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Billing basics

Langbly records usage per request:

  • charsIn: sum of input characters across all q items
  • charsOut: sum of output characters across all translations

By default, billing is based on input characters (charsIn). Some deployments may include output characters depending on configuration.

If your account has no active plan/credits, requests can return 429 RESOURCE_EXHAUSTED.

Frequently asked questions​

How is billing calculated per request?​

Each request is measured by charsIn (sum of all input characters across q[] items) and charsOut (sum of output characters). Standard billing only counts charsIn; some deployments also count charsOut depending on configuration.

What happens if my account has no active subscription or credits?​

Your API returns a 429 RESOURCE_EXHAUSTED error.

Why am I billed for 50 characters when my request was only 20 characters?​

Since August 1, 2026, there is a billing floor of 50 counted characters per request. If a request contains fewer than 50 characters (e.g., single words of 14-41 characters), we still bill 50 characters. This covers the fixed processing overhead that small requests incur. Translating full sentences or longer texts (well above 50 characters) is unaffected.

How can I avoid the billing floor for many short texts?​

Bundle several short texts into a single request using the q[] array. The floor applies to the sum of all texts in that request, not to each individual fragment. For example, sending five 10-character texts in one request totals 50 characters, meeting the floor exactly.

Does the free tier still offer a monthly allowance?​

Yes. The standard free tier includes 500,000 characters per month (exact amount may vary by account configuration).