# ThetaData

**Canonical:** https://apis.io/providers/thetadata/  
**Website:** https://thetadata.net/  
**APIs profiled:** 14

ThetaData is a developer-first US market data vendor founded in 2022 by Bailey Danseglio, selling real-time and historical options, stocks, indices, and interest-rates data with unfiltered tick-level trades, quotes, and Greeks. Delivery is self-serve via the Theta Terminal, a local Java application that authenticates with an API key or account credentials and exposes a local REST API (127.0.0.1:25503/v3), a WebSocket streaming API (127.0.0.1:25520), and an MCP server, backed by a published OpenAPI 3.1 spec, Python library, flat files, and tiered monthly subscriptions.

## Kin Score — 62.1 / 100 (strong)

Scored 2026-08-17 under rubric 0.11.0. Trend: flat (+0.0 from 62.1).

| Facet | Score |
|---|---|
| Discoverability | 81.5 |
| Contract Quality | 57.2 |
| Governance | 11.5 |
| Operational Transparency | 81.6 |
| Developer Ergonomics | 71.2 |
| Commercial Clarity | 76.3 |

Regulatory layer — **Securities & Market Data**: 51.7 (matched via tags).

## Agent readiness — 44.8 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | documented |
| Error Semantics | documented |
| OpenAPI Examples | verified |
| Rate Limit Signal | documented |
| Event Surface Described | derived |
| Agent Skills | derived |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Freemium, self-service signup — onboarding: unknown, pricing: freemium, trial: yes (confidence: high).

## APIs (14)

- **ThetaData Streaming WebSocket API** — JSON WebSocket streaming of US stock trade/quote, options trade/quote, and index price streams, served locally by the Theta Terminal at ws://127.0.0.1:25520/v1/events. Requires ...
- **ThetaData MCP Server** — Model Context Protocol server built into Theta Terminal v3, exposing the full v3 API to LLM CLIs (documented for Claude CLI and Gemini CLI) over SSE at http://127.0.0.1:25503/mc...
- **ThetaData At-Time API** — The At-Time API from ThetaData — 5 operation(s) for at-time.
- **ThetaData Calendar API** — The Calendar API from ThetaData — 3 operation(s) for calendar.
- **ThetaData FlatFile API** — The FlatFile API from ThetaData — 6 operation(s) for flatfile.
- **ThetaData History API** — The History API from ThetaData — 26 operation(s) for history.
- **ThetaData Index API** — The Index API from ThetaData — 10 operation(s) for index.
- **ThetaData Interest Rate API** — The Interest Rate API from ThetaData — 1 operation(s) for interest rate.
- **ThetaData List API** — The List API from ThetaData — 9 operation(s) for list.
- **ThetaData Option API** — The Option API from ThetaData — 37 operation(s) for option.
- **ThetaData Single Day API** — The Single Day API from ThetaData — 2 operation(s) for single day.
- **ThetaData Snapshot API** — The Snapshot API from ThetaData — 17 operation(s) for snapshot.
- **ThetaData Stock API** — The Stock API from ThetaData — 15 operation(s) for stock.
- **ThetaData Year API** — The Year API from ThetaData — 1 operation(s) for year.

## MCP servers (1)

- **thetadata-mcp.yml**

## Security (2)

- **Thetadata Authentication** — apiKey/credentials · 2 schemes
- **Thetadata Domain Security** — TLSv1.3 · DNSSEC · DMARC

## Plans (1)

- **Thetadata Plans**

## Tags

Financial, Market Data, Options, Stocks, Indices, Real-Time, Historical Data, Trading

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/thetadata/). Scores are computed from the provider's own public artifacts under a published rubric.