Moz API Alternatives: Cheap Domain Authority APIs Compared (2026)

You built something on the Moz API free tier — a lead scorer, a directory filter, a prospect-list enricher — and then you hit the wall. The wall is real, and it's low: as of September 2026, Moz's free tier allows roughly 50 rows per month, rate-limited to one request every 10 seconds. The paid ladder starts at $20/mo for 3,000 rows and climbs through $75/15K, $125/50K, $250/120K, and $500/500K rows, all the way to $10,000/mo for 40M.

If you're doing bulk domain-authority lookups — scoring lead lists, filtering link prospects, enriching a CRM — you need something that doesn't meter you by the row-month. This post compares the realistic options, including one that's completely free, with the pricing math done honestly. (Spoiler on the honesty: at exactly 3,000 lookups every single month, Moz's $20 tier is competitive. The interesting question is what happens every other month.)

First, what "domain authority" even means across vendors

There is no standard. Every vendor computes its own 0–100-ish score from its own link graph:

• Moz DA — the original, and still the industry-default vocabulary ("what's their DA?"). Computed from Moz's proprietary crawl.
• Majestic Trust Flow / Citation Flow — quality- and quantity-weighted scores from Majestic's index; the lingua franca of link marketplaces.
• RankParse Authority Score — computed from the open-data link graph (Common Crawl), the same upstream Google's research community uses. See DA vs DR explained for how these families differ.
• OpenPageRank — a PageRank-style metric on the Common Crawl host graph.

Scores from different vendors will disagree in absolute terms and correlate strongly in relative terms. For ranking and filtering — "which of these 10,000 domains are worth attention?" — any of them works. For reporting to a client who expects "DA" specifically, the vendor is part of the deliverable. Keep that in mind through the comparison.

The comparison

RankParse — 1 credit per lookup, no clock

A domain authority lookup costs 1 credit — $0.010 at the $10 Starter pack, $0.008 at Growth, $0.006 at Scale — with no subscription, no monthly reset, and no 10-second throttle (60 req/min on Starter, 300 on Growth). The first 100 lookups are free, no card.

Here's the honest math against Moz's $20 tier: 3,000 RankParse lookups cost $24–30 in credits. If you run exactly 3,000 lookups every month, Moz is marginally cheaper. The difference is the model: Moz bills $20 whether you run 3,000 lookups or zero, and unused rows evaporate at the billing cycle. RankParse credits are a one-time purchase that sits in your account until you spend it. Bursty and seasonal workloads — which is most lead-scoring and prospecting work — pay only in the months they actually run. Head-to-head on the whole product: RankParse vs Moz.

OpenPageRank — genuinely free, genuinely limited

OpenPageRank (now operated under Keywords Everywhere) gives you a PageRank-style score from the Common Crawl host graph, free at 1,000 requests per day with an API key. If a single open-data authority metric is your entire requirement and 1,000/day fits your pipeline, use it — you'll find it anyway, and it's good. What it doesn't have: backlinks, referring domains, anchors, tech stack, or any of the profile data behind the score. The moment you ask "why is this domain's score high?", you've outgrown it.

Moz — the default metric, priced by the row-month

If your clients or your product's users expect the number to be called "DA," Moz is the source of truth and the ladder is predictable: $20/mo (3K rows) → $500/mo (500K rows) → $10,000/mo (40M). Just know what you're buying: rows that reset monthly, on a subscription, from an index that's smaller and slower-moving than Ahrefs' or Majestic's.

Majestic — Trust Flow behind a $399.99/mo API gate

Majestic's Trust Flow is deeply embedded in link-buying workflows, but programmatic access at full fidelity means the API plan at $399.99/mo — the Lite ($49.99) and Pro ($99.99) plans are dashboard products. If TF/CF is a hard requirement, that's the toll. If any credible authority signal will do, it's a very expensive way to rank a lead list. See RankParse vs Majestic.

DataForSEO — PAYG, if you're already there

DataForSEO exposes domain-rank metrics through its Backlinks API at per-task + per-row PAYG pricing (backlinks requests are $0.024 plus $0.000036/row). If you already run DataForSEO integration with its Basic Auth and task envelopes, adding rank lookups is marginal. As the first integration just for authority scores, it's overbuilt. See RankParse vs DataForSEO.

The small authority-score vendors

There's a growing tail of small API vendors selling a single authority score (seoscoreapi and similar). Some are fine. Evaluate them the way you'd evaluate us: is the data source disclosed? Is pricing published? Is there a free tier to verify the scores correlate with something you trust? Open provenance is the whole reason to trust a non-Moz number.

The worked scenario: scoring a 10,000-domain lead list

A one-time enrichment job — score every domain in a lead export, as in our lead enrichment use case:

If time doesn't matter and one metric is enough, OpenPageRank wins on price forever. If you want the score plus the evidence behind it — referring domains, backlinks, tech stack — in the same API, at 60–300 requests/min instead of a daily cap, that's RankParse's job.

For lists, batch the calls. The Python SDK loop is the whole integration:

import os
from rankparse import RankParseClient

domains = ["stripe.com", "vercel.com", "linear.app"]  # scale to 10,000

with RankParseClient(api_key=os.environ["RANKPARSE_API_KEY"]) as client:
    for domain in domains:
        result = client.domain_authority(domain)  # 1 credit
        print(domain, result["data"]["score"])

Need backlink profiles alongside the scores? The batch endpoint pulls backlinks for up to 50 domains per request at 2 credits per domain.

When Moz is still the right choice

• Your clients expect "DA". If the metric's name is part of your deliverable — agency reports, marketplace listings — Moz is definitionally the source, and no alternative score substitutes.
• Your volume is steady and matches a tier. At a consistent 3,000 lookups every month, $20/mo is a fair price and the billing is simple.
• You need Spam Score. Moz's link-quality flag has no direct equivalent in the open-data options.

Otherwise, pay for lookups when you run them, not for months when you don't.

FAQ

Is there a free domain authority API?

Yes, two kinds. OpenPageRank is free at 1,000 requests/day (one open-data metric). RankParse gives 100 free credits with no card — enough for 100 authority lookups — and there's a free Domain Authority Checker for one-off checks in the browser. Moz's free tier exists but is capped around 50 rows/month at 1 request per 10 seconds.

How much does the Moz API cost after the free tier?

The paid ladder (as of September 2026): $20/mo for 3,000 rows, $75/15K, $125/50K, $250/120K, $500/500K, $2,000/4M, up to $10,000/mo for 40M rows. Rows reset monthly and don't roll over.

Are RankParse and Moz authority scores the same metric?

No. Both are 0–100 link-graph scores, but Moz DA comes from Moz's proprietary crawl and RankParse's Authority Score is computed from the open Common Crawl link graph. They correlate well for relative ranking; the absolute numbers differ. Never mix vendors' scores in one column of a report.

What's the cheapest way to score domain authority for 10,000 domains?

Free, if OpenPageRank's single metric and 1,000/day cap work for you (10 days). Fastest cheap option: RankParse at 10,000 credits — $80 as a one-time purchase, no subscription to cancel afterward, and leftover credits keep their value.

Do RankParse credits expire if I only run lookups occasionally?

No. Credits never expire. That's the core difference from every row-quota and unit-allowance model in this post: an occasional workload pays only for what it actually runs.

Outgrew the free tier? RankParse starts with 100 free credits — no card, no monthly fee, no 10-second throttle. Get your API key or try the free DA checker first.