The WhatsApp machine

1. 1

   8 seconds of TV. With a small party and no debates after the stabbing, Bolsonaro won the 2018 runoff with 55.1% of valid votes.

2. 2

   A pyramid of WhatsApp groups: few producers, many volunteer admins and millions of ordinary people. On top of that came mass messaging paid for by companies, according to Folha.

3. 3

   Distribution by ordinary people made up for missing TV time. Bought lists, hidden money and lies brought lawsuits and harm no democratic campaign should repeat.

Copy summary

If you're new to this, start with the fundamentals, from the vote goal to what the research says. Read the fundamentals

The operators rarely spoke in detail about the method; what is known comes mostly from reporting, from researchers who monitored public groups, and from the courts.

• Carlos Bolsonaro

  Rio de Janeiro city councillor, in charge of his father's social media

  According to Jair Bolsonaro himself and the press, he ran his father's digital marketing from 2010 and led the 2018 campaign's social media; in 2026 he was elected senator for Santa Catarina.

  Sources

• AM4 Brasil Inteligência Digital (Marcos Aurélio Carvalho)

  The 2018 campaign’s largest declared vendor

  Per Folhapress, it was paid about R$650,000; Carvalho said the firm ran broadcast lists, state groups and groups for reporting fake news, and directed the campaign films in the runoff. At Congress’s fake-news inquiry (CPMI, 2020) he admitted hiring Yacows for a single send to about 8,000 donors announcing a new phone number; he denied mass messaging, and nothing beyond that was proven against the campaign.

  Sources

• Volunteer group admins

  Operators of the network of groups and broadcast lists

  Supporters such as José Raimundo, who ran a group of São Paulo voters, and Carlos Nacli, linked to the Nas Ruas movement, who coordinated broadcast lists, described to the press how the network worked.

  Sources

• Patrícia Campos Mello

  Folha de S.Paulo reporter, author of A Máquina do Ódio (The Hate Machine)

  On October 18, 2018, she revealed that companies were buying mass-messaging packages targeting the PT (Workers' Party); her 2020 book recounts the investigation and the harassment she faced.

  Sources

• Fabrício Benevenuto (UFMG)

  Computer scientist, creator of the WhatsApp Monitor

  Built the system that tracked hundreds of public political groups and let journalists and fact-checkers see what was circulating.

  Sources

• Cristina Tardáguila (Agência Lupa) and Pablo Ortellado (USP)

  Fact-checker and researcher

  With UFMG, they checked the 50 most-shared images in 347 groups and, in The New York Times, asked WhatsApp to restrict forwarding.

  Sources

• David Nemer

  Media researcher (University of Virginia)

  Followed pro-Bolsonaro groups from March 2018 and described their pyramid structure and three user profiles.

  Sources

• Superior Electoral Court (TSE)

  Brazil's electoral judiciary; rapporteur Luis Felipe Salomão

  On October 28, 2021, it voted 7–0 against annulling the ticket's mandate, but acknowledged the mass messaging and disinformation and set a legal standard for future elections.

  Sources

• WhatsApp

  Platform; Ben Supple, public policy and elections lead

  Admitted in 2019 that bulk-messaging companies had violated its terms in the Brazilian election, and limited forwarding to five chats.

  Sources

Explanations from operators and from those who investigated the case, paraphrased. No message attacking any group is reproduced here.

• His son Carlos had handled his marketing and campaigning since 2010 and was the one who started the campaign on social media.

  Jair Bolsonaro, Interview with Jovem Pan, cited on Wikipedia (Carlos Bolsonaro article)

• Around 2010, searching his father's name on Google, he found only negative results; so he started a blog with family photos to build a positive image.

  Carlos Bolsonaro, Account cited on Wikipedia (Carlos Bolsonaro article)

• “We directly reached 10,000 people from all over Brazil.”

  Carlos Nacli, broadcast-list coordinator, Interview with El País, cited by Folha (DN, Oct 20, 2018)

• He was invited to run the group, removed anyone who stirred up trouble and said he kept fake news in check, though he claimed never to have seen any.

  José Raimundo, admin of a São Paulo group, Folha de S.Paulo, republished by DN, Oct 20, 2018

Bolsonaro entered 2018 with little TV time, little declared money and years of social media presence. Much of the campaign happened inside closed groups, out of sight of the press and the courts. That has made it hard, to this day, to measure what worked and who paid for what.

8 s

of free TV and radio airtime in the first round

R$2.5M

in declared campaign spending, against Haddad's R$37.5M

4 of 50

of the most-shared images in 347 groups were entirely true

55.1%

of valid votes in the runoff, October 28, 2018

From 2018 to the court ruling

1. Mar 2018Researcher David Nemer begins following pro-Bolsonaro WhatsApp groups.
2. Jul 2018WhatsApp begins testing limits: forwarding to up to 20 chats worldwide and five in India.
3. Sep 6, 2018Bolsonaro is stabbed in Juiz de Fora. He does not return to debates and focuses the campaign on social media.
4. Oct 7, 2018First round: about 46% of valid votes.
5. Oct 17, 2018Lupa, USP and UFMG show that only 4 of the 50 most-shared images in groups were true, and ask WhatsApp for temporary limits.
6. Oct 18, 2018Folha reveals that companies were buying mass-messaging packages against the PT, with contracts of up to R$12 million each.
7. Oct 28, 2018Runoff: Bolsonaro wins with 55.1%.
8. Jan 2019WhatsApp limits forwarding to five chats worldwide.
9. Oct–Dec 2019WhatsApp admits bulk-messaging companies violated its terms during the election; the TSE bans mass messaging in Resolution 23.610/2019.
10. Oct 28, 2021The TSE votes 7–0 against annulling the ticket's mandate, acknowledges mass messaging and disinformation with no proven link to the campaign, and adopts a legal standard for the future.

Three layers

Research and reporting describe three layers pushing the same content. Only the first was openly run by the campaign.

• Family commandThe accounts of the candidate and his sons, run by Carlos Bolsonaro from home, with videos and livestreams from the candidate.
• Volunteer pyramid networkA few influencers producing, devoted supporters running groups by state and city, and millions of ordinary people receiving and forwarding.
• Paid, opaque mass messagingAgencies that, according to Folha, sold mass sends to businesspeople. The TSE acknowledged the messaging but found no proof that the ticket had hired them.

The network fit a very specific environment: a messaging app that worked like a newspaper, rules that did not yet address mass messaging, and a campaign with neither TV time nor money.

Platforms

WhatsApp groups

Groups of up to 256 people by state, city or topic, run by volunteers. End-to-end encrypted: only public groups could be monitored by researchers and journalists.

Broadcast lists

Only the admin posts, and each list reached up to 256 contacts, who could forward on. This was the channel for seeding videos and images into the network.

Mass-messaging agencies

According to Folha (18 Oct 2018), agencies such as Quickmobile, Yacows, Croc Services and SMS Market sold sends of hundreds of millions of messages, at R$0.08–0.40 each, using their own databases segmented by region and income; the report named the retailer Havan among the buyers. Havan’s owner, Luciano Hang, denied it, and in 2020 a first-instance judge ordered Folha and the reporter to pay him damages; the paper appealed. WhatsApp later said bulk-messaging firms violated its terms; the TSE found no proof that people linked to the campaign bought the sends.

YouTube and Facebook

Where influencers produced and posted videos, and where groups coordinated actions such as mass subscriptions to the PSL party's channel.

TV and radio

Bolsonaro had 8 seconds of free election airtime; Geraldo Alckmin had 5 minutes and 32 seconds, and finished with under 5% of the vote.

Local conditions

• About 6 in 10 Bolsonaro voters read news shared on WhatsApp, against 38% of Fernando Haddad's voters (Datafolha, October 2018).
• 47% of WhatsApp users said they trusted what they received through the app (Datafolha).
• In 2018 a message could be forwarded to up to 20 chats at once; the five-chat limit only went worldwide in January 2019.
• Corporate donations to campaigns were banned; Folha described businesspeople's purchase of mass messaging as an undeclared donation.
• After the stabbing on September 6, Bolsonaro attended no debates and spoke mainly through his own channels.
• A small party (PSL) and a declared campaign budget of about R$2.5 million, against Haddad's R$37.5 million.

This describes what was documented; it is not a recipe. The legitimate part (your own presence, volunteers, native formats) is mixed with illegal and harmful practices; the lessons section separates the two.

Three supports

An owned presence, built early

Almost eight years of blog posts, profiles and videos before 2018. When TV time was lacking, the audience was already there.

Distribution by ordinary people

Content arrived through relatives, colleagues and neighbors, in family and neighborhood groups, where trust runs higher than in the press.

Emotion and identity

Voice notes from “people like us”, memes and short videos, designed to travel without context, which also made lying easier.

How a piece of content traveled

Based on Nemer's research, UFMG's monitoring and the 2018 reporting, a piece of content went through roughly these steps.

1. Produce Small groups of influencers created videos, images and voice notes, often with no source and no author.
2. Seed Broadcast lists and state-level “mother groups” pushed the piece into the network all at once.
3. Replicate Admins and devoted members forwarded it to dozens of groups; a single voter was sometimes in 40 groups.
4. Filter the bubble Anyone who disagreed was removed. Groups became homogeneous and rarely engaged with the other side.
5. Coordinate actions Groups organized tasks on other platforms, such as subscribing to YouTube channels and campaigns against artists' ads.
6. Jump outside The piece moved from political groups into family, work and church groups, where it gained the trust of whoever forwarded it.
7. Accelerate with money According to Folha, mass sends paid for by companies, using bought databases, multiplied the reach. This is the part the TSE found unlawful.

And again.

The 2018 network showed that real people, on the right channel and in the right format, are worth more than TV time. It also showed the cost of mixing that with hidden money, bought lists and lies.

What the law, the courts and the platforms said about what happened in 2018, and the rules that came afterwards.

Corporate donations are banned

Folha described businesspeople's purchase of mass messaging as an undeclared corporate donation, banned under Brazilian electoral law.

Opt-in lists only

The law only allows campaigns to use contacts obtained voluntarily. Buying third-party databases is illegal.

Mass messaging banned

TSE Resolution 23.610/2019 banned mass messaging without consent from the 2020 elections onwards.

The TSE standard (2021)

Mass sending of disinformation through apps can amount to abuse of economic power and misuse of the media and, depending on its seriousness, lead to annulment of a mandate. The court set out five criteria: content, reach, scale, the candidate's involvement and corporate funding.

WhatsApp's terms

Automated and bulk messaging violates the terms of service. In 2019 the company was banning more than 2 million accounts a month worldwide and began suing mass-messaging agencies.

Forwarding limit

Since January 2019, a message can only be forwarded to five chats at once.

Harassment has consequences

In 2022 the São Paulo Court of Justice upheld Bolsonaro's conviction for insulting Patrícia Campos Mello, with R$35,000 in damages.

Data protection

Since 2020 the LGPD (Brazil's data protection law) also applies to campaigns in Brazil. In the European Union, the GDPR treats political opinion as sensitive data, and Regulation (EU) 2024/900 allows targeting political ads only with explicit consent and without sensitive data and requires labels and transparency notices on paid ones. Since October 2025, Meta has not accepted political, electoral or social-issue ads in the EU, and Google has stopped serving political ads. See the “Law and platforms in the European Union” section in Fundamentals.

The effect can't be measured

With encrypted groups and many other factors (the stabbing, rejection of the PT, the economy), no study can say how many votes WhatsApp shifted.

The courts didn't close the loop

The TSE acknowledged mass messaging and disinformation but found no proof that people linked to the ticket had paid for it. Part of the evidence never reached the case.

It wasn't one-sided

Researchers found misleading content in both left-wing and right-wing groups, although most of the rumors checked hurt Haddad.

The platform changed the rules

A five-forward limit, bans on agencies and the TSE prohibition: what worked in 2018 was later shut down or criminalized.

What came next

Bolsonaro was declared ineligible by the TSE in June 2023 over events in 2022. On September 11, 2025, the STF sentenced him to 27 years and 3 months for a coup plot, and he was jailed in November 2025. In 2026, Carlos Bolsonaro was elected senator for Santa Catarina and Flávio Bolsonaro lost the runoff to Lula. None of these decisions ruled on the 2018 digital campaign.

Five questions on the mechanism, the red lines and the responses. Each answer comes with an explanation.

This case study draws on reporting from 2018 to 2026, research on public WhatsApp groups, TSE rulings and statements by the platform. Pages accessed on October 26, 2026.

Updated 26 October 2026