Best Developer Tools APIs (2026)
Best Developer Tools APIs (2026) are ReefAPI category hubs for live JSON: developer tools APIs return structured data for developer workflows. ReefAPI offers 18 non-legal developer tools APIs behind one key, one credit pool and the same { ok, data, meta, error } envelope, with examples derived from the catalog and committed live snapshots.
Ranked Developer Tools API list
Ranked by catalog action count, then alphabetically for ties; legal-heavy engines are excluded.
| # | Engine | What it returns | Actions | Snapshot sample | Free tier | Landing |
|---|---|---|---|---|---|---|
| 1 | Stack Overflow | items[] (questions: id, title, body, score, tags, owner→author, link), site, attribution; meta... | 87 | title: Using async/await with a forEach loop | yes | View API |
| 2 | GitHub Developer Data | user{} — login, id, name, bio, company, blog, location, public_repos, followers, following, cre... | 39 | name: [redacted-name]; company: Linux Foundation | yes | View API |
| 3 | Developer Utilities | algo, hex, base64, base64url, length_bits, hmac (crc32/adler32: hex, decimal) | 21 | algo: sha256; hex: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9 | yes | View API |
| 4 | Generation | file{file_b64|download_token, filename, content_type=application/pdf, bytes, pages_hint, delive... | 21 | file: invoice.pdf | yes | View API |
| 5 | Product Hunt | posts[] (id, slug, name, tagline, upvotes, comments_count, daily/weekly/monthly_rank, topics, p... | 13 | name: Lovable | yes | View API |
| 6 | Email Deliverability & DNS Health | domain, score{score,grade,breakdown}, spf{}, dkim{}, dmarc{}, mx{}, bimi{}, mta_sts{}, tls_rpt{... | 12 | domain: google.com; score: 80 | yes | View API |
| 7 | Email Preflight | html_validity{parse_ok,warnings[]}, size{bytes,gmail_clip_risk,limit}, accessibility{missing_al... | 7 | html_validity: true; size: 89 | yes | View API |
| 8 | Package Registries | package{} — name, latest version, description, license, homepage, repository, keywords, maintai... | 7 | name: fastapi | yes | View API |
| 9 | Service Status & Incident | vendor, name, indicator, is_operational, description, raw_indicator, active_incident_count, upd... | 7 | name: GitHub | yes | View API |
| 10 | Vulnerability & Dependency Intelligence | package, ecosystem, version, vuln_count, severity_summary{by_severity:{critical,high,moderate,l... | 7 | package: org.apache.logging.log4j:log4j-core; ecosystem: Maven | yes | View API |
| 11 | Web Archive | snapshots[] (timestamp, datetime, original, mimetype, statuscode, digest, length, snapshot_url)... | 7 | snapshots: [redacted-phone]; count: 10 | yes | View API |
| 12 | Domain Risk | domain, registered, risk_score (0-100), risk_level (low|medium|elevated|high), reasons[] (plain... | 6 | domain: google.com; registered: true | yes | View API |
| 13 | MCP Server & Agent-Skill Registry | { results: [{id,name,title,type,description,github_url,license,version,transport[],status,updat... | 6 | title: Google Drive; name: [redacted-name] | yes | View API |
| 14 | Change-Detect | content_hash, structural_hash, text_hash, title, meta_description, main_content, normalized_tex... | 5 | title: Example Domain | yes | View API |
| 15 | Threat Intelligence | target, type, malicious (bool), verdict (clean|suspicious|malicious), score (0-100), sources[]... | 5 | target: https://github.com/; type: url | yes | View API |
| 16 | Web Extract | final_url, title, metadata{canonical,lang,site_name,author,published_at,og,...}, extraction{met... | 5 | title: Web scraping - Wikipedia | yes | View API |
| 17 | Package & Dependency Trust | package{name,ecosystem,version,description,homepage}, metadata{license{value,spdx,tier,risk_not... | 4 | generated_at: [redacted-phone]T17:19:42Z | yes | View API |
| 18 | Passive OSINT & Recon | domain, count, subdomains[] (sorted unique), source_matrix{host:[sources]}, sources{per-source... | 4 | domain: hackerone.com; subdomains: a.ns.hackerone.com | yes | View API |
What each Developer Tools API covers
Stack Overflow includes 87 actions (questions, question, answers). Stack Overflow The primary catalog return is items[] (questions: id, title, body, score, tags, owner→author, link), site, attribution; meta....
GitHub Developer Data includes 39 actions (user, user_repos, user_followers). GitHub Developer Data The primary catalog return is user{} — login, id, name, bio, company, blog, location, public_repos, followers, following, cre....
Developer Utilities includes 21 actions (hash, uuid, encode). Developer Utilities The primary catalog return is algo, hex, base64, base64url, length_bits, hmac (crc32/adler32: hex, decimal).
Generation includes 21 actions (pdf_render, pdf_from_html, pdf_from_url). Generation The primary catalog return is file{file_b64|download_token, filename, content_type=application/pdf, bytes, pages_hint, delive....
Product Hunt includes 13 actions (posts, post, reviews). Product Hunt The primary catalog return is posts[] (id, slug, name, tagline, upvotes, comments_count, daily/weekly/monthly_rank, topics, p....
Email Deliverability & DNS Health includes 12 actions (check, spf, dmarc). Email Deliverability & DNS Health The primary catalog return is domain, score{score,grade,breakdown}, spf{}, dkim{}, dmarc{}, mx{}, bimi{}, mta_sts{}, tls_rpt{....
Email Preflight includes 7 actions (audit_html, css_support, spam_score). Email Preflight The primary catalog return is html_validity{parse_ok,warnings[]}, size{bytes,gmail_clip_risk,limit}, accessibility{missing_al....
Package Registries includes 7 actions (package, versions, version). Package Registries The primary catalog return is package{} — name, latest version, description, license, homepage, repository, keywords, maintai....
Service Status & Incident includes 7 actions (status, incidents, components). Service Status & Incident The primary catalog return is vendor, name, indicator, is_operational, description, raw_indicator, active_incident_count, upd....
Vulnerability & Dependency Intelligence includes 7 actions (package_vulns, vuln_detail, advisory_search). Vulnerability & Dependency Intelligence The primary catalog return is package, ecosystem, version, vuln_count, severity_summary{by_severity:{critical,high,moderate,l....
Web Archive includes 7 actions (snapshots, available, history). Web Archive The primary catalog return is snapshots[] (timestamp, datetime, original, mimetype, statuscode, digest, length, snapshot_url)....
Domain Risk includes 6 actions (assess, age, parked). Domain Risk The primary catalog return is domain, registered, risk_score (0-100), risk_level (low|medium|elevated|high), reasons[] (plain....
MCP Server & Agent-Skill Registry includes 6 actions (search, server_detail, skill_detail). MCP Server & Agent-Skill Registry The primary catalog return is { results: [{id,name,title,type,description,github_url,license,version,transport[],status,updat....
Change-Detect includes 5 actions (snapshot, diff, monitor_check). Change-Detect The primary catalog return is content_hash, structural_hash, text_hash, title, meta_description, main_content, normalized_tex....
Threat Intelligence includes 5 actions (url_check, domain_reputation, ip_reputation). Threat Intelligence The primary catalog return is target, type, malicious (bool), verdict (clean|suspicious|malicious), score (0-100), sources[]....
Web Extract includes 5 actions (scrape, map, crawl). Web Extract The primary catalog return is final_url, title, metadata{canonical,lang,site_name,author,published_at,og,...}, extraction{met....
Package & Dependency Trust includes 4 actions (package_trust, repo_trust, lockfile_scan). Package & Dependency Trust The primary catalog return is package{name,ecosystem,version,description,homepage}, metadata{license{value,spdx,tier,risk_not....
Passive OSINT & Recon includes 4 actions (subdomains, domain, ip). Passive OSINT & Recon The primary catalog return is domain, count, subdomains[] (sorted unique), source_matrix{host:[sources]}, sources{per-source....
Questions about Developer Tools APIs
Which Developer Tools API is free?
Every Developer Tools API listed here can be tried with ReefAPI's free tier: 1,000 credits on signup, no card required. The current hub includes Stack Overflow, GitHub Developer Data, Developer Utilities, Generation, Product Hunt, Email Deliverability & DNS Health, Email Preflight, Package Registries, Service Status & Incident, Vulnerability & Dependency Intelligence, Web Archive, Domain Risk, MCP Server & Agent-Skill Registry, Change-Detect, Threat Intelligence, Web Extract, Package & Dependency Trust, Passive OSINT & Recon.
Do these Developer Tools APIs need login?
No source-site login is needed for the listed ReefAPI responses. You call ReefAPI with an x-api-key header, and each engine returns the standard JSON envelope.
How fresh is the Developer Tools data?
Production requests fetch live data through ReefAPI. The table's sample data point comes from the committed snapshot for each engine, and the sitemap uses catalog freshness for recrawling.
What is the best Developer Tools API to start with?
Stack Overflow appears first because this hub ranks engines by action count, then alphabetically for ties. Use that as a coverage signal, then choose the API whose returned fields match your workflow.