Configuration

The whole template styling is driven by TbConfiguration. Create an instance, tweak what you need and pass it to the builder — everything not touched keeps its sensible default:

TbConfiguration config = TbConfiguration.newInstance();
config.getContent().setWidth(800);        // inner content width (default 570)
config.getContent().setFull(true);        // stretch content-box to full width
config.getContent().setBackground("#F8F9FC");
config.getBody().setBackground("#EDEFF3");

HtmlTextEmail email = EmailTemplateBuilder.builder()
        .configuration(config)
        // … content lines
        .build();

Sections

TbConfiguration groups the settings by template area — each with colors, paddings, borders and fonts where applicable:

Section	What it styles
font	font families used throughout the template
text / imageText	paragraph styling (size, color, line-height)
button	border, border-radius, box-shadow of buttons
attribute	key/value block background and spacing
box	the content box (invoice-style boxed sections)
table	table borders and cell styling
body	outer body background + dark-mode colors
header	header padding, alignment, text styling
content	content width, background, padding, full, align
footer	footer text styling

Custom background colors work through the whole email — content.background is not hardcoded to white.

Frameless preset

TbConfiguration.newInstanceFrameless() removes the visual box-frame around the content: the body background matches the content, padding is reduced and header + content are aligned left — the result looks like a personally written email instead of a boxed transactional one. Great for invitations or signature-style emails:

TbConfiguration config = TbConfiguration.newInstanceFrameless();

HtmlTextEmail email = EmailTemplateBuilder.builder()
        .configuration(config)
        .preheader("You are invited to our summer party 🎉")
        .text("Hi Marie,").and()
        .text("we'd love to see you at our summer party next Friday at 6pm.").and()
        .button("Save my spot", "https://example.com/rsvp").blue().left().and()
        .copyright("rocketbase").url("https://www.rocketbase.io").and()
        .build();

Every setting can still be changed afterwards — for example content.align back to "center".

Dark mode

Dark-mode support is enabled by default (darkModeEnabled). Email clients that support it get adjusted colors automatically via prefers-color-scheme — the same email, no extra work:

You can provide dark variants for logos and images, or opt out entirely:

config.setDarkModeEnabled(false); // opt out entirely

.header().logo("https://…/logo.png").logoDark("https://…/logo-white.png").and()
.image("https://…/photo.jpg").srcDark("https://…/photo-dark.jpg").and()

Responsive behaviour

The generated HTML collapses to full width below a 600px viewport — no extra configuration needed.

Outlook specials

Outlook is the usual troublemaker — a few switches exist specifically for it:

• .space() lines render as fixed-height table rows that Outlook respects (regular margins are often stripped)
• buttons use border-based rendering so padding and margins survive
• extra style settings on TbButtonConfig / TbBoxConfig allow fine-tuning where Outlook deviates

Custom renderer

Since 2.6.0 you can hook into the rendering to modify the output — see EmailTemplateBuilder.builder() and the template sources if you need to go beyond the provided configuration.