Choosing an SEO API: Five Things That Actually Matter
SEO API buying decisions come down to five questions — coverage fit, pricing shape, agent access, freshness, and what the free tier really gives you. A checklist from the inside.
If you're shopping for an SEO API, the feature matrices all look the same — volumes, SERPs, difficulty, backlinks, rank tracking. The differences that actually bite show up in five places, and none of them are on the comparison sites. This is the checklist we'd hand a friend, written from the inside of running one.
1. Coverage should match your workflow, not the brochure
The question isn't "does it have data" but "does it have your decision's data". A portfolio player hunting new niches needs first-seen dates and rising-term detection; an agency defending ten clients needs rank tracking and backlink indexes; a programmatic builder needs bulk volumes and SERP shapes at scale. Buy the coverage your weekly decision actually consumes — you'll pay for the rest either way.
2. Pricing shape matters more than pricing level
Per-seat subscriptions assume a human clicking. If your workload is scripts and agents, a seat is dead weight: you want pay-per-query with a balance, so quiet weeks cost nothing and batch days don't need a plan upgrade. If you run 5 sites, do the math on 12 months of your realistic call volume before signing anything annual — the "cheaper" plan is often the expensive one at your scale.
3. Can your AI agent call it natively?
This one is new and it's decisive. Half of keyword workflows are now "ask the agent". An API your agent can't call directly means glue code, and glue code is where quotas, auth and errors go to hide. Native MCP support — the protocol Claude, Cursor and friends already speak — turns the data source into a tool your agent can discover and call. REST for your code, MCP for your agents, same key.
4. Freshness has a cadence — read it
"Monthly database" is a legitimate product, but it cannot see a term born last Tuesday. If your edge is timing, you need surfaces that update daily — and you need the vendor to say so plainly, including what's cached and how stale a snapshot can be. Freshness claims without timestamps are marketing.
5. Judge the free tier by what it locks
A free tier that's a crippled trial teaches you nothing. The useful kind lets you run a real workflow end-to-end: query the actual data, hit the actual limits, see the actual response shapes. Whatever the card on the pricing page says, test the free path before you pay — it predicts the paid experience better than any demo.
Where wordradar fits — and doesn't
wordradar is built for the timing edge: a suggest ledger with first-seen dates (20,734 words this week, 693 added in a day), Trends rising confirmation, HN new-site radar, structural SERP difficulty, and a Stripe referral leaderboard — over REST and native MCP, free Top-20 boards, pay-per-query credits, no subscription. If you need a full backlink index or rank tracking for 50 clients, that's not us — we'd rather be honest about the edge we do cover.