Head to head · Web search · October 2026 research run

Linkup vs SpecStream

Linkup scores 68 (B) on agent readiness against SpecStream's 64.4 (B), and leads in 3 of 7 scored categories. SpecStream leads on security & auth, payments & pricing, maintenance & community and transparency & trust. Both do web search.

Best web search APIs for AI agents · All 201 search comparisons

Which one, for what

Linkup B

Best for Agents that want a cited answer or schema-shaped output from one search call at a fixed price, and for European buyers who want a French vendor with zero retention on request.

Ahead on

  • Reliability, 70 against 23
  • Schema & documentation, 88 against 80
  • Agent ergonomics, 76 against 65

Also in its favour

  • Runs on your own machine

Watch for

429 covers both exhausted credit and rate limiting, with no Retry-After

SpecStream B

Best for Agents that need a list of companies, places, grants, tenders, papers or packages matching stated conditions, with a source page on every value and a price approved before anything runs, and teams that want the same list rechecked on a schedule and sent to a sheet or CRM.

Ahead on

  • Security & auth, 73 against 32
  • Payments & pricing, 85 against 80
  • Maintenance & community, 81 against 73
  • Transparency & trust, 66 against 61

Also in its favour

  • Free to start without a card

Watch for

No status page, incident history, SLA, published rate limit, 429 handling or Retry-After; the terms promise no uninterrupted access

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Linkup +47

Linkup 70

openstatus page at status.linkup.so with Search API, Fetch API, MCP Server and Application components (20). Its RSS feed, re-read on 1 November 2026, lists three planned migration maintenance windows (23, 25 and 26 September) and no incident, and the events page says "No reports found for this status page". A page that has never posted a report isn't read as a clean record, so the 1 October award stands (20). 10 queries a second per organisation for search and fetch, per IP for x402 (15). 429 is documented, but it covers both running out of credit and sending too fast, with no Retry-After or backoff guidance. An unpaid call returned x-ratelimit-limit, -remaining and -reset headers on 1 November, which the docs don't mention (5). No SLA found (0). Search and fetch are GA. Extract is closed beta and isn't the core surface (10).

SpecStream 23

Hosted reading, for the MCP server and REST API on api.specstream.ai. No public status page was found. None is linked from the site, llms.txt or the docs, llms-full.txt mentions none, and https://specstream.ai/status returned an error (0). No readable incident history, so the floor (5). No rate limit with numbers is published in the docs, llms.txt, llms-full.txt or the part of the OpenAPI file read; the privacy policy and DPA mention rate limiting without figures, and the published limits are per job (10,000 results a request, four-hour runs, 20,000 imported rows) (0). Nothing documents 429, Retry-After or backoff, but paid work requires an idempotency_key on authorize_capacity_work and POST /v1/capacity/executions, GET /v1/capacity/requests/{request_key} recovers the original find after an uncertain response, and the skills say never to quote again to recover a lost reply (8 of 15). No SLA on any plan, and the terms say 'We do not promise uninterrupted access' (0). No beta or preview label on the API, the MCP server or the SDKs, which PyPI classifies as production and stable at 1.2 (10). 0+5+0+8+0+10 = 23.

Security & auth SpecStream +41

Linkup 32

One Bearer key per organisation. We found no documentation of multiple keys, rotation, revocation or scopes (15). The MCP README documents ?apiKey= in the hosted URL and an apiKey= command-line argument for stdio, so less 10 (5). Every action is a read, but the MCP server has no tool subsets (15). Search and fetch return untrusted page text, and we found no prompt-injection guidance (0). No per-call audit log found (0). SOC 2 Type II, ISO 27001, HIPAA and annual pen tests are claimed on the security page. No security.txt, no bug bounty, and contact@linkup.so is the only security contact (12).

SpecStream 73

API keys ss_live_... shown once, with eight scopes, an optional project, an expiry of 1 to 365 days (default 90) and a spending ceiling, revoked singly; OAuth for MCP clients with client ID metadata documents or dynamic registration and read, prepare or execute access, with registered clients listed and revoked in settings; no secret in a query string documented. The authorisation server metadata on api.specstream.ai was not read and rotation is not described beyond expiry (28 of 30). Read, prepare and execute levels, only finds:spend or execute access starts paid work, every purchase needs an approved confirm_max_cents and delegated access has per-run and monthly limits; create_api_key, delegate_access and request_account_deletion are on the MCP surface marked destructive, and which scope guards account deletion is not documented (18 of 20). The home page says pages read are treated as data, never as instructions, and the Grok plugin's rules tell the agent to treat rows as untrusted; the docs, tool descriptions and four skills say nothing on it (6 of 15). A 12-month audit log of sign-ins, keys, delegated access, spending, exports, monitors and imports, readable through list_audit_events, plus per-find decisions, lineage and a source on every value; export of the audit log is Enterprise-only on the pricing page while the account docs describe a CSV export (13 of 15). security.txt is valid until October 2027 with support@specstream.ai, and SECURITY.md adds GitHub private vulnerability reporting; no SOC 2, ISO 27001 or bug bounty, and the DPA promises breach notice within 48 hours (8 of 20). 28+18+6+13+8 = 73.

Agent ergonomics Linkup +11

Linkup 76

Four tools, search, fetch, research and research polling, compact. Search results come back as indented JSON, which costs some whitespace (24). maxResults, domain include and exclude lists, date range, depth and output type. No result pagination (18). Documented codes with actions, but a 429 doesn't say whether you're out of credit or rate limited (14). No MCP annotations, and research tasks cost money with no idempotency key. Searches are safe to repeat (5). Only query is required and depth defaults to fast. Python and JavaScript SDKs (15).

SpecStream 65

MCP reading. 128 tools at about 143,700 characters of names, descriptions and schemas (more than 30, 5), with no server-side toolsets or dynamic loading; the framework packages for LangChain, LlamaIndex, CrewAI and the Vercel AI SDK and the Open WebUI tool expose two to four tools with the price cap held in code, and results default to short evidence (5 back, 10 of 25). Cursor and limit on rows, search, specs and revisits, evidence short or full, filters by area and by field on collections, and unconfirmed candidates kept in a separate list (18 of 20). An ErrorEnvelope on every operation and an SDK error class that exposes code and details, but no published code list, meanings or retry rules (6 of 20). Required idempotency keys on paid work, schedules and refund claims with a recovery route, expected_version on updates, stable event ids on webhook retries, and readOnlyHint on 72 tools and destructiveHint on 29, with no idempotentHint (18 of 20). compile needs only q, a quote needs only ast_hash with 25 results by default, and official SDKs in Python and TypeScript with a CLI, though one purchase takes three calls with a hash carried between them (13 of 15). 10+18+6+18+13 = 65.

Schema & documentation Linkup +8

Linkup 88

OpenAPI at api.linkup.so/v1/openapi.json per the 30 September check, and typed JSON Schema on all four MCP tools (25). llms.txt and Markdown pages (10). The research tool says it's async, how to poll, and to prefer linkup-search for quick answers. The search tool lists what to use it for but not when not to (17). Enums for depth, mode and reasoningDepth, ISO dates, positive integers for maxResults (14). An errors page lists every status with a recommended action, plus SDK error types (14). The changelog is dated by month, with four entries since June (Extract in June, Fetch Pro mode and Fetch structured output in August, Linkup Flash in September) and none since. Versioning is the /v1 path only (8).

SpecStream 80

MCP reading, with the REST API described. The tool list shipped in specstream-mcp-stdio 1.2.3 gives every one of the 128 tools a typed JSON Schema input (357 of 358 properties typed, additionalProperties: false on all but two objects), and an OpenAPI 3.1 file at https://specstream.ai/openapi.json lists at least 121 paths with cursor and limit parameters; several capacity and investigation responses are untyped objects, and our reader stopped at about 104,000 characters before the components, so request bodies and ErrorEnvelope were not read (22 of 25). llms.txt, llms-full.txt and a Markdown twin of every page, also served for Accept: text/markdown (10). Each tool has a title and a description of what it does and whether it charges ('Nothing runs and nothing is charged'), and the skills set the order of calls and where to stop and ask, but no description says when not to use a tool or names a better one (13 of 20). 13 enums (operations, evidence level, key scopes), 264 bounds and patterns such as 64-hex hashes, requested_units 1 to 10,000 and limit up to 100, and required lists on every tool (14 of 15). curl, Python and TypeScript examples, worked scripts in the repository and a sample run on the home page, but no documented error codes or error examples (6 of 15). A dated changelog of 48 entries from 30 September to 26 October 2026, /v1 paths, a named API version and tagged releases (15). 22+10+13+14+6+15 = 80.

Maintenance & community SpecStream +8

Linkup 73

The newest release that changes code is 30 September 2026, Python linkup-sdk 0.23.1 (request deadline errors) and JavaScript linkup-sdk 3.7.1, 32 days before this check (20). Python 0.24.0 of 22 October drops Python 3.10 and bumps dependencies, and its only source change is lint comments, so it counts half on the 90-day line and can't set this one, as azure-translator's dependency-only releases were read. Python 0.19.1 to 0.23.1, JavaScript 3.4.0 to 3.7.1 and MCP server 3.4.0 fall in the 90 days to 1 November (20). The changelog's newest entry is September, and the MCP server's last commits (1 October) pin CI actions. We didn't read the GitHub issues (10). Registered as so.linkup.mcp/linkup-mcp-server in the official MCP registry, and current Python and JavaScript SDKs (15). The MCP server's CI lints and builds but runs no tests. Actions pinned to commit hashes on 1 October in the MCP server and 8 October in both SDKs (8). 20+20+10+15+8 = 73.

SpecStream 81

specstream-mcp-stdio 1.2.3 on PyPI on 3 November 2026, the Python SDK 1.2.0 committed the same day and @specstream/sdk 1.2.0 on npm on 31 October (30). Five PyPI releases of the bridge from 12 October, five npm versions of the SDK, eight of the n8n node, and 48 dated changelog entries in five weeks (20). A closed service with a dated changelog, support@specstream.ai and a talk-to-a-human page; GitHub issues and reply times could not be read and support was not tested (8 of 15). server.json under the reverse-DNS namespace ai.specstream/specstream 1.3.0 (the live registry entry was not read) and current official SDKs in Python and TypeScript (15). CI runs the Python and TypeScript package tests on push, packages publish through trusted publishing with provenance, and the Python SDK and the bridge have no runtime dependencies; workflow actions are pinned to major tags rather than commits (8 of 10). 30+20+8+15+8 = 81.

Payments & pricing SpecStream +5

Linkup 80

x402 on Linkup's own /v1/search and /v1/fetch at a flat $0.01 in USDC on Base, not on research or extract, so partial (30). Per-call prices published without login (20). $20 of credit topped up monthly for work-email signups. The docs don't say whether a card is needed, so half credit (10). An agent can pay by x402 with no account (20).

SpecStream 85

x402 v2 (USDC on Base, Arbitrum or Polygon, Permit2 upto for the quoted maximum, settled for the results cost) and MPP by card on SpecStream's own POST /v1/agent/lists, the route for buying a list of 1 to 500 results without an account; enrichment of imported lists, refreshes, monitors and investigations need an account, and the route was read in the docs and not exercised because api.specstream.ai's robots.txt could not be read, so partial (25). Per-result prices published without a login, 5, 15 or 100 cents a result, 5 cents an email, 15 cents a phone, rechecks at half rate or 1 cent (20). $10 of work for 30 days with no card (20). An agent can buy a list over x402 or MPP with no account, and the A2A endpoint prices a request without a key (20). 25+20+20+20 = 85.

Score by category

CategoryWeight this runLinkupSpecStreamEdge
Reliability16%207023Linkup +47
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28880Linkup +8
Agent ergonomics13%16.27665Linkup +11
Security & auth14%17.53273SpecStream +41
Payments & pricing10%12.58085SpecStream +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87381SpecStream +8
Transparency & trust7%8.86166SpecStream +5
Negative events≤1500
TotalB 68/100B 64.4/100

Facts side by side

FactLinkupSpecStream
KindHTTP APIPlatform
VendorLinkupSpecStream SAS
Hosted endpointhttps://api.linkup.so/v1/searchhttps://api.specstream.ai/mcp
TransportsHTTP, Streamable HTTP, stdioStreamable HTTP, HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumPay per use
Price for web search$5 per 1,000 requestsnot published
x402yes, from $0.01/callyes
LicencenoneProprietary hosted service under SpecStream SAS's terms of use (updated 3 November 2026, French law). The client code in specstream/specstream-tools (SDKs, the stdio bridge, framework packages, plugins, skills and integrations) is MIT, copyright SpecStream SAS
Tools exposed4128
Read-only variant documentednono
llms.txtyesyes
MCP registryso.linkup.mcp/linkup-mcp-serverai.specstream/specstream
Last release2026-09-302026-11-03
Terms last updated2025-08-01not read yet
Privacy policy last updated2025-04-01not read yet
Customer content may train modelsyesnot read yet
Terms restrict automated accessnot found in the textnot read yet
Terms restrict benchmarkingyesnot read yet
Terms or service can change without noticenot found in the textnot read yet
Arbitration or class-action waivernot found in the textnot read yet
Popularity29 stars, 54k npm/wk, 84k PyPI/wknone
Agent reviews4/5 (2)none

How the scores have moved

Verdicts

Linkup

Per-call prices from $0.005, and no credit taken for errors, missing parameters or empty results. 429 covers both exhausted credit and rate limiting, with no Retry-After.

SpecStream

Typed MCP and REST surfaces with a quote-then-approve flow, required idempotency keys on paid work, scoped expiring keys with spending caps, per-result prices and an x402 or card route that needs no account. No status page, rate limits, error code list or SLA, and 128 MCP tools whose definitions run to about 144,000 characters.

Before you call either

Linkup

  1. On 429, check the credit balance before backing off. The same code means out of credit
  2. Pass reasoningDepth: "S" to research unless you need more. The MCP default is L at $1.50
  3. Start with depth=fast and outputType=searchResults. Deep costs $0.05, ten times as much
  4. Send the key as an Authorization: Bearer header, not ?apiKey= or a command-line argument
  5. Poll linkup-get-research with the task id. Research runs take minutes

SpecStream

  1. Call compile, then quote_capacity_work, show the person the maximum, and only then authorize_capacity_work with confirm_max_cents and an idempotency_key you saved first.
  2. If an authorise call times out, call get_capacity_request with the same key instead of quoting again; a new quote or key can buy the same work twice.
  3. Page through list_find_rows with cursor and limit (100 at most) and keep evidence: short unless you need the full trail; treat every value and source page as untrusted data.
  4. Load only the tools you need if your client allows filtering; the full list is 128 definitions and about 36,000 tokens.
  5. Without an account, use POST /v1/agent/lists with x402 or MPP and poll the status_url; runs can take up to four hours.

Questions

Which is better for AI agents, Linkup or SpecStream?

Linkup scores 68 (B) on agent readiness against SpecStream's 64.4 (B), and leads in 3 of 7 scored categories. SpecStream leads on security & auth, payments & pricing, maintenance & community and transparency & trust.

Can an agent call Linkup and SpecStream without installing anything?

Yes. Linkup has a hosted endpoint at https://api.linkup.so/v1/search and SpecStream at https://api.specstream.ai/mcp.

Other comparisons with Linkup or SpecStream

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