# Horizon Horizon declares [4 subprocessors](https://thirdpartyindex.com/vendors/horizon#subprocessors) in [its subprocessor list](https://trust.usehorizon.ai/subprocessors), which we last checked on 2026-10-12 ([evidence](https://thirdpartyindex.com/evidence/81266)). They include [Amazon Web Services](https://thirdpartyindex.com/vendors/amazon-web-services), [Google Cloud](https://thirdpartyindex.com/vendors/google-cloud) and [OpenAI](https://thirdpartyindex.com/vendors/openai). No published changes since we first read it on 2026-10-11. Horizon (usehorizon.ai): subprocessors, data processing agreement, security documents and changes, as monitored by Third Party Index. - Page: https://thirdpartyindex.com/vendors/horizon - Documents last verified: 2026-10-12 - Transparency rating: 67/100 (how much it publishes, not how secure it is): Subprocessor list 30/30; Processing locations 8/8; Purposes 2/7 (partial); Data processing addendum 0/12 (not found); Trust center 8/8; Privacy policy 6/6; security.txt 0/6 (not found); Security page 0/5 (not found); Status page 5/5; Vulnerability disclosure 0/5 (not found); Pages still reachable 8/8 - Supply chain: relies on 4 tracked vendors directly, 58 within two hops, 200 within three; 0 tracked vendors rely on it directly, 0 within two hops, 0 within three - Cite as: Horizon, Third Party Index, https://thirdpartyindex.com/vendors/horizon (data CC BY 4.0) ## Documents | Document | URL | Last verified | Last changed | |---|---|---|---| | Trust center | https://trust.usehorizon.ai/ | 2026-10-12 | 2026-10-12 | | Subprocessor list | https://trust.usehorizon.ai/subprocessors | 2026-10-12 | 2026-10-11 | | Privacy policy | https://usehorizon.ai/privacy | 2026-10-12 | 2026-10-11 | | Terms | https://usehorizon.ai/terms | 2026-10-12 | 2026-10-11 | | Status page | https://status.usehorizon.ai/ | 2026-10-12 | 2026-10-11 | ## Subprocessors (4) As its own list states them. | Subprocessor | Purpose | Location | Listed since | |---|---|---|---| | [Amazon Web Services](https://thirdpartyindex.com/vendors/amazon-web-services.md) | — | Cloud provider | 2026-10-11 | | [Google Workspace](https://thirdpartyindex.com/vendors/google-cloud.md) | — | Identity provider | 2026-10-11 | | [OpenAI](https://thirdpartyindex.com/vendors/openai.md) (AI model provider: OpenAI) | — | Engineering | 2026-10-11 | | [Vanta](https://thirdpartyindex.com/vendors/vanta.md) | Continuous security and compliance monitoring | Security | 2026-10-11 | Read from ([evidence](https://thirdpartyindex.com/evidence/81266)). CSV: https://thirdpartyindex.com/vendors/horizon/subprocessors.csv AI model providers (or a cloud provider's AI model service) among these entries: 1. All vendors that list one: https://thirdpartyindex.com/ai ## Compliance As its trust center lists them. - Audited: SOC 2, ISO/IEC 27001 ([evidence](https://thirdpartyindex.com/evidence/81269)) - Claimed: GDPR ([evidence](https://thirdpartyindex.com/evidence/81269)) ## Subprocessor of (0) No tracked vendor lists it. ## Incidents reported by Horizon's subprocessors Incidents reported in the last 30 days on their own status pages by 2 vendors Horizon lists as subprocessors. A subprocessor list names a company, not the service an incident touched. - 2026-10-09: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Workspace admins may be unable to manage plugins (major) - 2026-10-09: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Some ChatGPT content may be unavailable on Android (major) - 2026-10-09: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Delayed Costs data in the Compliance API (minor) - 2026-10-08: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Some APAC users are seeing errors in ChatGPT Work, conversations, and GPTs. (minor) - 2026-10-07: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors with GPT-5.6 Instant in FedRAMP workspaces (minor) - 2026-10-07: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Degraded performance in Codex and Work mode: Dot turn failures, delayed responses, and reduced proactivity (minor) - 2026-10-07: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Dot in Codex may fail to create new threads (minor) - 2026-10-07: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Unable to create new ChatGPT Work threads in latest version of desktop app (major) - 2026-10-07: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Workspace Agents Degraded and Responses Impacted (minor) - 2026-10-06: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Computer Use Is Experiencing Issues (minor) - 2026-10-06: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Errors processing large PDFs in the Responses API (minor) - 2026-10-06: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated error rates in ChatGPT Go conversations (minor) - 2026-10-06: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors affecting multiple products including ChatGPT (conversations), Image generations, Spaces and Pages, API rehydration, and Dots. (minor) - 2026-10-06: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors in API Platform login and administration APIs. (minor) - 2026-10-05: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated error rates in Codex Cloud (no impact stated) - 2026-10-05: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors in ChatGPT conversations (minor) - 2026-10-05: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Admin Console Intermittently Inaccessible (no impact stated) - 2026-10-05: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Issues saving and editing Pages (minor) - 2026-10-05: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated Work Mode errors (minor) - 2026-10-02: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Issues with data analysis and file creation in ChatGPT (minor) - 2026-10-01: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Issues with login, signup, and ads (major) - 2026-09-30: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated latency for some API requests (minor) - 2026-09-30: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated error rates for ChatGPT Pro and Plus users (minor) - 2026-09-30: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors in ChatGPT Space Pages (minor) - 2026-09-29: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors across ChatGPT, Codex, and the API including the Agents API (minor) - 2026-09-29: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Support available via email (no impact stated) - 2026-09-25: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Issues with Codex (critical) - 2026-09-24: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated Error Rates on GPT-6 Astra Pro (no impact stated) - 2026-09-23: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Mobile users unable to see Work Mode and the Model Picker (minor) - 2026-09-23: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated Error Rates for ChatGPT across Plus and Pro plans. (minor) - 2026-09-22: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated Error Rates for ChatGPT Work, across Plus, Pro, Business, Enterprise and Education plans. (minor) - 2026-09-22: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Increased error rate for Plus and Pro users. (minor) - 2026-09-18: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported SSO sign-in and SCIM provisioning issues (no impact stated) - 2026-09-18: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Overbilling for OpenAI-hosted containers in the Agent API (no impact stated) - 2026-09-18: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Delayed support responses (no impact stated) - 2026-09-17: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported We are seeing elevated error rates across API models (minor) - 2026-09-17: [Vanta](https://thirdpartyindex.com/vendors/vanta#status), which Horizon lists as a subprocessor, reported Vendor assessment product test failures (minor) - 2026-09-17: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors affecting ChatGPT Work mode (major) - 2026-09-16: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors in ChatGPT Work (minor) - 2026-09-15: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors with gpt-image-2.5-flare (major) - 2026-09-15: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Ads Manager login issues (minor) - 2026-09-15: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors from GPT-5.6 and GPT-5.6 Instant on paid plans (minor) - 2026-09-14: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Degraded Performance affecting Agents API (no impact stated) - 2026-09-14: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors affecting Work Mode in ChatGPT (minor) - 2026-09-14: [Vanta](https://thirdpartyindex.com/vendors/vanta#status), which Horizon lists as a subprocessor, reported Some Vanta AI features are unavailable (major) - 2026-09-14: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated error rates for Codex and ChatGPT Work (no impact stated) - 2026-09-13: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Elevated errors for ChatGPT users in Europe (minor) - 2026-09-13: [OpenAI](https://thirdpartyindex.com/vendors/openai#status), which Horizon lists as a subprocessor, reported Codex GitHub Review and Pull Request Failures (minor) The subprocessor list as we read it on any date: https://thirdpartyindex.com/labs/time-machine/horizon --- Third Party Index (https://thirdpartyindex.com) monitors vendors' public security and privacy documents and keeps each version as evidence. Data CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/); vendors' own documents are theirs. API: https://thirdpartyindex.com/api