Google Meridian

Google Meridian is a free, open-source library for Bayesian marketing mix modeling and causal measurement. It is best suited to cross-functional teams with the technical capacity to build and interpret models. Its central strength is connecting channel measurement to budget decisions; the Scenario Planner depends on an accessible trained model.

Overview

Meridian estimates channel contribution, return on investment and incremental outcomes, and models response curves to inform budget allocation. Teams can use geo-level data for more granular media-effect estimates, incorporate business knowledge through priors, and add controls such as Google Query Volume to account for organic demand.

Open-source code and methodology papers support transparency and auditability. That makes Meridian a strong fit for teams that want to inspect and adapt their measurement approach, but a weaker fit for organizations looking for a managed, ready-to-run workflow.

It sits within Marketing Performance Management Software, with a particular focus on marketing measurement and allocation.

Key features

Measurement and budget planning

Meridian combines forecasting and ROI reporting with budget optimization and scenario planning. Teams can compare marketing allocations using modeled response curves, rather than treating channel contribution as the only decision input. Multi-currency support is useful for measurement across markets.

Geo analysis and calibration

Meridian supports geo-level data and causal estimates of marketing impact. Its companion GeoX project provides an open-source way to run publisher-agnostic geo experiments and use their results to calibrate models. Automated calibration and expanded model health diagnostics give measurement teams additional ways to connect experimental results with model estimates.

Reach, frequency and data inputs

Reach and frequency modeling supports analysis of video and search query volume data, helping teams account for those measures and organic demand in their models. Google's MMM Data Platform helps gather brand campaign data across Google Ads and Display & Video 360, and provides reach and frequency data for YouTube. This Google data support is useful for teams working with those channels, while GeoX's publisher-agnostic approach broadens experimental calibration beyond a single publisher.

Scenario Planner and Meridian Studio

The Scenario Planner notebook requires at least one trained model saved in Google Drive or Google Cloud Storage that it can access. That dependency is material: teams cannot generate a report from an empty setup, and must first build and store a model in an accessible location.

Meridian Studio is the managed alternative for teams that need a cloud-based workflow. Its Google Cloud-powered platform supports building, managing and customizing models, can run up to hundreds simultaneously, and is described as a secure, UI-based environment with governed and automated workflows. It better suits measurement teams operating at scale than those who need only the open-source library.

Pricing

Meridian Open-Source: free. It is free for anyone to use and includes the open-source MMM library. The free plan is the product's core offering, making it appropriate for teams able to supply their own modeling workflow and infrastructure. Meridian Studio is an enterprise option; contact Google for pricing.

The tradeoff is operational rather than a stated subscription cap: the Scenario Planner needs a trained model accessible in Drive or Cloud Storage, and teams must build and analyze models themselves unless they choose the managed Studio platform.

Platforms

Meridian supports API, Linux, macOS, self-hosted and web use. That range accommodates technical teams working in their own environments as well as notebook-based workflows, but it does not turn the library into a managed service by itself.

Who it's for

Google positions Meridian for cross-functional measurement teams, including marketing analysts, business users, data scientists and technical practitioners. It is most compelling when those roles can collaborate on model inputs, interpretation and budget decisions. Teams without capacity to build and maintain models, or that need a governed interface for many concurrent models, should consider Meridian Studio or a different managed platform.

Pros and cons

Open and auditable: source code and methodology papers let technical teams examine the modeling approach.

Connects measurement to decisions: ROI reporting, forecasting, response curves and scenario planning support allocation work, not just retrospective reporting.

Experimental calibration: GeoX provides a publisher-agnostic route to use geo-experiment results in MMM calibration.

Setup dependency: Scenario Planner reports require a trained model already stored where the notebook can access it.

Technical ownership: the open-source library suits teams with modeling capability better than organizations seeking a turnkey managed workflow.

Alternatives

Robyn is another free option with a free plan and API, Linux, macOS, self-hosted and Windows platforms; consider it when Windows support is important.

Keen is a paid option with a free trial and API and web platforms; it may suit readers who prefer to evaluate a paid product before committing.

Sellforte offers a paid Incrementality Testing plan at $1,900 a month, based on average monthly media spend of $300,000, with digital media, geo lift, conversion lift and A/B experiments, and incremental sales and iROAS. Choose it when those testing methods and a defined spend basis match the need.

Etropo Budget Buddy has an Essential Plan at $89 a month, billed per month, for five team members, up to 15 line items and up to three currencies, with budget dashboards, actual spend analysis and Google Sheets integration. It is a more focused fit for teams whose priority is budget tracking within those limits rather than open-source MMM.

LiftLab is a paid enterprise marketing measurement platform with custom pricing and subscription terms specified in an Order Form; consider it when an enterprise platform is the priority.

Planful is a paid API and web option with pricing tailored to company size, user count and selected modules; it may fit buyers who need pricing shaped around those factors.

Revlo Marketing is a paid alternative.

Paramark is a paid web option. Its Essentials plan costs $100,000 a year, billed annually as one invoice, and includes one Marketing Mix Model, unlimited channels, unlimited incrementality tests per year and unlimited users. It is worth considering when those included model and testing allowances fit the budget and requirements.

Verdict

Choose Meridian if your measurement team wants an auditable, free framework that links causal channel estimates to forecasting and budget planning, and can build and maintain its own models. Look elsewhere if you need a managed workflow without the trained-model prerequisite; Meridian Studio is the more direct Google option for teams that need governed operation and the capacity to run models at scale.