Data API — ByTheMath
Licensed access to the ByTheMath data feed — CD & savings rates, loan rates (personal, auto, student, business & home), credit cards, 529 plans, brokerage cash rates, I-bond rates and full rate history. Verified at the source, with as-of dates. Free tier available.
What the API provides
The ByTheMath data API gives licensed publishers and developers programmatic access to the same verified data that powers YourBestSavings.com, YourBestCards.com and YourBestLoanRates.com. Every record includes verified rates, composite scores, source URLs, and last-verified dates — updated daily from institution disclosure pages.
The API is served from https://api.bythemath.com/v1/ and returns JSON; send your key as Authorization: Bearer <key>. All records reflect human-confirmed data only — no scanner output is published without a human review step. Every rate includes an apy_as_of field showing when it was last verified against the institution’s own site.
Access tiers
| Tier | What’s included | Rate limit | Price |
|---|---|---|---|
| Free | Daily top-rates snapshot (best nationally available CDs by term, high-yield savings & money markets — verified on bank sites) • market benchmarks: daily Treasury yield curve, T-bill auction results, FDIC national averages, prime & fed funds, SBA loan benchmarks, federal student loan rates • full I-bond rate history • transfer bonuses & partners • free rate widgets. | 1,000 req/day | $0 — available immediately Get free key → |
| Developer | Free tier + all deposit products (3,500+ CDs, savings, money market, checking & HSA accounts from 670+ institutions) with APY, term, scores, state eligibility, rate conditions and early-withdrawal penalties • brokered CD rates (Fidelity, Schwab, Vanguard) • all 529 plans (fees, state tax deductions, rules). | 5,000 req/day | $79/mo or $790/yr Monthly → · Annual → |
| Publisher | Developer tier + all loan rates (personal, auto, student & business loans, 775 home-loan rates) with scores and state availability • 160+ home lenders with lending footprints, NMLS & complaint data • brokerage & robo-advisor data (cash-sweep rates, fees, minimums) • 410 scored credit cards • HSA provider scores • full rate-history time series. | 25,000 req/day | $299/mo or $2,990/yr Monthly → · Annual → |
| Enterprise | Everything + webhook push events, bulk export, SLA, custom data pipelines and redistribution/white-label licensing. | Unlimited | From $1,500/mo Subscribe → |
Paid plans: your key is emailed instantly after checkout. · Free rate widgets for your site →
Get your free API key
Free tier · 1,000 requests/day · daily top rates, Treasury yields, T-bill auctions, national averages, benchmarks, I-bonds and transfer bonuses. Your key is emailed to you instantly.
Endpoints
apy_as_of. Filterable by product type, term, and status.type=hysa|money_market|cd and term=12.since=YYYY-MM-DD for history, type=10yr for one tenor. Source: U.S. Treasury.type=4-Week and since=YYYY-MM-DD. Source: Treasury Fiscal Data.term.state.type / state.type.rate_changed, product_added, and product_removed events. Delivered within minutes of a verified change being committed.Example response
A single deposit product record from /v1/deposits:
{
"product_id": "cd_popular_direct_6mo",
"institution": "Popular Direct",
"name": "Popular Direct CD 6-Month",
"product_type": "cd",
"apy": 4.10,
"term_months": 6,
"min_deposit": 10000,
"ewp_days": 180,
"no_penalty": false,
"fdic_insured": true,
"apy_as_of": "2026-10-02",
"status": "L",
"source_url": "https://www.populardirect.com/savings/cds/"
}Data quality and freshness
Every record reflects data verified against the institution’s own disclosure page. Records include an apy_as_of date. Each record also carries last_verified_at; as of October 2026, 97% of ranked products were re-verified within the last 30 days. Discontinued products are removed from results. No institution pays to appear in or be excluded from API results.
Rate changes are detected by an automated daily scan and confirmed by human review before being committed. This means changes typically appear in the API one to two days after the institution posts them. The product_rate_history endpoint provides the full audit trail of every change with before/after values and verification dates.
Licensing terms
API data is licensed for display and analysis only. Redistribution, resale, or white-labeling of raw data is not permitted without an Enterprise license agreement. Any public-facing display of ByTheMath data requires attribution — “Data: ByTheMath” with a link to bythemath.com. The attribution requirement applies to all tiers including Free.
Frequently asked questions
What data does the ByTheMath API provide?
Verified CD, savings, money market and checking rates (3,500+ deposit products from 670+ institutions), loan rates (personal, auto, student, business and 775 home-loan rates with lender footprints), scored credit-card data (410 cards), 529 plans, brokerage cash-sweep and fee data, brokered CD rates, I-bond rate history, HSA provider scores, transfer bonuses and partners, and full product rate history — the same data that powers YourBestSavings.com, YourBestCards.com and YourBestLoanRates.com. Every record includes a composite score, source URL, and an apy_as_of verification date.
What format does the ByTheMath API return?
JSON, from https://api.bythemath.com/v1/. Each response includes the rows plus your remaining daily requests (also in the X-RateLimit-Remaining header).
How often is the data updated?
Continuously, on a rolling schedule. Automated scans flag possible rate changes, and every change is confirmed against the institution’s own rate page before it is committed — a scanner flag alone never changes a rate. Every record carries the date it was last verified, so you can see exactly how fresh it is.
Is there a free tier?
Yes. The Free tier includes a daily snapshot of the top nationally available CD, savings and money market rates, plus market benchmarks (Treasury yield curve, T-bill auctions, FDIC national averages, prime and fed funds, SBA and federal student loan rates), the full I-bond rate history and transfer bonuses — 1,000 requests/day for $0, available immediately. Paid tiers add the full verified catalog (every product, filters, conditions, state eligibility and scores) and rate history — get a free key.
What are the API rate limits?
Free: 1,000 requests/day. Developer: 5,000/day. Publisher: 25,000/day. Enterprise: unlimited.
Can I redistribute or resell the data?
No. API data is licensed for display and analysis only; redistribution, resale, or white-labeling of raw data requires an Enterprise license agreement.
Is attribution required?
Yes. Any public-facing display of ByTheMath data must include attribution — “Data: ByTheMath” linked to bythemath.com — on every tier, including Free.
Get access
To request API access or discuss licensing, email contact@bythemath.com with your use case, expected request volume, and intended display context. Free tier keys are self-serve: get one with the form above and it arrives by email in seconds. Paid tiers are self-serve too — your key is emailed instantly after checkout.
Developer tier: subscribe monthly ($79) or pay annually ($790, 2 months free). Your API key is emailed instantly to the address used at checkout. Base URL: https://api.bythemath.com/v1/.
Publisher tier: subscribe monthly ($299) or annually ($2,990, 2 months free). Enterprise: subscribe ($1,500/mo), or email us for custom pipelines, bulk export and SLA terms.