# Systems Engineering, Inc. (SEI)

**Canonical:** https://apis.io/providers/seisystems/  
**Website:** https://www.seisystems.com/  
**APIs profiled:** 1

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.

## Kin Score — 5.4 / 100 (minimal)

Scored 2026-11-06 under rubric 0.27.0. Trend: flat (-1.4 from 6.8).

| Facet | Score |
|---|---|
| Discoverability | 53.6 |
| Contract Quality | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 7.1 |
| Access Clarity | 0.0 |

Regulatory layer — **Horizontal (data, software, accessibility, platform)**: 5.9 (matched via fallback).

## Agent readiness — 0.0 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |
| Delegated Identity | no |
| Protected Resource Metadata | no |
| Dynamic Client Registration | no |
| Agentic Commerce | no |
| Pagination Ratio | na |
| Operation Distinctiveness | na |
| MCP Tool Quality | na |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## APIs (1)

- **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 (1)

- **Seisystems Domain Security** — TLSv1.3

## Tags

Company, Real Estate, MLS, RESO, RESO Web API, RETS, Property Data

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/seisystems/). Scores are computed from the provider's own public artifacts under a published rubric.