AppLovin has asked a San Francisco court to stop Unity Technologies from using an in-app software kit to read information about the advertisements AppLovin wins, turning a four-week exchange of lawyers' letters into litigation even though Unity had already offered, in writing, to switch the tool off for AppLovin's MAX auctions.

In Short

AppLovin runs a big marketplace called MAX where ad companies bid to show ads inside mobile games, and Unity is one of the companies bidding there. AppLovin says a Unity tool sitting inside the same apps has been copying details about the ads AppLovin wins - the ad itself, who saw it, and how much money it made - and may be feeding that into Unity's own ad models. Unity says the tool only collects what app makers allow, that AppLovin's own tool does the same thing, and it offered to turn the tool off for MAX if AppLovin dropped its complaints. AppLovin refused that deal and asked a judge to force the switch-off instead, so if you make, sell or buy ads inside apps, the question of what one ad company's code may see about a rival's ads is now in front of a court.

Three filings in three days

The dispute moved from correspondence to formal proceedings in the space of three days. On September 27, 2026, AppLovin filed a demand for arbitration against Unity Technologies SF with JAMS, under reference number 5100004903. On September 28 it filed a petition in aid of arbitration in the Superior Court of California, County of San Francisco, relying on section 1281.8(b) of the state's Code of Civil Procedure, which lets a party to a pending arbitration ask a court for provisional relief when an eventual award "may be rendered ineffectual without provisional relief." The petition exists largely to obtain a case number; the court assigned CPF-26-520212, captioned AppLovin Corporation v. Unity Technologies SF.

The substantive papers followed on September 29. They comprise an ex parte application for a temporary restraining order and an order to show cause regarding a preliminary injunction, a declaration from AppLovin chief technology officer Xiaochuan "Giovanni" Ge, a declaration from Quinn Emanuel partner Joseph Sarles attaching twelve exhibits, a proposed order and a motion to seal. Much of the record is redacted. The contract between the two companies is sealed in full, and several paragraphs of the Ge declaration appear only as numbers followed by blank space.

What AppLovin wants is narrow on paper. The proposed order would bar Unity from "collecting, intercepting, extracting, using, or disclosing" what the filing calls AppLovin's Protected Data through the Ad Quality software development kit, or through any Unity software in which Ad Quality is embedded. It would require Unity to disable that collection within five business days and to modify the SDK within 30 days. AppLovin also asks the court to waive any bond, on the ground that Unity has said it can take the same steps anyway.

The hearing date is not consistent across sources. The application's caption, both declarations and the notice email Quinn Emanuel sent to Unity's counsel at 7:35 p.m. Pacific time on September 28 all set the hearing for September 30, 2026, at 11 a.m. Pacific, by videoconference, before Judge Joseph M. Quinn in Department 302. Digiday, which reported the filing on September 29, gave September 29 as the hearing date. The court's register of actions, retrieved on the morning of September 30 European time, listed no order on the application. A separate hearing on the sealing motion is set for October 23, 2026, at 9 a.m.

Unity is represented by Gary Bornstein and Jesse Weiss of Cravath, Swaine & Moore. According to the Sarles declaration, Bornstein replied to the notice that Unity intends to appear and oppose.

The arbitration demand pleads five causes of action: breach of contract, intentional interference with contractual relations, intentional interference with prospective economic advantage, misappropriation of trade secrets under the California Uniform Trade Secrets Act, and unfair competition under section 17200 of the California Business and Professions Code. It states an amount in controversy above $250,000 and seeks damages covering actual loss and unjust enrichment or, in the alternative, a reasonable royalty, plus an order requiring Unity to delete AppLovin's data "from its systems, datasets, and models." None of these allegations has been tested by a court or an arbitrator.

The contract that governs the auction

The two companies signed what the filings call the AppLovin Header Bidding Agreement on October 13, 2021. Unity's letters also refer to a mutual non-disclosure agreement dated April 27, 2021. The name reflects how in-app mediation borrowed the vocabulary of header bidding on the web: a mediation SDK inside the app offers each impression to several demand sources at once and awards it to the highest bid. According to the Ge declaration, the category includes AppLovin's MAX, Unity's LevelPlay, Google's AdMob, Digital Turbine's FairBid and Liftoff's Monetize.

Unity occupies several positions in that market simultaneously. It bids into MAX auctions through its ad network, Unity Ads, which the arbitration demand describes as powered by Unity's own AI recommendation engine, Vector. It operates LevelPlay, a mediation platform that competes with MAX. And it develops the Unity engine and Editor, which the demand says is "the platform on which a large share of the world's mobile games are built and run." AppLovin, for its part, runs MAX while also bidding into it through AppLovin Ads and its Axon engine. Each company is, in other words, both the auctioneer on its own platform and a bidder on the other's.

The agreement itself is under seal; AppLovin says section 6.4 obliges both parties to keep its terms confidential. The public filings describe provisions only in outline. According to the application, the contract grants Unity a limited license to use MAX for bidding on and buying impressions (section 2.2(a)), prohibits reverse engineering (section 2.1(d)(i)), and restricts Bid Request Data to use "solely to bid on Inventory made available via the Mediation Platform, and deliver the applicable Advertisement" while forbidding its use to "create or supplement profiles that relate to any individual End User" (section 2.4(c)). Section 6.2 governs confidential information. The demand quotes section 10.3, under which the parties agreed that "any unauthorized disclosure or use of a Party's Confidential Information or intellectual property would cause such Party irreparable harm for which monetary damages would be inadequate."

Three categories of auction data

The filings divide what flows through a MAX auction into three categories. Bid Request Data is what every invited bidder receives to decide whether to bid. Win and loss notifications go only to bidders that took part and, according to Ge, disclose "the minimum bid to win that single impression" but not the creative, the user, or the platform's cross-impression record. Served-Ad Data is the winning bidder's own record of what it showed: the creative, the advertiser, the associated identifiers, the user and device, and that user's clicks and engagement.

AppLovin defines its Protected Data as the combination of two things. The first is its Served-Ad Data wherever it wins, including in Unity's LevelPlay auctions and Google's AdMob auctions. The second is the record it derives from operating MAX, which the application lists as "the demand sources solicited, the price at which each impression cleared and the revenue attributable to it, the auction and impression identifiers, and the mediation waterfall." The company is careful about what it does not claim. "Unity may use its own Served-Ad Data as it chooses," the application states.

What AppLovin says Ad Quality does

Ad Quality is a Unity product marketed to app publishers as a way to monitor the advertisements appearing in their apps. According to AppLovin's filings, which cite Unity's own developer documentation throughout, it began as a standalone SDK that a publisher had to choose to install. Unity later packaged it into the Unity Ads SDK, which a publisher must integrate to receive Unity's bids in MAX. From LevelPlay SDK version 8.9.0, dated May 28, 2025 in Unity's changelog, it was bundled into LevelPlay too. The application quotes Unity's documentation: "Starting with version 8.9.0, Ad Quality is integrated into the LevelPlay SDK and automatically initializes when LevelPlay is implemented." AppLovin says the collection it objects to "has run since at least May 2025."

The technical description is the core of the case. According to the Ge declaration and the arbitration demand, Ad Quality downloads AppLovin-specific "connector" scripts, relies on a component that Unity's changelog names "SMLAppLovinBridge", interposes Unity code into AppLovin's listener callbacks, subscribes to the internal topic-based message channel that AppLovin's SDK uses to publish impression and revenue events, and injects Unity's JavaScript into the ads AppLovin renders. "Through its Ad Quality software, Unity reaches into AppLovin's in-memory ad objects, calls AppLovin's internal methods, and reads values from within AppLovin's SDK," Ge wrote in his declaration, signed on September 27. "This collection is not passive observation of anything an ordinary user could see." AppLovin also says Unity decides app by app whether and how much Ad Quality collects, through configuration pulled from Unity's servers at startup.

For each impression AppLovin wins, the demand lists the following as collected:

  • the creative assets, including video, image and icon files and the HTML and JavaScript of playable and end-card units, together with click-through destinations, advertiser identity, and creative, campaign and ad identifiers;
  • a publisher-assigned user identifier, a persistent Ad Quality installation identifier, a session counter, the Unity Ads installation identifier and a LevelPlay/ironSource shared user identifier, plus battery level, charging status and available and total device memory;
  • the revenue attributable to the impression, MAX ad unit, placement, impression and ad-instance identifiers, and "the mediation waterfall applied to the impression, including the participating networks, placement identifiers, and latencies";
  • the coordinates and timing of the user's most recent screen touch, captured, according to the demand, through "an invisible overlay in the publisher's application."

Unity's public Raw Data API documentation, as quoted in the application, exposes impression-level fields including user_id, ad_source, advertiser, creative_id, click and video_completed, a revenue field described as "The Revenue generated by the user (USD)", and imp_num, "Impression number in the sequence of a user." AppLovin says Unity's supported-sources page lists at least 25 ad sources, and that Meta Audience Network is the only one marked "Creative data is not supported." AppLovin reads that exception as evidence that Unity "understood the collection required the network's authorization." That is an inference, not a finding.

The most serious allegation is also the least supported in the public record. AppLovin claims, "on information and belief," that Unity feeds the collected data into models that bid against AppLovin, using "AppLovin's own output to train those models and to model AppLovin's ad decisions." Its argument rests on the shape of the data rather than on direct evidence of training: per-impression revenue, auction mechanics and cross-network user histories, the demand says, "have no bearing on ad quality or ad safety. They are a labeled training set describing what AppLovin served, to whom, what it earned, and to what effect."

A precedent from 2020

AppLovin reaches back six years for a comparison. The demand cites security researchers at Snyk, who reported in 2020 that Mintegral's advertising SDK, under a disclosure named SourMint, captured ad-click activity across thousands of apps, including activity on competing networks' ads. Mediation platforms and developers removed the SDK and Mintegral dropped the practice, according to the demand, which calls Ad Quality "the same thing but worse." It then offers an admission about its own restraint. AppLovin says it has not removed Unity from MAX, even though it considers Unity's collection more aggressive, "because cutting Unity off would harm the publishers who rely on MAX."

Unity's account

Unity's version appears in three letters from Bornstein, attached as exhibits to AppLovin's own filing. The first, dated September 4, rejects the premise outright. "Ad Quality does not collect any data from AppLovin," it states. According to Unity, the product collects data "only from its publishers' applications or end user devices, with express permission," is governed by Unity's contracts with those publishers, and has nothing to do with the header bidding agreement. Unity says Ad Quality and its predecessor, Soomla, collected data relating to MAX-mediated ads "since well before the parties entered into those agreements."

On activation, Unity's account is the reverse of AppLovin's. "For Unity's publisher clients using MAX, Ad Quality does nothing unless and until the publisher affirmatively switches it on," the letter says, adding that "enablement on MAX is currently on a small minority of ad impressions." Unity describes the bundling with the Unity Ads SDK as a convenience, "just as AppLovin bundles its own, far more intrusive, data-collection tool (which it calls Ad Review) with MAX." Unity also says it understands that AppLovin switches Ad Review on by default for all MAX publishers and collects data from impressions served by Unity Ads and every other network.

Unity's letters then turn the dispute into a question of market power. MAX, the September 4 letter says, "handles well over a majority of such auctions, whether measured by number of auctions or by share of wallet." It accuses AppLovin of self-preferencing and of "requiring publishers to use MAX in order to obtain access to AppLovin's ROAS product," and it cites the Virginia judgment against Google in United States v. Google LLC, the April 2025 ruling that Google monopolized publisher ad server and ad exchange markets. That comparison has limits Unity does not mention: the same court declined on September 2, 2026 to order the sale of Google's AdX, accepting behavioural remedies instead.

Unity also questions the timing. It says AppLovin acknowledged "nearly a year ago" that Ad Quality was integrated with one of Unity's ad networks and collected data for MAX-mediated ads. It links AppLovin's August demand to a quarter in which, by Unity's description, AppLovin "fell short of its guidance, was downgraded by analysts and saw an approximately 20% stock decline," while Unity's shares rose by a similar proportion. The filings contain no evidence for those market figures. On the record, AppLovin's second-quarter revenue reached $1.92 billion, up 53 percent, the slowest rate in its restated series. Unity's own second-quarter results, filed with the Securities and Exchange Commission on August 6, 2026, put Grow Solutions revenue at $389 million against $287 million a year earlier, a 35 percent increase, with what Unity calls Strategic Grow revenue up 63 percent to about $329 million.

There is a counter-grievance as well. Unity says AppLovin breaches Unity's Core Standards and Editor terms of service through "improper use of self-installed scoped registries and unauthorized distribution of unverified packages inside the Unity Editor." AppLovin answered on September 14 that those terms "bind Unity Editor licensees, not AppLovin," that it distributes the MAX SDK "through the same industry-standard mechanisms as other mediation platforms," and that it would consider "reasonable, industry-standard modifications."

Bundled is not the same as switched on

The sharpest factual disagreement is about defaults, and the two companies make mirror-image claims. AppLovin says Ad Quality ships inside Unity's SDKs by default and can be removed only through "the separate, non-obvious step of excluding it," while Unity says the product stays dormant on MAX until a publisher enables it. On Ad Review the positions reverse: AppLovin says its tool runs "only after a publisher activates Ad Review," and Unity says it is on for everyone.

These statements are not necessarily contradictory. Software can be present in an app and still require a server-side or publisher-side switch before it collects anything, and AppLovin's own description of remote configuration assumes exactly such a switch. What the public record does not show is how many MAX impressions Ad Quality actually observed. Unity says "a small minority." AppLovin says the collection "occurs in a number of the highest-volume applications transacting through MAX." Neither side has published a number, and the passages of the Ge declaration that might contain one are redacted.

The other disagreement concerns purpose. AppLovin states that it uses Ad Review data "solely to moderate ads - not to build profiles or to train AppLovin's models." Unity says Ad Review "collects the same data that Ad Quality collects, and far more, from more sources," and combines it with data from MAX and from Adjust, the attribution company AppLovin owns. The court is being asked to decide which tool is an ad-quality product and which is a data pipeline, on papers in which both companies claim to be the former.

Four weeks of letters

The correspondence shows how close the parties came to a private settlement, and why it failed.

AppLovin's opening letter, sent on August 21 by Alex Spiro of Quinn Emanuel to Unity's legal department and the office of its chief executive, set out what it described as a line AppLovin's CEO had already communicated: Unity "may use AppLovin's ad and ad-interaction data only at an aggregate, de-identified level." It demanded that Unity stop the collection and preserve evidence immediately and, within 14 days, notify publishers and certify in writing which data had been taken, over what period, and which models had been trained on it. It threatened "injunctive relief in a public forum."

Unity's September 4 reply rejected every demand. AppLovin wrote again on September 8, reading Unity's defence of its data use as an implicit admission that Unity trains models on data Ad Quality collects, and set a 72-hour deadline for Unity to stop collection, delete AppLovin data from systems and backups, produce a remediation plan for affected models and submit to a third-party audit.

Unity's position shifted on September 11. Bornstein wrote that Unity "sees no practical path to defend itself from AppLovin's unjustified accusations without jeopardizing a sizable portion of its ad network revenue," describing MAX as the platform "through which a sizable majority of all mobile ad traffic flows." Unity offered two steps: within five business days, tell publishers to stop using Ad Quality for MAX-mediated auctions, and within 30 days, release a Unity Ads SDK without Ad Quality. "By taking these actions, Unity considers the issues raised by AppLovin to be wholly resolved," the letter said.

AppLovin called that "a necessary first step" on September 14, but objected to Unity's decision to strip the feature entirely. "AppLovin did not ask Unity to remove Ad Quality entirely; we asked Unity to stop using the Ad Quality SDK to take AppLovin's data and to train its models on it," Spiro wrote. The letter set a 48-hour deadline and added new demands, among them an executive-level certification that Unity would never use AppLovin data for model training and prior sight of Unity's notice to publishers. AppLovin even proposed the wording: "The current Ad Quality feature will no longer be supported on MAX mediation as of [date]."

Unity's final letter, on September 16, went further on method but not on terms. It said Unity could switch off Ad Quality's collection in MAX-mediated auctions remotely, "including the Ad Quality deployment in ironSource Ads," so that "there will be no Unity products used with MAX that will have Ad Quality packaged with it." Data already collected would be deleted "in the ordinary course, in accordance with its generally applicable data retention policies." Unity refused to retrain or retire models, and refused to show AppLovin its publisher communications, while agreeing to send a "neutral, factual notice." It framed the whole offer as a response "for one reason and one reason only: AppLovin's anticompetitive threat to cut Unity off from the MAX platform," and made it "contingent on AppLovin's written confirmation that, by Unity doing so, it will fully resolve the issues raised by AppLovin." Any termination of the header bidding agreement, Unity warned, "would clearly be retaliatory and pretextual."

Why AppLovin went to court anyway

AppLovin gives three reasons for rejecting an offer that, on its face, delivered most of what the court is now being asked to order. The first is the release: Unity's commitment required AppLovin to treat the matter as closed, which in AppLovin's reading would abandon claims over data already collected and any models already trained. The second is enforceability. Without an order, AppLovin argues, Unity could switch collection back on remotely at any time, "a right that Unity expressly preserved." The public versions of the letters do not contain an explicit reservation of that kind; what Unity reserved was "all rights regarding AppLovin's past and current conduct," and the characterization is AppLovin's. The third is scope. Unity's offer covered MAX-mediated auctions only, leaving untouched any collection when AppLovin wins impressions through LevelPlay or AdMob.

The interim relief AppLovin seeks is narrower than its letters. It does not ask the court to order deletion or model remediation; those demands, the application says, are reserved for arbitration. Instead, it turns Unity's own concessions into its central argument. Because Unity has said it can disable collection on MAX within a working week and ship an SDK without Ad Quality within a month, AppLovin contends, an order requiring the same thing imposes no burden. "An erroneous grant costs Unity a pause in a data feed it has said it is willing and able to switch off," the application argues, while "an erroneous denial, by contrast, lets Unity continue to harm AppLovin unabated." It invokes the voluntary cessation doctrine, under which a defendant's promise to stop does not moot a request for an injunction when the conduct could resume.

The sealing motion adds a procedural twist. AppLovin relies on section 3426.5 of the California Civil Code, which it argues imposes a "mandatory confidentiality requirement" in actions brought for trade secret misappropriation. Much of what a reader would want to know, including the full text of the agreement and several paragraphs describing how AppLovin protects its data technically, is likely to stay out of public view.

Inconsistencies in the filings

The record contains several discrepancies beyond the hearing date. A footnote in the application says Unity's letters establish its ability "to ship a compliant SDK within five business days," but Unity's September 11 letter gave 30 days for a new Unity Ads SDK; the five-day figure related to notifying publishers and, later, to the remote switch-off. One passage of the application attributes the remote switch-off quotation to the September 11 letter, although it appears in the September 16 letter. The Sarles declaration describes the application as filed on September 30, while the court's file stamp reads September 29. And the sealing declaration lists Exhibit F as a September 8 letter, where the main Sarles declaration lists Exhibit F as the August 21 cease-and-desist and Exhibit G as the September 8 letter. None of these changes the substance of the dispute.

Money, data and the people in between

Both companies arrive in court during a period of heavy investment in AI-driven bidding. AppLovin reported first-quarter 2026 revenue of $1.84 billion and opened its Axon advertising platform to all advertisers in June. It has spent more than a year answering questions about its own data practices, from the short-seller reports of early 2025 that alleged unauthorized collection of third-party identifiers to a February 2026 defence of the Axon business model by chief executive Adam Foroughi. Unity has been turning its own gaming signals into products for advertisers, including an Audience Hub built with Optable covering 256 million monthly active US gamers. The ironSource Ads deployment of Ad Quality named in Unity's September 16 letter sits in a network from which, according to a Unity investor update dated March 26, 2026, the company expected minimal revenue after the first quarter of 2026.

The measurement layer underneath both firms has been reorganised for similar reasons. In June 2026, Google, Meta, Moloco and Unity took minority stakes in AppsFlyer at a $2.7 billion valuation, under terms barring preferential treatment for investors. AppLovin owns Adjust, a rival mobile measurement partner, a fact Unity raises in its September 4 letter as evidence that AppLovin itself combines data from several positions in the stack.

Why this matters for the marketing community

Most of the people affected by this dispute are not parties to it. AppLovin's filings describe publishers as unwitting participants: "The publishers are not the wrongdoers here," the demand states, even as it argues that a publisher that lets Ad Quality run alongside MAX breaches AppLovin's terms. AppLovin's Policies for Publishers state that "All pricing information, including revenue share or any information that would allow a third party to ascertain revenue share, constitutes AppLovin Confidential Information." Unity, for its part, says the collection happens with those same publishers' express permission. A studio running both SDKs, which the demand notes is common, is therefore caught between two contracts that describe the same data differently.

The practical consequence is software updates. Unity's September offer involved a new Unity Ads SDK without Ad Quality and a notice to publishers, while AppLovin's proposed order would require the Ad Quality SDK itself to be modified within 30 days. Either route ends with changes to code that publishers have already shipped. Whatever the outcome, the case documents in unusual detail what a tracking SDK embedded by one network can observe about another network's impressions inside the same app: creative files, click destinations, per-impression revenue, waterfall latencies and screen touches.

Advertisers have a stake too. AppLovin argues that its clients' creatives, click-through destinations and campaign performance were exposed to a competing network without consent. Buyers reach this supply through more than one route; Display & Video 360, for example, has offered app mediation partners including AppLovin MAX and Unity LevelPlay as a distinct inventory source since 2024, and stopped bidding on multiple waterfall calls for mobile app inventory in October 2024. The mediation waterfall, which AppLovin says Ad Quality captured with latencies attached, is part of the auction record that bidders, by AppLovin's account, do not receive.

And the dispute is not confined to MAX. AppLovin's claims extend to impressions it wins in AdMob auctions, where Google added Unity and ironSource as bidding partners in July 2025. AppLovin describes MAX as a neutral, highest-bid-wins auction; Unity describes it as a dominant platform using that position against a rival. The court is now being asked to decide, at least provisionally, whether neutrality ends at the auction or extends to everything a bidder's code can read once its SDK is installed in the same app.

Timeline

Summary

Who: AppLovin Corporation, operator of the MAX mediation platform and the Axon-powered AppLovin Ads network, against Unity Technologies SF, operator of the LevelPlay mediation platform, the Unity Ads network and the Ad Quality SDK. AppLovin is represented by Quinn Emanuel Urquhart & Sullivan; Unity by Cravath, Swaine & Moore. The application is before Judge Joseph M. Quinn.

What: An ex parte application for a temporary restraining order and an order to show cause regarding a preliminary injunction, seeking to bar Unity from collecting or using AppLovin's Protected Data through Ad Quality, to disable that collection within five business days and to modify the SDK within 30 days. It accompanies a JAMS arbitration demand alleging breach of contract, trade secret misappropriation, interference with contractual and economic relations, and unfair competition. Unity denies wrongdoing, says the data comes from publishers with their permission, and had offered to switch Ad Quality off for MAX-mediated auctions on condition that AppLovin treat the dispute as resolved.

When: The arbitration demand was filed on September 27, 2026, the court petition on September 28 and the application on September 29. The filings schedule the hearing for September 30, 2026, at 11 a.m. Pacific, while Digiday reported September 29. A hearing on sealing is set for October 23, 2026. AppLovin says the contested collection has run since at least May 2025.

Where: The Superior Court of California, County of San Francisco, Department 302, case CPF-26-520212, alongside a JAMS arbitration seated in San Francisco County. The conduct at issue takes place inside mobile apps running AppLovin's MAX SDK and Unity's SDKs, and, according to AppLovin, in LevelPlay and AdMob auctions as well.

Why: AppLovin argues that per-impression revenue, auction mechanics and user-level engagement data from impressions it wins are confidential and could train a competitor's bidding models. Unity argues that the data belongs to publishers who authorize its collection and that AppLovin is using the dominance of MAX to shut down a rival ad-quality product. The outcome bears on what data a bidder's SDK may read about rival networks' ads inside the same app, and on how publishers reconcile contracts that describe that data in opposite ways.