kus
Kus (Knowledge Understanding & Summarization) is a knowledge API for small or local language models. It searches trusted sources and returns answers with citations, and it can mix public web knowledge with your own private documents.
Give any model answers it can back up.
One API call searches trusted sources and returns an answer with citations, so a small or local model answers from real evidence.
Open KusWhat you get
Cited, verifiable answers
Kus searches trusted sources and returns citations you can check.
Brings in your own docs
Add private documents next to public web knowledge, kept separate for each API key.
Answers from evidence
Answers come from retrieved sources, so even a small model has something real to stand on.
71% to 92% on a small model
On 48 hard-to-recall technical facts, Qwen3 1.7B got 34 right on its own and 44 with Kus. Kus fixed 11 answers and broke 1. Our own questions, one model, October 2026.
Drop-in simple
One endpoint and a key. It works next to any model, in any stack.
See it in action
A real question, typed and sent to the live Kus from a test account.
A support chatbot running on a small model gets a policy question it can't answer from memory.
- 1
The model sends the question to Kus.
- 2
Kus searches trusted sources, plus the business's own private documents if any are connected.
- 3
It returns a grounded answer with citations, which the small model can repeat correctly and back up.
One request, a grounded answer
curl -X POST https://kus-api.26io.com/api/query \
-H "X-API-Key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"query": "What changed in the latest release of Next.js?",
"return_answer": true,
"return_chunks": true
}'Returns the grounded answer plus retrieval details: which domains it drew from, whether the response came from cache, and how long it took.
Three steps to get going
- 1
Call one endpoint
Send a question with your API key. It works alongside any model you already use.
- 2
Kus does the work
It searches trusted sources and keeps the strongest evidence.
- 3
Get cited answers
You get a grounded answer with citations, drawn from public web knowledge and your private documents.
Questions about Kus
What is Kus?
Kus is an API from 26io Techlab that helps small or local language models answer reliably. It searches trusted sources, keeps the strongest evidence, and returns an answer with citations that can be checked.
Does Kus make small models more accurate?
In 26io Techlab's own test in October 2026, a small open model, Qwen3 1.7B, answered 48 hard-to-recall technical questions such as default port numbers, RFC numbers, release years and physical constants. On its own it got 34 right (71%). With Kus it got 44 right (92%): Kus fixed 11 answers and turned 1 correct answer into a wrong one. The questions were written by 26io Techlab and graded automatically against known answers, using one model in one run.
Can Kus use an organization's own documents?
Yes. Kus can combine an organization's private documents with public web knowledge. Documents are kept separate for each API key, so one customer's documents never appear in another customer's answers.
How fast are answers from Kus?
Questions Kus has already answered are served from its cache, without a fresh search, so they come back faster than new ones. A new question takes longer, because Kus first searches trusted sources and weighs the evidence before answering.
Where is the Kus API documentation?
Kus's public API reference is published at https://kus.26io.com/docs.
What are io credits?
io credits are the free monthly balance on a 26io account. One balance covers Evi, Kus and Revmosys. Every account gets 500 io credits a month, and once they run out you can refill once for 250 more. New accounts get 100 credits for their first 7 days. Each product shows the balance and a refill button. There is nothing to pay and no card to add.
Is Kus free to use?
Yes. Kus is free with a 26io account. Each question uses io credits from the same monthly balance as Evi and Revmosys, and the Kus Usage page shows the balance.