# Pricing Source: https://staging-docs.aiand.com/models/pricing/ ai& bills inference per token, deducted from your prepaid credit balance after each request completes. Top-up via [Credits & Top-Up](/billing/credits/). ## The formula ``` cost = (input_tokens / 1_000_000) × input_per_1m + (output_tokens / 1_000_000) × output_per_1m ``` Both `input_per_1m` and `output_per_1m` are **prices per 1 million tokens in your organization's billing currency** (USD or JPY, fixed at org creation), served on each model row via `GET /v1/models` together with the `currency` field. A model is only listed and callable if it has a price in your currency. ## Prompt caching Repeated prompt prefixes are detected automatically, and the reused leading portion is billed at a reduced **cached input** rate on models that offer one. The common pattern — a stable system prompt (and tools) followed by a growing conversation — means every turn after the first reuses the previous turn's prompt as its prefix, so that portion is discounted. No `cache_control` markers or code changes are required. When a model offers a cached rate, the cost becomes: ``` cost = (cached_tokens / 1_000_000) × cached_input_per_1m + (input_tokens − cached_tokens) / 1_000_000 × input_per_1m + (output_tokens / 1_000_000) × output_per_1m ``` The cached token count is reported back in the response `usage`, under the field your SDK expects: | API | Field | |-----|-------| | OpenAI Chat Completions | `usage.prompt_tokens_details.cached_tokens` | | OpenAI Responses | `usage.input_tokens_details.cached_tokens` | | Anthropic Messages | `usage.cache_read_input_tokens` | Streaming responses report the same count as `tokens.cached` in the `event: metrics` trailer (with `X-Aiand-Metrics: true`). - Caching applies to prompts of **1024 tokens or more**, counted in **128-token increments**. - Reuse is scoped to your organization and lasts roughly **10 minutes** of inactivity. - Only models with a cached input rate report `cached_tokens`; on other models all input bills at the standard rate and the field is omitted. ## Per-request reporting Send the request header `X-Aiand-Metrics: true` to receive the exact computed cost with each response: - **Non-streaming**: `X-Cost` + `X-Cost-Currency` headers. See [Response Headers](/reference/response-headers/). - **Streaming**: a trailing `event: metrics` SSE event after the model's terminal message. Its payload includes the token counts, `cost`, and a `currency` field telling you what currency the cost is denominated in. See [Streaming Events](/reference/streaming-events/). You can also query usage and cost retrospectively via the [Analytics](/analytics/metrics/) and [Request Logs](/analytics/logs/) endpoints. ## When you're charged | Outcome | Charged? | |---------|----------| | 2xx response with output | Yes — `(input × rate) + (output × rate)` | | 4xx before model dispatch (validation, auth, rate limit, no credit) | No | | 5xx after partial output streamed | Yes for what was billed; the cost reflects what was produced | | Stream cancelled mid-flight | Yes for tokens already produced | Cost is deducted atomically when the request settles — concurrent requests can't overdraw. ## Tiers Token rates are the same across tiers. What differs is throughput — see [Rate Limits](/reference/rate-limits/) for per-tier RPM/TPM caps.