The official campaign period for Brazil’s 2026 elections opened on Sunday with the two leading candidates returning to their political origins. Former president Luiz Inácio Lula da Silva (Lula) launched his bid at the Vila Euclides stadium in São Bernardo do Campo, the historic site of the ABC union strikes, under the slogan of a return to where it all began. Flávio Bolsonaro, son of former president Jair Bolsonaro and the Liberal Party (PL) nominee, held his rally in Copacabana wearing a green‑yellow jersey emblazoned with the words “my party is Brazil”.
The monitoring firm Palver tracked the reaction in public WhatsApp groups, on X and on Instagram from Saturday through Sunday night. In terms of raw mention volume, Lula dominated: he accounted for 63 % of all references to presidential contenders in WhatsApp groups, 57 % on Instagram and 41 % on X. Flávio Bolsonaro hovered between 28 % and 30 % across the three platforms.
When users discussed which candidate had the “best first day” without passing judgment on the individuals, Lula again led: 67 % of WhatsApp comments, 64 % of Instagram comments and 47 % of X comments named him, versus slices ranging from 31 % to 40 % for the senator. The image of a packed Vila Euclides and accompanying promotional videos gave the Workers’ Party candidate a narrative of a strong start.
Sentiment, however, painted a more fragmented picture. In messages that explicitly praised or attacked a candidate, Instagram showed a uniformly positive tilt—70 % to 78 % favorable mentions for all contenders—reflecting the platform’s overall bias rather than candidate differences. On X, enthusiasm was highest for Renan Santos (62 % supportive messages) followed closely by Flávio Bolsonaro (61 %); Lula’s sentiment split evenly, with 47 % positive and 53 % negative. Ronaldo Caiado attracted the most hostility on X, appearing in 83 % of negative mentions. Gilberto Kassab’s declaration that the “centrão” is aligned with Lula was seized upon by both sides, fueling posts such as “Kassab is Lula, Caiado is Lula, Zema is Lula, Renan is Lula”.
Public WhatsApp groups displayed a less performative, more dialogic tone. No candidate finished the opening day with more support than opposition. Flávio Bolsonaro faced the least rejection: 51 % negative mentions versus 49 % positive. Lula accumulated 60 % negative mentions, driven by backlash to his Vila Euclides mobilization, where critics answered with chants of “fora Lula” and “Lula pior que a pandemia”.
Analysts separated organic debate from mass‑diffusion behavior. Roughly 79 % of messages about candidates in WhatsApp groups exhibited a coordinated, automated pattern lacking spontaneous exchange. Among the remaining organic contributors, 64 % of messages mentioning Lula were attacks, while 57 % of those citing Flávio Bolsonaro were also negative. In the coordinated‑diffusion subset, attacks on Lula fell to 58 % and the conversation around Flávio balanced at roughly equal parts support and opposition.
Temporal patterns showed the morning belonged to Lula, who at times captured up to 82 % of the WhatsApp conversation as activists streamed to the ABC stadium. The afternoon saw Flávio Bolsonaro’s share climb above 40 % as images from Copacabana circulated. The third‑place contender, Renan Santos, barely registered on WhatsApp; his presence was concentrated on X, where he garnered 9 % of total volume and the highest proportion of supportive messages among the candidates fielded.