SEO Tools by Task: Free Options, Paid Stacks, Pricing, Limits, and Caveats

Overview

There is no single best SEO tool — the right choice depends on the job. Google Search Console is the strongest free option for measuring your own site, Ahrefs leads for competitor and backlink research, Screaming Frog for technical crawling, Surfer or Clearscope for content optimization, and Semrush for broader all-in-one management and rank tracking. Most readers need two or three of these, not all of them.

That task-first framing matters because editorial comparisons of SEO software consistently assign different products to different jobs rather than crowning one winner. Zapier’s roundup names Semrush for rank tracking, Ahrefs for competitor research, Screaming Frog for technical SEO, and Clearscope for content optimization, while Marketer Milk’s comparison maps Google Search Console to first-party data and indexing, Ahrefs to competitor and backlink research, Semrush to all-in-one management, and Surfer to content optimization. The overlap between independent reviewers is a useful signal; the disagreements are equally useful, and this guide flags both.

The matrix below summarizes the shortlist by task, including the main caveat you should weigh before committing to any of them.

Task	Named option	Best fit	Main caveat
Owned-site measurement and indexing	Google Search Console	Any site owner; free for verified properties	Covers only your own verified sites — no competitor view
Keyword, competitor, and backlink research	Ahrefs	Teams that need competitor intelligence	Paid plans use credit and project limits; data is modeled, not first-party
All-in-one management and rank tracking	Semrush	Generalists consolidating several jobs into one platform	Breadth can exceed what small sites need; verify current pricing
Technical audits and crawling	Screaming Frog SEO Spider	Technical practitioners auditing site structure	Free version capped at 500 URLs; output needs interpretation
Content optimization	Surfer or Clearscope	Content teams producing at volume	Guidance is directional, not a ranking guarantee
Local listing checks	Moz free SEO tools	Local businesses doing foundational checks	Not a substitute for multi-location tracking platforms
AI-search visibility	Ahrefs or Semrush AI features	Brands monitoring ChatGPT, AI Overviews, AI Mode	Feature availability does not prove data quality or coverage

The rest of this guide explains each recommendation, when a free tool is enough, what the verified pricing actually looks like once limits and add-ons are counted, and how to assemble a minimum viable stack for your role.

How to compare SEO tools before choosing

Before comparing products, you need to know which category each one belongs to, because the categories are not substitutes for each other. Zapier’s taxonomy distinguishes audit tools, which “perform analysis of one or more metrics related to search engine optimization efforts,” from all-in-one tools that “can make tools from the other categories redundant and tend to include advanced features like automation and AI.” A crawler, a rank tracker, a content editor, and a first-party measurement console do different work; ranking them against each other on a single scale produces misleading conclusions.

The evaluation criteria that recur across editorial comparisons are practical rather than technical. Zapier’s methodology weighs value (“how well does the price represent the quality of the product?”), user experience (whether “the learning curve should be low enough for users to reliably access any feature they need”), and integrations, on the reasoning that digital marketers “tend to use many different software products” and need SEO tools to connect with reporting, scheduling, and CRM platforms. Those three criteria — plus feature depth and explicit limits — are a sound baseline for your own shortlist.

The second distinction that matters is data provenance. Google Search Console reports what Google actually observed about your verified properties — first-party data, in Marketer Milk’s framing. Almost every other metric you will see in an SEO tool is a modeled estimate built from a vendor’s third-party database: rank positions sampled on a schedule, traffic estimated from clickstream and keyword models, backlinks discovered by the vendor’s own crawler. When a vendor’s traffic estimate disagrees with your analytics, or two tools report different rankings for the same keyword, that is not a malfunction; it is the expected behavior of independent models sampling a moving target. Treat first-party data as the reference for your own site, treat vendor estimates as directional intelligence about competitors, and avoid making decisions that depend on third-party numbers being precise.

Finally, be honest about the evidence behind any recommendation — including the ones in this article. The editorial sources this guide draws on vary in rigor and say so themselves. Zapier’s reviewer discloses: “I was able to dig into a number of tools myself, but I wasn’t able to personally test each of them,” filling gaps with user accounts, demos, and aggregated reviews. Morningscore’s comparison is more candid still: “I am not following any strategy or defined method… I could be wrong in my judgement.” This guide handles that uncertainty in three ways. Task-to-tool mappings are used only where multiple independent sources agree. Exact prices and limits are taken from official provider pricing pages where available — currently Ahrefs, Screaming Frog, and Surfer — and flagged as unverified elsewhere. And where sources conflict, as they do on some prices and on rank-data quality, the conflict is stated rather than smoothed over. Prices and plan structures change frequently, so verify the official page before purchasing regardless of what any comparison article reports.

Best SEO tools by task

The most reliable way to choose SEO software is to start from the job, not the brand. The sections below cover the seven jobs that recur across the strongest comparisons: owned-site measurement, research, rank tracking and reporting, technical auditing, content optimization, local checks, and AI-search visibility. For each, you will find the named option with the strongest editorial support, why it fits, how access works, and — just as important — the material limitation that determines whether you actually need it. No product below is universally best; several are genuinely best at one thing and mediocre or irrelevant for others. If you read only one section, read the one matching the task you cannot currently do.

Owned-site measurement and indexing

If you own or manage a website, Google Search Console is the first tool to set up, and it costs nothing. Marketer Milk names it best for “first-party data + indexing,” and that framing is exact: it reports what Google itself observed about your verified properties — the queries that surfaced your pages, how they were indexed, and how they performed in Google’s results. No third-party tool can replicate that, because no third party has Google’s internal view of your site.

The workflow is straightforward: verify ownership of your property, then use the console as your reference point for search performance and indexing status. When a paid tool’s estimates disagree with Search Console for your own site, the first-party data wins.

The limitation is structural, not a quality problem. Search Console only reports on properties you have verified, which means it can tell you nothing about competitors — you cannot verify someone else’s site. It also reflects one search ecosystem. The moment your questions shift from “how is my site doing?” to “what are competitors ranking for, and who links to them?”, you have left the territory a first-party console can cover, and that is precisely the gap third-party research databases exist to fill. Set up Search Console regardless of what else you buy; just do not expect it to substitute for competitive research, and do not let a vendor’s estimates about your own site override it.

Keyword, competitor, and backlink research

For research beyond your own properties, the two names that recur across independent comparisons are Ahrefs and Semrush. Zapier picks Ahrefs for competitor research; Marketer Milk picks it for “competitor & backlink research” and names Semrush for all-in-one SEO management, adding that its favorite tools for “keyword research and analyzing competitors” are Ahrefs, Semrush, and Google Autocomplete. If your central question is what competitors rank for, where their links come from, and which keywords are worth pursuing, Ahrefs has the strongest editorial support in this corpus; Semrush is the closer choice if research is one job among several you want on a single platform.

Two caveats should shape the purchase decision. First, everything these tools tell you about other sites comes from the vendor’s modeled database — crawled links, sampled rankings, estimated traffic. It is genuinely useful competitive intelligence, but it is an estimate, and it will not always match what a site’s owner sees in their own first-party data. Second, cost is metered, not flat. Ahrefs’ official pricing page lists the Lite plan at $129 per month with 5 projects, 750 tracked keywords, 1,000 credits per user, and one included user; additional users cost $40 per month each on Lite, and and, once additional pay-as-you-go credits or data have been enabled, charges apply automatically when consumption exceeds plan limits. Note that Marketer Milk quotes Ahrefs Lite at $108 per month with 500 credits — a conflict with the official page that illustrates why corpus prices should be treated as provisional. Buy a research tool when competitor questions are blocking real decisions, and budget for the limits, not just the sticker price.

Rank tracking and stakeholder reporting

Ongoing position monitoring and stakeholder reporting is where Semrush has the clearest editorial support. Zapier names it the pick for SEO rank tracking, and Semrush’s own product page advertises position tracking across “Google, Bing, Baidu, ChatGPT, and AI Mode,” with traditional SEO and AI search results reportable in one platform. Marketer Milk frames the same platform as the one tool “that can pretty much do everything you need from an SEO platform,” and notes that its multi-site tracking and reporting is “specifically designed for SEO agencies, freelancers managing multiple clients, and marketing teams that need to track and report on several websites at once.” If your job includes recurring reports to clients or executives, consolidated tracking-plus-reporting is the feature that justifies the platform.

Two honest qualifications apply. First, tracked rankings from any third-party tool are sampled observations of results that vary by location, personalization, and time of day — different tools will report slightly different positions for the same keyword, and the editorial sources in this corpus assess rank-data quality with varying rigor and openly subjective methods. Use tracked positions for trends and reporting, not as ground truth to the decimal. Second, exact Semrush pricing could not be verified against an official pricing page for this article: current Semrush pricing was not officially verified for this article, while Marketer Milk cites an Essential plan at $65 per month with 5 projects and 500 daily tracked keywords — figures that appear to describe different plan structures. Confirm the current plan lineup on Semrush’s site before budgeting.

Technical SEO audits and crawling

For crawling a site and diagnosing technical issues, Screaming Frog SEO Spider is the consensus pick — Zapier names it for technical SEO and Marketer Milk for technical SEO audits. It is desktop crawler software rather than a cloud dashboard, and its access model is unusually generous for evaluation: the official pricing page confirms the free version crawls up to 500 URLs and includes broken-link detection, page title and meta data analysis, hreflang auditing, duplicate-page discovery, and XML sitemap generation. The paid licence — $279 per year per user, with volume discounts down to $235 per licence at 20 or more — removes the URL cap and unlocks features such as scheduling, JavaScript rendering, saved crawls, and crawl comparison. Zapier quotes the paid version at $259 per year, which conflicts with the official page; treat the official figure as current and reverify before purchase. Note that licences are per user: two people crawling need two licences.

For lighter-weight, report-style audits rather than raw crawling, Zapier’s comparison also names SEOptimer as its audit pick — a reasonable option when you need a readable summary rather than a full crawl dataset.

The caveat that matters most is interpretive, not technical. A crawler surfaces everything it finds — including issues that are harmless in context, deliberate configuration choices, or low-priority noise. Crawl output is an input to diagnosis by someone who understands the site, not a to-do list to implement mechanically. Buy Screaming Frog when your site exceeds 500 URLs or you need scheduled and comparative crawls; skip the licence if the free tier covers your site and your questions.

Content optimization

Content optimization tools analyze how well a draft covers a topic relative to what currently ranks and guide writers toward closing gaps. The two specialist names with editorial support here are Surfer — Marketer Milk’s pick for content optimization — and Clearscope, Zapier’s pick for SEO content optimization. Marketer Milk’s recommended progression is telling: start with free Google tools, then, “when it comes to the content creation part,” move to Surfer, Claude, or Clearscope. These are writing-workflow tools, and their value scales with content volume: a team publishing regularly gets structured, repeatable guidance that would otherwise require manual SERP analysis for every article, while a site publishing occasionally may not produce enough content to justify the subscription.

On access, Surfer’s pricing is officially verifiable: its pricing page lists a Discovery plan at $49 per month for testing, Standard at $99, Pro at $182, Peace of Mind at $299 with API access, and Enterprise at $999, with annual plans charged upfront for the entire year at a discount of up to 17% versus monthly payments. Clearscope’s current pricing was not verified for this article; check its official page directly.

The essential caveat: optimization scores measure alignment with a model of ranking content, not future rankings. A high score does not guarantee traffic, and chasing a score can degrade writing quality. Use these tools to inform coverage and structure, keep editorial judgment in charge, and buy one only when content production is a core, recurring workflow.

Local SEO and listing checks

Local search is a narrower job than general SEO, and the supported starting point in this corpus is modest: Moz’s free SEO tools collection includes free tools for local listing audits alongside link analysis, keyword research, and webpage performance checks. For a local business that mainly needs to verify its listings are accurate and consistent, that free foundation — combined with Google Search Console for the website itself — covers the basics without a subscription.

Be clear about what a listing audit is not. Checking listing accuracy is a point-in-time diagnostic; it is not interchangeable with a full local platform that tracks rankings across many locations, manages reviews, or produces recurring multi-location reports. Businesses with several locations, or agencies serving local clients, will likely outgrow free checks and need paid tracking and reporting — but the evidence reviewed for this article does not support ranking specific paid local platforms against each other, so that comparison is deliberately left out rather than guessed at. Start with the free listing audit, confirm whether your actual gap is diagnostics or ongoing management, and evaluate paid local software against that specific gap using current official documentation.

AI-search visibility and prompt tracking

Tracking how your brand appears in AI-powered search experiences is now an advertised capability of mainstream SEO vendors, and two are directly supported by the evidence. Ahrefs’ free tools include an AI Visibility Checker that shows “how often your brand is mentioned across AI platforms like ChatGPT, Gemini, Perplexity, and more,” plus an AI Overviews Tracker for monitoring “visibility, citations, and answer volatility in Google AI Overviews.” On the paid side, Ahrefs’ official plans include tracked prompts as a metered limit — 5 on Lite, 10 on Standard, 20 on Advanced, per its pricing page. Semrush advertises position tracking that spans “Google, Bing, Baidu, ChatGPT, and AI Mode,” reporting traditional and AI search results in one platform, and verify current access to and pricing of any AI-visibility add-ons directly on Semrush’s official site, since those details were not verified for this article.

The critical distinction here is between feature availability and demonstrated quality. Vendors can truthfully advertise that they track AI platforms; that tells you nothing, by itself, about how relevant the tracked prompts are to your customers, how consistent coverage is across countries and languages, or how stable the measurements are. Hands-on editorial reviews in this space openly acknowledge subjective and fallible judgment, and answer volatility — which Ahrefs’ own tracker measures — is itself a signal that AI results move constantly. Treat AI-visibility tracking as an aid to analysis: use the free checkers first to see whether the output is meaningful for your brand and market, and only pay for prompt tracking or an add-on once it demonstrably informs decisions you would not make otherwise.

Build a free SEO foundation before paying

For most beginners and budget-constrained site owners, the correct first step is not choosing a paid platform — it is exhausting the free foundation. Marketer Milk’s recommendation is explicit: “For beginners, I generally recommend using the free SEO tools that Google gives you. This includes using Google Autocomplete, Google Keyword Planner, Google Search Console, and even Google Trends.” Together, those cover first-party performance measurement and indexing (Search Console), keyword discovery (Keyword Planner and Autocomplete), and demand trends over time (Trends) — a genuinely functional starting stack at zero cost.

Vendors extend that foundation with limited free utilities. Ahrefs publishes a collection of free tools that, in its own words, are “limited compared to a paid Ahrefs account” but “still immensely valuable for anyone who’s just starting out in SEO,” including the AI Visibility Checker and AI Overviews Tracker described above. Moz offers free tools for link building and analysis, keyword research, webpage performance, and local listing audits. And Screaming Frog’s free version is a real working crawler up to 500 URLs, including broken-link detection, metadata analysis, and sitemap generation per its official pricing page — enough to fully audit many small sites without spending anything.

Understand the boundaries of this free tier, because they define when paying becomes rational. Google’s tools observe your own verified properties and one search ecosystem; they cannot tell you what competitors rank for or who links to them. Vendor free tools are deliberately limited samples of the paid product. The free crawler stops at 500 URLs. None of this is a flaw — it simply means the free foundation answers “how is my site doing and what might I write about?” but not “how do I beat specific competitors at scale?”

Upgrade when a specific, recurring limitation blocks real work rather than on a general sense that professionals pay for software. Practical triggers include:

• Competitor questions you cannot answer: you repeatedly need competitor keyword or backlink data that no free tool provides — the trigger for Ahrefs or Semrush.
• Site size: your site exceeds Screaming Frog’s 500-URL free crawl limit and technical auditing matters — the trigger for the $279-per-year licence.
• Content volume: you publish enough that manual SERP analysis per article is a genuine time cost — the trigger for Surfer or Clearscope.
• Reporting obligations: you owe recurring reports on multiple sites to clients or stakeholders — the trigger for a consolidated platform.

Until one of those triggers fires, the free foundation plus disciplined use of it will outperform an underused subscription. When one does fire, buy the tool that resolves that trigger specifically — the next section explains how to decide between a broad platform and a specialist.

When an all-in-one suite or specialist tool is the better buy

The suite-versus-specialist decision reduces to one question: does the additional purchase close a material gap, or does it duplicate what you already have? Zapier’s framing sets the standard on both sides: “Tools with specific use cases should be effective enough to justify subscriptions for users with more comprehensive tools, just as comprehensive tools should have extensive feature suites, and paid tools in general should be more useful than free options.” In other words, a specialist must earn its place next to a suite, and a suite must earn its price against free tools.

All-in-one platforms make sense when consolidation is the value. Zapier’s category definition notes that all-in-one tools “can make tools from the other categories redundant,” and Marketer Milk describes Semrush as the one paid tool “that can pretty much do everything you need from an SEO platform.” If you currently pay for — or are about to pay for — separate keyword research, rank tracking, and reporting products, a single platform can replace several subscriptions, reduce data reconciliation between tools, and give stakeholders one reporting surface. This logic is strongest for generalists and agencies whose work spans many SEO jobs at moderate depth.

A suite becomes excessive when your actual workload uses a small fraction of it. A site owner who needs technical crawling and first-party measurement gains little from a platform whose main strengths are competitive research and multi-client reporting; Search Console plus a Screaming Frog licence covers that workload at $279 per year versus a recurring platform subscription. Paying for breadth you do not use is the most common form of tool-stack waste, and the fix is to inventory the jobs you perform monthly before comparing feature lists.

Specialists justify a separate subscription when their depth solves a problem the suite handles superficially or not at all. The corpus supports several such cases: Screaming Frog for deep technical crawling as desktop software with per-user licensing, Surfer and Clearscope for structured content-optimization workflows built into the writing process, and dedicated first-party measurement through Search Console, which no paid suite replaces. The test is concrete: name the workflow the suite cannot do, confirm the specialist actually does it, and price the specialist against the value of that specific gap — not against the suite as a whole.

Apply the redundancy test in the other direction too. Before renewing a specialist subscription alongside a suite, check whether the suite has since absorbed the capability well enough for your needs — vendors expand feature sets continuously, and AI-visibility tracking is a current example of a capability appearing in both suites and free vendor tools. A defensible stack has no two subscriptions doing the same job at the depth you actually require.

Pricing and limits: the verified subset and remaining gaps

Advertised entry prices understate real costs whenever plans meter usage, charge per user, or sell key features as add-ons. This section presents exact figures only for the three tools whose official pricing pages were verified for this article — Ahrefs, Screaming Frog, and Surfer — and explicitly flags what remains unverified. All figures are in USD as listed on the official pages cited; billing basis is labeled per row, and all of it should be reverified at purchase time because packaging changes frequently.

Tool and plan	Price and billing basis	Key limits and quotas	Add-ons and billing rules
Ahrefs Lite	$129/mo (official pricing)	5 projects, 750 tracked keywords, 5 tracked prompts, 100,000 crawl credits/mo, 1,000 credits per user/mo, 6 months historical data, 1 user	Up to 2 extra users at $40/mo each; automatic pay-as-you-go charges when usage exceeds limits, but only if pay-as-you-go credits or data have been enabled; PAYG credits expire after three billing months
Ahrefs Standard	$249/mo	20 projects, 2,000 tracked keywords, 10 tracked prompts, 500,000 crawl credits/mo, unlimited credits per user, 2 years historical data, 1 user	Up to 5 extra users at $60/mo each
Ahrefs Advanced	$449/mo	50 projects, 5,000 tracked keywords, 20 tracked prompts, 1.5M crawl credits/mo, 5 years historical data, 1 user	Up to 10 extra users at $80/mo each
Ahrefs Enterprise	$1,499/mo, annual commitment required	From 3 users,	Extra users $100/mo each
Screaming Frog free	Free (official pricing)	500-URL crawl limit	—
Screaming Frog paid	$279 per licence per year	Unlimited crawl (subject to machine memory/storage); licences are per user	Volume discounts: $265 (5–9 licences), $249 (10–19), $235 (20+)
Surfer Discovery	$49/mo (official pricing)	Positioned for testing Surfer and baseline optimization	Annual plans charged upfront for the full year, up to 17% discount vs monthly; cards for monthly/yearly, bank transfer yearly only
Surfer Standard / Pro / Peace of Mind	$99 / $182 / $299 per month	Peace of Mind includes API access and uncapped optimization	Enterprise tier at $999/mo for custom scale

Three billing rules in this table deserve emphasis because they change effective cost. Once a customer enables additional pay-as-you-go credits or data, Ahrefs charges automatically when consumption exceeds plan limits, and those purchased credits expire after three billing months — a heavy-usage month can cost meaningfully more than the plan price. Screaming Frog licences are strictly per user, so a four-person technical team pays $279 × 4 = $1,116 per year at the standard rate. Surfer’s annual plans are charged for the entire year upfront, which is a cash-flow consideration even with the discount.

Equally important is what this table does not cover. Semrush pricing could not be verified against an official pricing page for this article: official current pricing remains unverified, and official current AI-feature pricing and packaging likewise still require verification, while Marketer Milk cites an Essential plan at $65 per month — figures that likely reflect different plans or bundles and should not be treated as comparable tiers. Clearscope, Mangools, SEOptimer, and Moz’s paid products likewise lack verified current pricing here. Where corpus sources disagree with official pages — Zapier’s $259 Screaming Frog figure versus the official $279, Marketer Milk’s $108 Ahrefs Lite versus the official $129 — the official page governs, and the safest habit is to treat every third-party price quote, including this article’s, as a snapshot to reconfirm on the vendor’s site before signing.

Minimum viable SEO tool stacks by user type

The goal of a stack is full coverage of your actual jobs with zero redundant subscriptions. Marketer Milk’s practical sequence — free Google tools first, then content tools like Surfer or Clearscope, then research tools like Ahrefs or Semrush as competitive questions mature — generalizes well, and Zapier’s reminder that the right product “will depend on factors like your budget, your organization’s size, and the tool’s ability to integrate with other software you depend on” supplies the organizational lens. The recipes below apply both, adding one paid tool only when a named trigger justifies it.

Solo site owner or independent marketer. Foundation: Google Search Console, Keyword Planner, Autocomplete, and Trends, plus Screaming Frog’s free 500-URL crawler and vendor free utilities such as Ahrefs’ AI Visibility Checker. First paid upgrade: a research platform (Ahrefs from $129/month per its official pricing, or Semrush after verifying current plans) — but only when competitor questions are actively blocking decisions. Many solo sites run productively on the free foundation for a long time; Zapier also names Mangools as its beginner pick if a lighter paid entry point suits you better. Skip specialists until a specific workflow demands one.

Content team. Foundation: Search Console for measuring what published content actually earns, plus free keyword discovery tools. First paid upgrade: a content-optimization specialist — Surfer (Discovery at $49/month for testing, Standard at $99/month per its official page) or Clearscope — because structured optimization is this team’s recurring core workflow. Add a research platform second, when topic selection needs competitive data beyond free tools. Keep editorial judgment above optimization scores.

Local business. Foundation: Search Console for the website plus Moz’s free local listing audit tools for citation and listing accuracy. Paid upgrade: usually none at first — the evidence supports free listing checks as the starting point, and a paid multi-location tracking platform only becomes relevant when you manage several locations or owe recurring local reports. Evaluate that category against official documentation when the trigger arrives, since this corpus does not rank paid local platforms.

Agency or multi-client team. Foundation: Search Console access to every client property you can get verified. First paid upgrade: a consolidated platform with multi-site tracking and reporting — Marketer Milk identifies Semrush’s tracking-and-reporting workflow as “specifically designed for SEO agencies, freelancers managing multiple clients, and marketing teams,” and Semrush’s own positioning is that “agencies need tools that scale across multiple clients.” Add specialists per material gap: Screaming Frog licences for technical delivery (budgeting per user, with volume discounts from five licences), and a content tool if content production is a service line. Agencies feel per-seat and per-domain costs fastest — Ahrefs’ extra-user fees of $40–$80 per month by tier and whether Semrush AI capabilities require separately priced add-ons — and how those are billed — should be verified officially; such items are the kind of line items that turn an entry price into a very different invoice.

Technical SEO workflow. Foundation: Search Console plus Screaming Frog free. First paid upgrade: the Screaming Frog licence at $279 per year once sites exceed 500 URLs or you need scheduling, JavaScript rendering, and crawl comparison. A research platform is secondary here and only warranted when the role includes competitive analysis; a crawler and first-party data cover pure technical delivery.

Beyond tool selection, organizations should run a short procurement check before any contract, because these requirements rarely appear in editorial comparisons. Verify, in the vendor’s official terms rather than sales conversations: how many seats you actually need at the tier’s per-user rates; whether exports and API access are included or gated to higher tiers (Ahrefs meters export rows by plan, and Surfer reserves API access for its $299/month Peace of Mind tier, per their pricing pages); how long historical data is retained (6 months on Ahrefs Lite versus 5 years on Advanced); whether the tool integrates with your reporting and workflow systems, which Zapier’s criteria treat as decisive; regional and language coverage of the databases you depend on; and the vendor’s data-privacy and data-handling terms as they apply to your clients’ information. None of these should be assumed — confirm each in current official documentation, then buy the smallest stack that passes.