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Head to head · FHIR servers · October 2026 research run

Particle Health vs Terra API

Terra API scores 65.9 (B) on agent readiness against Particle Health's 48.6 (D), and leads in every scored category. Both do fhir servers.

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

Particle HealthParticle Health, Inc. · HTTP API D48.6/100#867 of 1076 Terra APITerra Enabling Developers Inc. · HTTP API B65.9/100#327 of 1076

Which one, for what

Particle Health D

Best for US providers, payers and digital health companies that need a patient's network records as FHIR or flat data, and care-event alerts.

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

Watch for

Credentials come from a Particle representative, and the 'play for free' sign-up domain did not resolve

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

  • Reliability, 67 against 58
  • Schema & documentation, 89 against 69
  • Agent ergonomics, 78 against 53
  • Security & auth, 65 against 57
  • Payments & pricing, 20 against 5
  • Maintenance & community, 75 against 27
  • Transparency & trust, 56 against 48

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

Score by category

CategoryWeight this runParticle HealthTerra APIEdge
Reliability16%205867Terra API +9
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26989Terra API +20
Agent ergonomics13%16.25378Terra API +25
Security & auth14%17.55765Terra API +8
Payments & pricing10%12.5520Terra API +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.82775Terra API +48
Transparency & trust7%8.84856Terra API +8
Negative events≤1500
TotalD 48.6/100B 65.9/100

Facts side by side

FactParticle HealthTerra API
KindHTTP APIHTTP API
VendorParticle Health, Inc.Terra Enabling Developers Inc.
Hosted endpointno (local only)https://access.tryterra.co/api/v2/mcp/<user_id>
TransportsHTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingPaidPay per use
x402nono
LicenceProprietary service under customer agreements. The public terms of use (effective 15 October 2020) cover the website onlyProprietary service under Terra's terms of service. The OpenAPI specs repository is Apache 2.0
Tools exposednone6
Read-only variant documentednono
llms.txtyesyes
Last releasenone2026-10-13
Terms last updated2020-10-152026-05-01
Privacy policy last updated2026-07-292023-04-20
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingnot found in the textyes
Terms or service can change without noticeyesyes
Arbitration or class-action waiveryesyes
Popularitynone13k npm/wk, 11k PyPI/wk

Verdicts

Particle Health

Particle queries Carequality, CommonWell, eHealth Exchange and state HIEs for a patient and returns FHIR R4B, flat data or C-CDA, with project-scoped 60-minute tokens and OpenAPI fragments per endpoint. Credentials come through a representative, the free sign-up link was dead on 14 October 2026, and rate limits, SLA and changelog are unpublished.

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.

Before you call either

Particle Health

  1. Pass projects/<project_id> as the scope when requesting a token, and request a new one every 60 minutes
  2. Poll Get Query Status, or wait for the query-complete webhook, before reading FHIR or flat data
  3. Back off on 429, since limits change with system load
  4. Pass continuation tokens back verbatim when paging
  5. Use the published synthetic patients in sandbox, and stay under 500 queries a day

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

Questions

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

Terra API scores 65.9 (B) on agent readiness against Particle Health's 48.6 (D), and leads in every scored category.

Do Particle Health and Terra API need an API key?

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

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

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

Other comparisons with Particle Health or Terra API

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