Seed 2.1 Turbo and Hy4 preview are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Seed 2.1 Turbo, from bytedance-seed, has a 262,144-token context window and is priced at $0.50/M tokens input, $2.50/M tokens output on OpenRouter.
Hy4 preview, from tencent, has a 1,048,576-token context window and is priced at $0.834/M tokens input, $2.501/M tokens output on OpenRouter.