Your competitors rent every click. Own yours before the Series B.

Honest answer: later than founders fear and earlier than they act. Pre-product-market-fit, heavy SEO spend is usually wrong (the compounding asset compounds toward a positioning you may pivot away from), but the cheap foundations, clean technical base, entity setup, a domain accumulating age and a few cornerstone pages, cost little and pay whenever growth starts. Post-PMF with 12+ months runway, SEO becomes one of the best CAC-reducers available, precisely because competitors on paid channels are renting what you can own.

CAC arithmetic: venture-funded categories bid paid channels to painful levels, and every funded competitor rents the same clicks forever. Organic positions, once earned, decouple acquisition from spend, which changes unit economics in exactly the way later-stage diligence rewards. Add the AI layer: buyers researching tools ask ChatGPT and Perplexity, and cited startups enter consideration sets no ad budget reaches.

Pre-seed/seed: foundations only, technical cleanliness, entity and schema setup, cornerstone pages for the category and problem, founder-led content where it is cheap and authentic. Series A and beyond: the compounding engine, programmatic where data justifies it, comparison and alternative pages (the highest-intent startup SEO there is), integration pages for every ecosystem you touch, and digital PR that doubles as fundraise-visibility. We scope by stage and say plainly when a startup should spend on ads instead this quarter.

"[Competitor] alternatives" and "[You] vs [Competitor]" queries are bottom-funnel buyers actively choosing, and startups that build honest comparison pages early own decision moments incumbents ignore. Honest is the operative word: pages that concede real trade-offs convert better and survive scrutiny (and the incumbents' legal teams). This is usually the fastest revenue-relevant SEO a B2B startup can ship.

It is the most under-priced asset most startups hold: founders carry authentic expertise and a story trade press will actually cover, and E-E-A-T systems reward named, verifiable authors. The play: founder bylines on cornerstone content, opinionated takes on category direction, and build-in-public material repurposed into linkable assets. We ghost-structure it (founders talk, we architect and edit) so it ships without eating founder weeks.

By building the durable layer separate from the bet layer: domain equity, technical base and founder authority survive any pivot; category-specific content is the bet layer, sized to conviction. Startups that understand this split spend correctly at every stage, and the ones that skipped foundations pay a cold-start tax exactly when growth was supposed to accelerate.

Foundation packages (technical + entity + cornerstone architecture) from £1,200 one-off, deliberately affordable at pre-seed. Growth retainers from £1,200/month post-PMF, scaling with ambition: comparison/integration programmes and digital PR typically £2,000-£3,500/month. Equity conversations: no, politely, cash keeps advice honest.