Systems Engineering, Inc. (SEI)

Systems Engineering, Inc. (SEI) is a US multiple listing service (MLS) software vendor whose NAVICA product line serves REALTOR boards and associations: NAVICA MLS, NAVICA NEXT, Showing Manager, Mobile Plus and Client apps, Association Management System (AMS), STREAMline, Data Share, Tax/public-data and web solutions. For data access SEI operates both RETS and RESO Web API servers that meet RESO compliance requirements including the RESO Data Dictionary (RESO certification record T00000075); access requires an agreement between the board/MLS, the participating office, the third party and SEI, with monthly fees. Partner integrations (dotloop, zipLogix, CRS, Property Panorama) use SSO and per-listing integration. No public API reference, base URL or machine-readable contract is published.

Systems Engineering, Inc. (SEI) is listed with 1 API on the APIs.io network. Tagged areas include Company, Real Estate, MLS, RESO, and RESO Web API.

Systems Engineering, Inc. (SEI)’s developer surface includes documentation, support, and 5 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

5.4/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 API

Company Real Estate MLS RESO RESO Web API RETS Property Data

Kin Score

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

Composite quality — 5.4/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 1.2 / 17

Access Clarity 0.0 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.6 / 9

Regulatory Posture 0.9 / 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 7.1 — up to +18.6 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/seisystems/apis.yml: open an issue on github.com/api-evangelist/seisystems 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.

RESO Web API

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

RETS

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

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

NAVICA RESO Web API and RETS Data Feeds

RESO Web API (OData) and RETS servers delivering NAVICA MLS data conforming to the RESO Data Dictionary to licensed third parties under a board/MLS, office, vendor and SEI agree...

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Seisystems Domain Security

TLSv1.3

SECURITY

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Company 2

The organization behind the API

Website

Website

LinkedIn

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: seisystems
name: Systems Engineering, Inc. (SEI)
description: 'Systems Engineering, Inc. (SEI) is a US multiple listing service (MLS) software vendor whose NAVICA product
  line serves REALTOR boards and associations: NAVICA MLS, NAVICA NEXT, Showing Manager, Mobile Plus and Client apps, Association
  Management System (AMS), STREAMline, Data Share, Tax/public-data and web solutions. For data access SEI operates both RETS
  and RESO Web API servers that meet RESO compliance requirements including the RESO Data Dictionary (RESO certification record
  T00000075); access requires an agreement between the board/MLS, the participating office, the third party and SEI, with
  monthly fees. Partner integrations (dotloop, zipLogix, CRS, Property Panorama) use SSO and per-listing integration. No public
  API reference, base URL or machine-readable contract is published.'
url: https://raw.githubusercontent.com/api-evangelist/seisystems/refs/heads/main/apis.yml
x-type: company
x-source: harvest:gap-automotive-real-estate
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-13 (local-v5; was harvest)
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  probe_state: none
  source:
  - security
  generated: '2026-11-06'
  method: derived
specificationVersion: '0.20'
created: '2026-10-13'
modified: '2026-10-13'
tags:
- Company
- Real Estate
- MLS
- RESO
- RESO Web API
- RETS
- Property Data
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Hosts
  url: hosts/seisystems-hosts.yml
- type: Vendors
  url: vendors/seisystems-vendors.yml
- type: DomainSecurity
  url: security/seisystems-domain-security.yml
- type: Website
  url: https://www.seisystems.com/
- type: Documentation
  url: https://www.seisystems.com/data.html
- type: Support
  url: https://www.seisystems.com/contact.html
- type: LinkedIn
  url: https://www.linkedin.com/company/systems-engineering-incorporated
apis:
- aid: seisystems:navica-reso-web-api
  name: NAVICA RESO Web API and RETS Data Feeds
  description: RESO Web API (OData) and RETS servers delivering NAVICA MLS data conforming to the RESO Data Dictionary to
    licensed third parties under a board/MLS, office, vendor and SEI agreement with monthly fees. Endpoints are issued with
    the agreement; no public base URL is documented.
  humanURL: https://www.seisystems.com/data.html
  tags:
  - RESO Web API
  - RETS
  - MLS
  properties:
  - type: Documentation
    url: https://www.seisystems.com/data.html
x-coverage:
  state: none
  reason: no-developer-program
  method: derived
  generated: '2026-10-13'
  generator: derive-coverage.py (pre-flight evidence)
  detail: the company publishes no developer documentation host and no machine-readable contract on its own domain
  evidence:
  - url: https://www.seisystems.com/
    status: 200
x-enrichment:
  status: enriched
  pass: local-v5
  date: '2026-10-13'

Systems Engineering, Inc. (SEI) API — frequently asked questions

Does Systems Engineering, Inc. (SEI) have an API?

Yes. APIs.io lists 1 API from Systems Engineering, Inc. (SEI), including NAVICA RESO Web API and RETS Data Feeds.

Is the Systems Engineering, Inc. (SEI) API ready for AI agents?

Systems Engineering, Inc. (SEI) has a Kin Score of 5.4 out of 100 (minimal) and an Agent Readiness score of 0.0 (human-only), scored by API Evangelist on 2026-11-06.

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