OpenX is an independent supply-side platform (SSP) and programmatic ad exchange headquartered in Pasadena, California, founded in 2008. OpenX connects publishers and app developers to advertiser demand through a real-time marketplace that runs OpenRTB-based auctions across display, video, CTV, native, and mobile inventory. Its product suite is organized around the OpenX Exchange (the core marketplace), OpenXSelect (curation, deal creation, and supply-path targeting), OpenXBuild (real-time bidstream enrichment, auction insights, and identity resolution), and OpenXControl (publisher yield management and demand routing). OpenX runs five developer surfaces on api.openx.com: a REST Platform API (v4) for accounts, inventory, orders, deals, and targeting; a Reporting API for asynchronous CSV report generation across 41 dimensions and 9 metrics; an OpenXSelect GraphQL API for audiences, segments, deals, and bidder objects; an OpenXBuild Real-Time Bidstream API that a partner implements as a containerized enrichment service (HTTP POST /openrtb25 plus an IAB Agentic RTB Framework gRPC RTBExtensionPoint); and an undocumented but live remote MCP server. Authentication is OAuth 2.0 authorization-code with PKCE fronted by Google Cloud Identity Platform, published through real OIDC and RFC 9728 discovery documents, with a separate 90-day x-apikey credential for the GraphQL API. OpenX publishes no OpenAPI, no Postman collection, no status page, no pricing, and no security.txt, and its documentation site currently renders as a broken single-page-app shell whose underlying content survives only as a JSON search index. The company is a major contributor to the Prebid.org header-bidding ecosystem and maintains a large GitHub organization, though its first-party API client libraries were last released to a package registry in 2021 and still target a legacy OAuth 1.0 login host that now returns HTTP 502. The business model is transaction-fee based, and API access requires an active OpenX account and BD/account-management onboarding rather than self-service signup.
OpenX publishes 5 APIs on the APIs.io network. Tagged areas include Advertising, Programmatic Advertising, Ad Exchange, Supply Side Platform, and Real-Time Bidding.
OpenX’s developer surface includes documentation, API reference, getting-started guide, support, changelog, authentication, sandbox, and 53 more developer resources.
Regulatory Posture applies to this provider. Its tags matched the
Horizontal (data, software, accessibility, platform) regime, so
Regulatory Posture carries 15 points of the composite.
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Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for
this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero:
never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and
several others — scorable at all.
The six quality facets above are damped to 85 points between them,
because the conditional facet above carries the other
15. That is why each facet's contribution is shown against a damped
maximum: raising a quality facet moves the composite by 85% of its nominal
weight, not 100%. The full arithmetic is at apis.io/rating/.
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Asynchronous reporting API for authorized OpenX publishers. POST generateReport with dimensions, metrics, filters, reportType (HOURLY|DAILY) and an ISO-8601 date range returns a...
GraphQL API (BETA) for the OpenXSelect curation platform — query providers, segments, audiences, deals and packages, and mutate audiences (create/update/archive/activate), deals...
Live remote Model Context Protocol server at https://api.openx.com/mcp. Discovered by probe, not by documentation — OpenX does not mention MCP anywhere in its published docs, bu...
An inverted API — OpenX is the caller. A partner implements an enrichment service that OpenX hosts as a container inside its own Kubernetes namespace and calls in the auction pa...
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