ByteDance ships 19 active Doubao API SKUs in 2026 — chat tiers from $0.022/M output (Seed 1.6 Flash) up to $2.57/M (Seed 2.0 Pro flagship), plus four Seedream image models and four Seedance video models. All chat models share a 256K context window. Seed 2.0 and Seed 1.6 chat models support vision, tool calls, JSON output, streaming, and thinking mode. Doubao 1.5 sits on a smaller 32K context. The honest catch: Doubao's direct API path (Volcano Engine Ark) gates registration behind a Chinese-mainland phone number and real-name verification. The OpenAI-compatible aggregator path (TokenMix) skips that gate but charges what amounts to a parity-routed price. All numbers in this guide are from the TokenMix model registry pulled 2026-05-14. The "cheapest tier" line: doubao-seed-1.6-flash at $0.022 input / $0.219 output per million tokens — about 6x cheaper output than Doubao Seed 2.0 Pro and roughly an order of magnitude cheaper than GPT-5.5.…