `get_mints` and `get_burns` say what happened, whatever the stream delivered. > [card] [Sandbox and authentication](https://developers.securitize.io/cet-underlying-api/sandbox-and-auth.md) > > Connect, sign, open a session. > [card] [Buy shares and receive CETs](https://developers.securitize.io/cet-underlying-api/buy-shares.md) > > Place a buy and reconcile the CETs minted. > [card] [Sell shares and redeem CETs](https://developers.securitize.io/cet-underlying-api/sell-shares.md) > > Return the CETs, place the sell, reconcile the burns. > [card] [Track, cancel and reconcile orders](https://developers.securitize.io/cet-underlying-api/track-orders.md) > > The stream, disconnects, `UNKNOWN`, cancels and executions. > [card] [Cash](https://developers.securitize.io/cet-underlying-api/positions-and-cash.md) > > Your own cash, its movements, and what a buy is checked against. > [card] [Go-live checklist](https://developers.securitize.io/cet-underlying-api/go-live-checklist.md) > > What to check in sandbox before production. ## Before you start * **An agreement with Securitize.** It sets the symbols you can trade and the CET each one maps to, which `get_symbols` lists with their chains. `get_redemption_address` answers the redemption wallet of each CET. * **Two registrations with Securitize**: your Ed25519 public key, and the wallet that receives your CETs. * **Sandbox** is where you build and test. See [Sandbox and authentication](https://developers.securitize.io/cet-underlying-api/sandbox-and-auth.md). * **Production** uses the same messages at a production endpoint, arranged with Securitize once your integration passes the [go-live checklist](https://developers.securitize.io/cet-underlying-api/go-live-checklist.md). ## What makes this API different * **An `ack` is not a fill.** It says the order was taken. Fills arrive afterwards, pushed. * **The stream is a convenience, not a record.** Updates are delivered at most once and nothing is queued while you are disconnected. After any gap, the reads say where things stand. * **A sell needs its CETs first.** A sell is refused unless CETs you transferred to the redemption wallet, and that are not held by your other sells, cover it (`get_redemption_balance`). It must be placed by `quantity`. * **A buy is paid from your own cash.** It is a `LIMIT` order by `quantity`, and its cost at the limit, plus fees, is held against your `available` (`get_cash_balance_v2`) before it reaches the broker. A buy that cash does not cover is refused. * **`externalRef` is your idempotency key.** A reference an order already uses is refused, never duplicated, so resending after a timeout is safe. An order Securitize refuses before sending it leaves its reference usable; one the broker refused keeps it for the rest of the day, so send the order again under a new reference. * **Every amount is a decimal string**, in both directions. Compare amounts as decimals, never as strings. ## Not available No quotes or market data: size orders with your own price feed. No push for settlement. No account field: the account is always the session's. Every message, field and example is in the API reference in the sidebar. 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