# tZERO

> tZERO Technologies builds regulated infrastructure for tokenized real-world assets and digital
> securities. Through an SEC- and FINRA-regulated broker-dealer, the tZERO Alternative Trading System
> (operating continuously since 2019), a special purpose broker-dealer for digital custody and an
> SEC-registered transfer agent, it covers capital formation, token issuance, secondary trading,
> market data, clearance and settlement, cap-table recordkeeping, corporate actions, dividends and
> proxy voting. Its developer surface is marketed as tZERO Connect.

This file was generated by API Evangelist from tZERO's published contracts and documentation on
2026-09-01. tZERO does not publish an llms.txt of its own (/llms.txt returns 404 on tzero.com,
apidocs.tzero.com and api.t0direct.com).

## APIs

- [tZERO Issuance & Secondary Markets API](https://apidocs.tzero.com/docs/explorer): OpenAPI 3.0.3, 33 operations over 27 paths at https://gateway-web-api.tzero.com/app — account onboarding, KYC, primary offerings and investments, bank accounts and transfers, balances, market schedules and public price data, and order entry on the tZERO ATS.
- [tZERO Institutional API](https://apidocs.tzero.com/docs/institutional): OpenAPI 3.0.3 v1.1.0, 102 operations over 86 paths at https://api.t0direct.com/api/v1 — transfer-agent, tokenization and custody operations: investors, securities and cap tables, book-entry transfers, issuance requests, documents, dividends, corporate actions, voting proposals, settlement instructions, token deployments, custody vaults and webhooks.
- [tZERO FIX API](https://apidocs.tzero.com/docs/fix): FIX 4.2 order entry and IOI market data; FIX 4.4 drop copy and market data, specified message by message and tag by tag.

## Specs

- [Issuance & Secondary Markets OpenAPI](https://apidocs.tzero.com/api/openapi-spec)
- [Institutional OpenAPI](https://api.t0direct.com/api/v1/openapi.json)

## Docs

- [tZERO API overview](https://apidocs.tzero.com/docs)
- [REST API explorer](https://apidocs.tzero.com/docs/explorer)
- [Institutional API reference](https://api.t0direct.com/api/v1/docs/)
- [FIX order entry (4.2)](https://apidocs.tzero.com/docs/fix/order-entry)
- [FIX drop copy (4.4)](https://apidocs.tzero.com/docs/fix/drop-copy)
- [FIX market data (4.4)](https://apidocs.tzero.com/docs/fix/market-data)
- [FIX IOI market data](https://apidocs.tzero.com/docs/fix/ioi-market-data)
- [tZERO Connect (API suite and partner network)](https://www.tzero.com/connect)

## Authentication

- Issuance & Secondary Markets: an `x-apikey` header plus a bearer JWT from `POST /auth/v1/api/token` (1-hour lifetime, refreshable at `POST /auth/v1/api/refresh`). Keys are issued by tZERO — there is no self-serve API signup.
- Institutional: a single scoped `X-API-Key` header. Scopes include TA_READ, TA_WRITE, TA_TRANSFERS, TA_ADMIN, TOKENS_READ, DEPLOYMENTS_READ, CUSTODY_READ and FULL_ACCESS; a missing scope returns 403.

## Runtime semantics

- Idempotency: `Idempotency-Key` header on Institutional dividend/corporate-action/proposal mutations (409 on key reuse with a different payload); an `idempotencyKey` body field on transfers and issuances; a client-supplied `transactionId` body field on Issuance & Secondary Markets investments and orders.
- Pagination: Institutional list endpoints take `page` / `perPage` and return `pagination` (total, page, perPage, totalPages). The Issuance & Secondary Markets API publishes no pagination.
- Errors: no RFC 9457. Issuance & Secondary Markets returns `{"errors":[{code,message,field,details}]}` with 57 named business-validation codes published in the spec; the Institutional API returns `{"success":false,"error":{code,message}}` with T0K-prefixed codes.
- Webhooks: Institutional only — subscription CRUD, HMAC-SHA256 signed payloads, a test-send endpoint, and `ta.dividend.*` / `ta.corporate_action.*` / `ta.proposal.*` event families. No AsyncAPI is published.
- Rate limits: none published, on either surface.
- Reversibility: `cancelOrder` (422 once no longer cancellable), `cancelInvestment` (INVESTMENT_CANNOT_BE_CANCELLED), Institutional settlement `cancel` before execution and `reverse` after, and `cancel` on dividends, corporate actions and proposals.

## Company

- [Website](https://www.tzero.com/)
- [Company](https://www.tzero.com/company)
- [Tokenize](https://www.tzero.com/tokenize)
- [Trade](https://www.tzero.com/trade)
- [Connect](https://www.tzero.com/connect)
- [Content hub](https://www.tzero.com/content-hub)
- [Legal hub, disclosures and Form CRS](https://www.tzero.com/legal)
- [Contact](https://www.tzero.com/contact)
- [Sign up](https://platform.tzero.com/tzero/register)
- [Sign in](https://platform.tzero.com/tzero/auth)