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Head to head · Patient consent · October 2026 research run

Terra API vs 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. Both do patient consent.

Best health record and wellness data APIs for AI agents · All 63 health comparisons

Terra APITerra Enabling Developers Inc. · HTTP API B65.9/100#327 of 1076 Zus HealthZus Health, Inc. · HTTP API C56.6/100#669 of 1076

Which one, for what

Terra API B

Best 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

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

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

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

Score by category

CategoryWeight this runTerra APIZus HealthEdge
Reliability16%206766Terra API +1
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28977Terra API +12
Agent ergonomics13%16.27867Terra API +11
Security & auth14%17.56549Terra API +16
Payments & pricing10%12.5205Terra API +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87564Terra API +11
Transparency & trust7%8.85659Zus Health +3
Negative events≤1500
TotalB 65.9/100C 56.6/100

Facts side by side

FactTerra APIZus Health
KindHTTP APIHTTP API
VendorTerra Enabling Developers Inc.Zus Health, Inc.
Hosted endpointhttps://access.tryterra.co/api/v2/mcp/<user_id>no (local only)
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyOAuth
PricingPay per usePaid
x402nono
LicenceProprietary service under Terra's terms of service. The OpenAPI specs repository is Apache 2.0Proprietary service under the Zus Builder Terms of Service (last updated 11 March 2025), the Developer Sandbox Terms and the Zus Business Associate Addendum
Tools exposed6none
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-132026-10-14
Terms last updated2026-05-012025-03-11
Privacy policy last updated2023-04-202026-06-24
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticeyesnot found in the text
Arbitration or class-action waiveryesnot found in the text
Popularity13k npm/wk, 11k PyPI/wknone

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.

Other comparisons with Terra API or Zus Health

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