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Relace vs StreamLake
StreamLake sells KAT-Coder, a proprietary agentic coding model; Relace sells the fast apply and search models that coding agents call as tools. A main model and its helpers.
By The Subconscious Team · Updated
Relace vs StreamLake: key differences
StreamLake and Relace both serve coding agents from different layers. StreamLake, Kuaishou's AI cloud, sells KAT-Coder-Pro V2.5, a proprietary model that StreamLake says was trained with large-scale agentic RL to read issues, change files across a repo, run tests and fix its own errors. It plugs into Claude Code through a Claude-protocol proxy and sells per token or on a KwaiKAT Coding Plan. Relace does not write the code. It applies it, merging edit snippets at about 10,000 tokens per second, and adds agentic search and context compaction.
In one stack, KAT-Coder could plan and write changes while Relace merges them and pulls relevant code, which Relace says runs over 3x faster and cheaper than full rewrites by the big model. Data location may decide whether that pairing is allowed. StreamLake keeps data in China, and its pricing and docs lead with yuan, while Relace offers self-hosted deployment for enterprises that keep code in-house. Relace's apply model caps at 128K tokens, so very large files need a fallback.
What Relace and StreamLake do
Relace
Relace trains small, fast models that act as tools for coding agents. Its best-known product is Instant Apply: a frontier model writes a lazy edit snippet, and relace-apply-3 merges it into the original file at about 10,000 tokens per second with 128K tokens of input and output. Relace says this runs over 3x faster and cheaper than having the big model rewrite the file. It exposes both a REST endpoint and an OpenAI-compatible one, and the model is also listed on OpenRouter.
Example models: relace-apply-3, Relace agentic search
Full Relace profileStreamLake
StreamLake is the AI cloud brand of Kuaishou, the Chinese short-video company behind the Kling video models. It sells model-as-a-service inference and bare-metal compute to internet businesses, drawing on the infrastructure Kuaishou built to serve video at massive scale. Its developer site offers APIs, SDKs and integration guides aimed at taking teams from testing to production.
Example models: KAT-Coder-Pro V2.5, KAT-Coder-Air
Full StreamLake profileShould you choose Relace or StreamLake?
Relace
Choose Relace for
- Fast edit merges beside any main coding model
- Self-hosted tooling for proprietary code
- Parallel search over large repositories
StreamLake
Choose StreamLake for
- A main agentic coding model on a subscription plan
- Repository-level coding inside Claude Code
- Chinese businesses wanting domestic MaaS
Relace vs StreamLake at a glance
| Attribute | Relace | StreamLake |
|---|---|---|
| Model access | Specialist models | Proprietary coding models |
| Flagship models | relace-apply-3, agentic search | KAT-Coder-Pro V2.5, KAT-Coder-Air |
| Speed | ~10,000 tok/s apply | Unknown |
| Price | 3x+ cheaper than full rewrites | Per token or KwaiKAT Coding Plan |
| Customization | Unknown | Unknown |
| Deployment | Hosted API or self-hosted | MaaS API, bare metal |
| Long context | 128K max | Unknown |
Frequently asked questions
What is the difference between Relace and StreamLake?
StreamLake sells KAT-Coder, a proprietary agentic coding model; Relace sells the fast apply and search models that coding agents call as tools. A main model and its helpers.
When should I choose Relace over StreamLake?
Fast edit merges beside any main coding model; Self-hosted tooling for proprietary code; Parallel search over large repositories.
When should I choose StreamLake over Relace?
A main agentic coding model on a subscription plan; Repository-level coding inside Claude Code; Chinese businesses wanting domestic MaaS.
Is Relace or StreamLake cheaper?
Relace: 3x+ cheaper than full rewrites. StreamLake: Per token or KwaiKAT Coding Plan. The cheaper choice depends on the model and workload.
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