E-commerce packaging is quietly going through a revolution — and envelopes are winning. Mailers, once seen as the humble alternative to cardboard boxes, are now the format of choice for millions of online shipments. Sustainability pressures and cost savings are pushing retailers to ditch heavy boxes in favour of lightweight, flexible mailers. As analyst Ryan Fox of Bloomberg Intelligence puts it, the shift is accelerating fast enough to chip away at corrugated boxes' dominance in 2026.
While the box-to-mailer transition had been progressing steadily for years, the pandemic put it into fever-pitch territory thanks to the e-commerce sales boom at that time. Suddenly, companies needed smarter, cheaper, greener solutions — and mailers delivered. Consulting founder Myles Cohen captures the scale perfectly: 'Think about the hundreds and hundreds of millions of products we're shipping every day. They're moving to envelopes.'
Mailers are available in multiple substrates, with poly and plastic bubble-lined versions prevalent for years. But the real innovation buzz now surrounds fiber-based alternatives. Brands are increasingly demanding paper mailers to meet their sustainability commitments, and manufacturers are racing to keep up. Features like gussets — which expand the envelope's capacity — and rightsizing technology are making fiber mailers viable for a much wider range of products.
Amazon has been a major catalyst here, doubling down on phasing out plastic and converting entire fulfillment centres to handle only fiber-based packaging. Where Amazon leads, the rest of the industry tends to follow — and that momentum is reshaping how we think about the humble envelope.
