# Terra API vs Zus Health

> Terra scores 65.9 (B) to Zus Health's 56.6 (C) for patient consent. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/terra-vs-zus-health
- Markdown: https://www.anchorterminal.com/compare/terra-vs-zus-health.md (~2,300 tokens)
- Slim: https://www.anchorterminal.com/compare/terra-vs-zus-health.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/terra-vs-zus-health.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-14

Terra API scores 65.9 (B) on agent readiness against Zus Health's 56.6 (C), and leads in 6 of 7 scored categories. Both do patient consent.

- Terra API: grade B, 65.9/100, rank #327 of 1076. Markdown https://www.anchorterminal.com/tools/terra.md · JSON https://www.anchorterminal.com/api/v1/tools/terra.json
- Zus Health: grade C, 56.6/100, rank #669 of 1076. Markdown https://www.anchorterminal.com/tools/zus-health.md · JSON https://www.anchorterminal.com/api/v1/tools/zus-health.json
- Best health record and wellness data APIs for AI agents: https://www.anchorterminal.com/best/health-data/index.md
- All 63 health comparisons: https://www.anchorterminal.com/compare/health-data/index.md

## Which one, for what

### Terra API (B)

Good for: A fitness, wellness, insurance or research product whose users connect consumer wearables and apps, and an agent that needs to read one user's sleep, activity or body data through MCP.

Ahead on:
- Schema & documentation, 89 against 77
- Agent ergonomics, 78 against 67
- Security & auth, 65 against 49
- Payments & pricing, 20 against 5
- Maintenance & community, 75 against 64

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: No free tier. Sign-up asks for a plan and billing details, and Quick Start starts at $499 a month with a 30-day money-back guarantee

### Zus Health (C)

Good for: US care organisations and digital health builders that want a shared, continuously refreshed patient profile in FHIR with EHR embedding.

Watch for: No public prices, and the sandbox is requested through a Google Form


## Score by category

| Category | Weight | Terra API | Zus Health | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 66 | Terra API +1 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 77 | Terra API +12 |
| Agent ergonomics | 13% (16.2 this run) | 78 | 67 | Terra API +11 |
| Security & auth | 14% (17.5 this run) | 65 | 49 | Terra API +16 |
| Payments & pricing | 10% (12.5 this run) | 20 | 5 | Terra API +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 75 | 64 | Terra API +11 |
| Transparency & trust | 7% (8.8 this run) | 56 | 59 | Zus Health +3 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **65.9 · B** | **56.6 · C** | |

## Facts side by side

| Fact | Terra API | Zus Health |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Terra Enabling Developers Inc. | Zus Health, Inc. |
| Hosted endpoint | `https://access.tryterra.co/api/v2/mcp/<user_id>` | no (local only) |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Pay per use | Paid |
| x402 | no | no |
| Licence | Proprietary service under Terra's terms of service. The OpenAPI specs repository is Apache 2.0 | Proprietary service under the Zus Builder Terms of Service (last updated 11 March 2025), the Developer Sandbox Terms and the Zus Business Associate Addendum |
| Tools exposed | 6 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-13 | 2026-10-14 |
| Terms last updated | 2026-05-01 | 2025-03-11 |
| Privacy policy last updated | 2023-04-20 | 2026-06-24 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 13k npm/wk, 11k PyPI/wk | none |

## Verdicts

**Terra API.** Graded on the Unified API and the Terra AI MCP server. A public OpenAPI 3.1 spec, llms.txt, per-user rate limits with Retry-After, and scoped admin tokens with approvals. Access starts at $499 a month with billing details at sign-up, the data API key has no scopes, and API key requests failed for 2 hours 38 minutes on 7 August 2026.

**Zus Health.** FHIR R4 over an aggregated patient profile drawn from CommonWell, Carequality, Surescripts, Quest and ADT networks, with published rate limits, a 99.5 per cent SLA and a dated changelog. Accounts and sandboxes are provisioned by Zus on request, with no public prices, no named security certification and no SDK.

## Before you call either

### Terra API

1. Send dev-id and x-api-key headers on every Unified API and Terra AI call. A missing header returns 401 problem+json
2. Keep each request window to 1,825 days or less and under 6,000 requested days per user an hour. On 429 with rule r2, wait Retry-After seconds
3. Pass either fields or select to Terra AI tools, never both and never neither, or the call fails with a validation error
4. Expect data by webhook after a user connects through the widget session. REST reads are for backfills and on-demand queries
5. Use the Read only access level for the admin MCP server unless a change is needed. The MCP level can read API keys

### Zus Health

1. Cache the access token for its hour. More than 200 token requests an hour per App Client returns 429
2. Request Patient History at most once per patient per 24 hours, and poll the job status endpoint
3. Use conditional create by identifier so a retried write doesn't duplicate a resource
4. Send `Zus-If-Match` with the resource's ETag on PUT and PATCH
5. Set `_count` up to 500 on searches, since the default page is 10

## Questions

### Which is better for AI agents, Terra API or Zus Health?

Terra API scores 65.9 (B) on agent readiness against Zus Health's 56.6 (C), and leads in 6 of 7 scored categories.

### Do Terra API and Zus Health need an API key?

Terra API takes an API key or an OAuth sign-in. Zus Health uses an OAuth sign-in.

### Can an agent call Terra API and Zus Health without installing anything?

Terra API has a hosted endpoint at https://access.tryterra.co/api/v2/mcp/<user_id>. No hosted endpoint is listed for Zus Health.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/terra-vs-zus-health.json, and with the fewest tokens: https://www.anchorterminal.com/compare/terra-vs-zus-health.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "terra", "b": "zus-health"}`. From a terminal: `anchor compare terra zus-health`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/terra.json and https://www.anchorterminal.com/api/v1/tools/zus-health.json

## Other comparisons with Terra API or Zus Health

- [1upHealth vs Terra API](https://www.anchorterminal.com/compare/1uphealth-vs-terra.md)
- [Aidbox vs Terra API](https://www.anchorterminal.com/compare/aidbox-vs-terra.md)
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- [Particle Health vs Zus Health](https://www.anchorterminal.com/compare/particle-health-vs-zus-health.md)
- [Medblocks vs Terra API](https://www.anchorterminal.com/compare/medblocks-vs-terra.md)
- [ROOK vs Zus Health](https://www.anchorterminal.com/compare/rook-vs-zus-health.md)
- [Validic Inform vs Zus Health](https://www.anchorterminal.com/compare/validic-vs-zus-health.md)
- [ROOK vs Terra API](https://www.anchorterminal.com/compare/rook-vs-terra.md)
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- [Redox vs Zus Health](https://www.anchorterminal.com/compare/redox-vs-zus-health.md)