FastSubS API: connect your project
API keys, free connection checks, shared balance and safe request handling.
Start without a paid generation
- Sign in to your FastSubS account and create an API key in the account settings.
- Keep it on your server or in a secret environment variable. Never put it in a public repository, browser code or a URL.
- Use GET /v1/models and GET /v1/balance to check authentication. These reads do not start a generation or debit your balance.
Open your account · API documentation (text)
Connection example
Bash/curl example; FASTSUBS_API_KEY is your local secret variable, not a real key shown here.
curl https://fastsubs.org/v1/models \
-H "Authorization: Bearer $FASTSUBS_API_KEY"
curl https://fastsubs.org/v1/balance \
-H "Authorization: Bearer $FASTSUBS_API_KEY"Requests and costs
Base URL: https://fastsubs.org/v1. POST /v1/chat/completions starts a text request and may debit the account. Choose the model id returned by /v1/models; this endpoint lists available text models, not the entire media catalogue. Do not assume a fixed price for every prompt.
The API uses the balance of the key owner. Balance returns integer units and units_per_usd = 10000; do not interpret units as whole dollars. Availability and media settings may change: consult current options and quotes before a paid confirmation.
Streaming and delivery
For compatible text requests, stream: true enables progressive output. The documentation describes payloads and events. If the connection fails, do not blindly start the same paid request again. Reuse a stable Idempotency-Key for the same payload; a conflicting payload or already submitted operation can return 409. Keep the request id and inspect the saved result instead.
Saved media and 3D results require authentication and ownership. Downloading a ready result is not a new generation. This page does not enable unavailable providers or promise that every media model supports every parameter.