The short answer is yes, but with a caveat. Urban planter boxes with a built-in compost tea spigot are not yet a mainstream, standardized product. You can find raised beds and sub-irrigated planters with drainage or reservoir spigots, and a growing number of niche garden systems combine composting, worm farming, and liquid fertilizer collection. However, a planter explicitly marketed with a compost tea spigot is still a specialty item, often sold by small fabricators, permaculture suppliers, or made to order.
What the feature actually means is important. A compost tea spigot is usually a tap at the lowest point of a separate compost or tea reservoir. Compost and water sit in a screened chamber; microbes and nutrients leach into the liquid; the spigot lets you drain diluted compost tea for plants. It should not be confused with a standard drainage spigot on a self-watering planter, though some DIYers retrofit those for a similar purpose.
For urban gardeners, the concept is appealing because it saves space. A planter box can grow herbs or vegetables while producing a mild liquid feed. Good designs separate the compost chamber from the root zone, include mesh or a filter to prevent clogging, use a spigot with a removable screen, provide a lid to control odors and rain, and place the tap high enough to avoid sludge. A vent and overflow are also useful. If the spigot sits flush with the bottom, it may clog; a slight recess or sludge trap is better.
When shopping, search terms like compost tea planter, worm farm planter with tap, sub-irrigated planter with reservoir spigot, and compost tea spigot raised bed can help. Ask whether the spigot draws from a dedicated tea chamber or just drainage. Check capacity, food-safe materials, UV resistance, winter performance, and whether the compost chamber is accessible. For balconies, choose a compact model with a lockable tap and overflow protection. For rooftops, consider weight when the reservoir is full.
If you cannot find an off-the-shelf model that fits, a custom build is straightforward for a handy DIYer: use a sturdy planter box, add a sealed lower reservoir, fit a bulkhead spigot with a screen, and create a removable compost basket above it. Keep the compost mature and avoid adding meat, dairy, or pet waste. Dilute the tea before use and apply it fresh; do not store it for long periods. In short, yes, urban planter boxes with built-in compost tea spigots exist in niche and custom forms, but you may need to shop carefully or build one to get exactly what you want.