generated: '2026-07-22'
method: searched
source: >-
  https://docs.thetadata.us/Articles/Getting-Started/Getting-Started.html
  (Authentication section) and
  https://docs.thetadata.us/Python-Library/Getting-Started.html.
docs: https://docs.thetadata.us/Articles/Getting-Started/Getting-Started.html
description: >-
  ThetaData authenticates at the session level, not per HTTP request. The
  published OpenAPI declares security: [] because the local REST API served by
  the Theta Terminal (127.0.0.1:25503/v3) is an unauthenticated loopback
  surface; credentials are supplied when the terminal (or the Python library
  client) starts, which opens an authenticated session to ThetaData's MDDS
  servers. Requests are additionally IP-pinned to the first requester (error
  476 WRONG_IP) and a single terminal session is enforced (error 478
  INVALID_SESSION_ID).
summary:
  types: [apiKey, credentials]
  applied_at: session (Theta Terminal launch / ThetaClient construction), not per-request
  api_key_in: [cli-argument, environment-variable, dotenv-file]
  oauth2_flows: []
schemes:
  - name: api_key
    type: apiKey
    description: >-
      API key generated from the user portal (https://thetadata.net/portal).
      Requires Theta Terminal version 20260615+ or Python library 1.0.9+.
    provisioning: https://thetadata.net/portal
    delivery:
      - method: cli-argument
        example: java -jar ThetaTerminalv3.jar --api-key <key>
      - method: environment-variable
        name: THETADATA_API_KEY
      - method: dotenv-file
        notes: .env next to ThetaTerminalv3.jar (or --dotenv-dir), containing THETADATA_API_KEY
    priority: CLI argument, then environment variable, then .env file
  - name: credentials
    type: credentials
    description: >-
      Account email + password as an alternative to an API key. Terminal reads
      creds.txt (email line 1, password line 2) next to the JAR or via
      --creds-file; the Python library accepts email/password arguments, a
      creds_file path, or the THETADATA_CREDENTIALS_FILE environment variable.
python_library:
  priority: >-
    Explicit creds_file, then API key (api_key argument or THETADATA_API_KEY,
    including .env), then email/password arguments, then default creds.txt.
  transport: Authenticates over HTTPS; requests data over gRPC (no terminal needed).
local_rest_api:
  scheme: none (loopback)
  notes: >-
    openapi security is empty by design — only the local machine can reach the
    terminal's HTTP server; entitlements are enforced server-side per
    subscription (error 471 PERMISSION).