Yi Lightning
01ai/yi-lightningSpeed-first bilingual model: symmetric pricing and sub-second answers for interactive products.
Model overview
Context window
64K
tokens
Input price
—
quoted on request
Output price
—
quoted on request
Weekly volume
—
tokens / week
Open weights
No
API only
Capabilities
3
of 11 tags
Description
Yi Lightning is a language model from 01.AI. Webparam does not stock this model yet and can source it on request — tell us what you need it for and we will come back with availability and a price. 01.AI’s stated focus is efficient bilingual frontier models. The weights are not published, so it is API-only.
Capabilities
- Tool calling
- Calls functions you define and returns their arguments as structured data, the basis of agents.
- JSON mode
- Constrains the response to valid JSON matching a schema you supply.
- Streaming
- Emits tokens as they are generated, so answers appear progressively rather than all at once.
Strengths & weaknesses
Strengths
- Fastest first token in the catalogue
- Symmetric in/out pricing
- Strong EN/ZH balance
Weaknesses
- 64K context only
- Depth trails larger models
Pricing
Free| Rate | Price | Unit |
|---|---|---|
| Input | $0.00 | per 1M tokens |
| Output | — not charged | — |
Free at the point of use; fair-use rate limits apply to the free tier. Illustrative placeholder pricing.
Context window
64Ktokens
covers prompt and response together, so a long input leaves less room for the answer.
Supported features
| Feature | Support |
|---|---|
| Tool calling | Supported |
| JSON mode | Supported |
| Streaming | Supported |
| Vision input | Not supported |
| Audio input | Not supported |
| Long context | Not supported |
| Open weights | Not supported |
| Reasoning | Not supported |
| Fine-tunable | Not supported |
| Batch | Not supported |
| Caching | Not supported |
Example use cases
Chat interfaces
Fastest first token in the catalogue
Autocomplete
Symmetric in/out pricing
Latency-critical features
Strong EN/ZH balance
Comparison
| Attribute | Yi Lightning | Doubao 1.5 Pro | GPT-5.1 Mini |
|---|---|---|---|
| Context window | 64K | 256K | 400K |
| Input price | $0.00 | $0.00 | $0.00 |
| Output price | — not charged | — not charged | — not charged |
| Tool calling | Supported | Supported | Supported |
| JSON mode | Supported | Supported | Supported |
| Vision input | Not supported | Not supported | Supported |
| Open weights | Not supported | Not supported | Not supported |
| Prompt caching | Not supported | Supported | Supported |
Best value in each row is highlighted. Illustrative placeholder data.
Provider information
View 01.AI →01.AI · 零一万物 · Beijing, China · est. 2023
AI focused on extracting maximum capability per parameter, its Yi models punched far above their size class in bilingual benchmarks. The lab has since concentrated on the fast, inexpensive Yi-Lightning line for production workloads.
Recent releases
Documentation
Frequently asked questions
Input is billed at $0.00 per 1M tokens, and there is no separate output charge. Every figure on this page is an illustrative placeholder.