Nisshi

Nisshi (formerly Tansu) is an open-source (Apache-2.0), Rust-built, Apache Kafka compatible message broker that stores data in S3, PostgreSQL, SQLite/libSQL or memory and can write schema-validated topics (JSON Schema, Avro, Protocol Buffers) as Apache Iceberg or Delta Lake tables. Its surface is the Kafka wire protocol rather than an HTTP API, and no OpenAPI, AsyncAPI or GraphQL contract is published. The project has been renamed Nisshi (README: 'Nisshi (nee Tansu)'); github.com/tansu-io/tansu redirects to github.com/nisshi-io/nisshi and tansu.io no longer resolves in DNS.

Nisshi is profiled on the APIs.io network. Tagged areas include Company, Kafka, Message Broker, Streaming, and Open Source.

Nisshi’s developer surface includes documentation and 6 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

4.9/100 minimal ▬ flat Agent 0/100 human only Heartbeat 56/100 alive Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

0 APIs

Company Kafka Message Broker Streaming Open Source Apache Iceberg Delta Lake Rust

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 4.9/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 2.0 / 17

Access Clarity 0.0 / 17

Operational Transparency 0.3 / 11

Contract Governance 0.0 / 10

Discoverability 3.8 / 9

Regulatory Posture 0.0 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes

13 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 0.0 — up to +25.0 composite points
Access Clarity scores 0.0 — up to +20.0 composite points
Developer Ergonomics scores 11.9 — up to +17.6 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/nisshi/apis.yml: open an issue on github.com/api-evangelist/nisshi to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 2

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Apache Iceberg

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

Delta Lake

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Build 4

SDKs, sample code, and the tooling you integrate with

SDKs

SDKs

Packages

Packages

GitHubOrganization

GitHubOrganization

SourceCode

SourceCode

Company 1

The organization behind the API

Website

Website

Other 1

Properties that don't map to a standard resource type

Hosts

Hosts

Source (apis.yml)

aid: nisshi
name: Nisshi
description: 'Nisshi (formerly Tansu) is an open-source (Apache-2.0), Rust-built, Apache Kafka compatible message broker that
  stores data in S3, PostgreSQL, SQLite/libSQL or memory and can write schema-validated topics (JSON Schema, Avro, Protocol
  Buffers) as Apache Iceberg or Delta Lake tables. Its surface is the Kafka wire protocol rather than an HTTP API, and no
  OpenAPI, AsyncAPI or GraphQL contract is published. The project has been renamed Nisshi (README: ''Nisshi (nee Tansu)'');
  github.com/tansu-io/tansu redirects to github.com/nisshi-io/nisshi and tansu.io no longer resolves in DNS.'
url: https://raw.githubusercontent.com/api-evangelist/nisshi/refs/heads/main/apis.yml
x-type: company
x-source: harvest:market-gap:streaming-kafka
x-tier: profiled
x-tier-reason: 'enrichment pass 2026-10-13 (local-v5; was harvest); minimal 2026-10-14: Kafka-wire-protocol broker, no published
  HTTP/OpenAPI/AsyncAPI contract, 0 operations'
x-aliases:
- tansu
x-renamed-from: tansu
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  probe_state: unreadable
  source: []
  generated: '2026-11-06'
  method: derived
specificationVersion: '0.20'
created: '2026-10-13'
modified: '2026-10-14'
tags:
- Company
- Kafka
- Message Broker
- Streaming
- Open Source
- Apache Iceberg
- Delta Lake
- Rust
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Hosts
  url: hosts/nisshi-hosts.yml
- type: SDKs
  url: packages/nisshi-packages.yml
- type: Packages
  url: packages/nisshi-packages.yml
- type: Website
  url: https://nisshi.io
- type: Documentation
  url: https://docs.nisshi.io
- type: GitHubOrganization
  url: https://github.com/nisshi-io
- type: SourceCode
  url: https://github.com/nisshi-io/nisshi
apis: []
x-coverage:
  state: unreadable
  reason: no-machine-readable-spec
  detail: Tansu is a Kafka-wire-protocol broker with no published HTTP contract, its tansu.io site no longer resolves in DNS,
    and the repo now redirects to the renamed Nisshi project (github.com/nisshi-io/nisshi).
  evidence:
  - url: https://tansu.io
    status: 0
  - url: https://github.com/tansu-io/tansu
    status: 200
  checked: '2026-10-13'
x-enrichment:
  date: '2026-10-13'
  status: minimal
  artifacts_added: 2
  pass: local-v5

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