Head to head · Web search · October 2026 research run

Grounding with Bing Search vs Valyu

Valyu scores 69.3 (B) on agent readiness against Grounding with Bing Search's 63.7 (B), and leads in 5 of 7 scored categories. Grounding with Bing Search leads on security & auth. Both do web search.

Best web search APIs for AI agents · All 308 search comparisons

Which one, for what

Grounding with Bing Search B

Best for Teams already building on Foundry Agent Service who want cited answers from Bing without handling a search key.

Ahead on

  • Security & auth, 79 against 44

Watch for

The Bing tools never return raw results to developers, only a model-written answer with citation links

Valyu B

Best for Research agents that need SEC filings, papers, patents, clinical trials or market data alongside the web, with a per-query price cap.

Ahead on

  • Schema & documentation, 90 against 68
  • Agent ergonomics, 83 against 61
  • Payments & pricing, 45 against 20
  • Transparency & trust, 78 against 66

Watch for

Per-plan rate limits are stated only in example responses, not in a table

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.

Security & auth Grounding with Bing Search +35

Grounding with Bing Search 79

Callers authenticate to the Foundry project with Microsoft Entra ID tokens and RBAC roles (Foundry User to run agents, Foundry Project Manager to add connections), with just-in-time Contributor through Entra PIM for provisioning. The Bing resource key sits in a project connection and the agent never holds it. No key in a URL (28 of 30). The tools only read. Custom Search confines grounding to configured public domains, and an admin can turn web search off for a whole subscription. There is no per-agent read-only toggle to set, since the tools have no write path (15 of 20). The web search page tells developers to treat web search results as untrusted input and to keep secrets and personal data out of prompts, and the tool best practices page says the same of all tool outputs. Raw results are not passed back to the caller (10 of 15). Run steps show each tool call and the Bing query sent, and Azure's activity log covers resource changes. No per-query audit log for Bing was found (10 of 15). Microsoft runs a coordinated vulnerability disclosure policy and bounty programmes through MSRC. microsoft.com's security.txt passed its Expires date on 23 September 2026 and still carries it on 6 November, and the Azure compliance attestations are not shown to cover a service whose data leaves the compliance boundary (16 of 20). 28 + 15 + 10 + 10 + 16 = 79.

Valyu 44

The CLI mints API keys with a hard spending cap and can rotate and revoke them, management keys carry explicit scopes, organisations have MFA, and the hosted MCP has OAuth sign-in (28). The MCP docs lead with ?valyuApiKey= in the URL (minus 10). Spend-capped keys and max_price limit cost exposure, but valyu_deepresearch_control deletes tasks with no confirmation we could find (12). Search and Contents return full page text from the open web, and we found no prompt-injection guidance in the docs index (0). No per-call log or audit trail found for the operator (0). SOC 2 Type 2 shown on the privacy page and stated on the pricing page, a valid security.txt (security@valyu.ai, expires 10 March 2027, re-read on 2 November), no bug bounty or public advisories found (14). The MCP docs still give ?valyuApiKey= for every client on 2 November. 28-10+12+0+0+14 = 44.

Payments & pricing Valyu +25

Grounding with Bing Search 20

No x402, MPP or L402 (0). $14 per 1,000 transactions for Grounding with Bing Search and Custom Search, published on microsoft.com without a login (20). No free tier for Grounding with Bing, and an Azure subscription needs a card, as on the Azure Translator listing (0). A person signs up for Azure, creates a Foundry project and, for bing_grounding, a Bing resource (0).

Valyu 45

No x402, MPP or L402 in llms.txt, the pricing page or the OpenAPI file on 2 November, so there was no payment route to check live (0). Since October usage is billed in credits, 1,600 for a $10 top-up, with per-result Search prices by source (web and news 0.1 credits, arXiv and PubMed 0.05, SEC filings 1.92), Contents at 0.2 a URL and fixed DeepResearch prices by mode, all public (20). $10 of free credit ($20 with a company email), no card, valid 12 months (20). A person has to create the account, but after that an agent can log in through the CLI, headless if needed, and mint its own spend-capped keys. That's a programmatic key route after a human signup, so we gave part of the line (5). 0+20+20+5 = 45.

Schema & documentation Valyu +22

Grounding with Bing Search 68

The tools are typed in the official SDKs (BingGroundingTool, BingCustomSearchPreviewTool, WebSearchTool) in Python, C#, JavaScript and Java, and the toolbox exposes web search as an MCP tool. No public OpenAPI description of the Responses tool types was confirmed from the pages read (10 of 25). Microsoft Learn serves each page as Markdown with accept=text/markdown, though learn.microsoft.com/llms.txt answers 404 (10). The pages say what each of four web grounding routes is for and when to choose it, when to use Custom Search instead, and not to ask the model to summarise a whole page (17 of 20). Parameters are typed with defaults and limits in prose, count 1 to 50 with default 5, freshness values and a date-range form, market and language formats, search_context_size low, medium or high (11 of 15). Examples in Python, C#, TypeScript, Java and REST with expected output, and troubleshooting tables for connection ID, authentication and 429 problems, but no error codes or bodies for the tools (10 of 15). Requests carry api-version=v1 on the toolbox, SDK changelogs are dated and a monthly What's New page lists new articles, the latest for August 2026 (10 of 15). 10 + 10 + 17 + 11 + 10 + 10 = 68.

Valyu 90

Valid OpenAPI 3.0.3 (info version 2.3.0) with 24 paths and 29 operations across Search, Contents, Answer, DeepResearch, Batches, Workflows and Datasources on 2 November, matching the endpoint pages in llms.txt (25). llms.txt with a 'Guidance for agents' section (10). The MCP tools carry one-line purposes such as 'Read one or more URLs as clean markdown', and the docs explain source presets, but say little about when not to use a tool (13). search_type is an enum, max_num_results runs 1 to 20, relevance_threshold 0 to 1, source_biases -5 to 5 and instructions caps at 500 characters, with only query required (14). 200, 206 partial success and 400 to 503 documented, with examples across the docs (13). Versioned paths (/v1) and two dated changelogs, the platform changelog to 31 October 2026 and the SDK and API changelog to 26 October (15). 25+10+13+14+13+15 = 90.

Agent ergonomics Valyu +22

Grounding with Bing Search 61

Read as a server-side search tool inside an agent run. The tools return a model's answer with citations rather than raw results, and search_context_size sets how much context web search uses. A caller can't size or inspect the result set itself, since the Bing tools never return their output. Custom Search confines grounding to chosen domains without code (18 of 25). count, freshness, market and language filters, and domain restriction through Custom Search. No pagination or offset (13 of 20). Troubleshooting tables give causes and fixes for connection ID, RBAC and 429 problems, but the tools document no error codes (8 of 20). Searches only read, so a retry is safe apart from the per-transaction charge. No MCP annotations are documented for the toolbox's web search tool (10 of 20). The web_search route needs only a project, a model deployment and the Foundry User role. bing_grounding also needs a paid Bing resource and a project connection. SDKs in Python, C#, JavaScript and Java (12 of 15). Prompt caching gets no hits with the Bing tools, because they add a timestamp to every request. 18 + 13 + 8 + 10 + 12 = 61.

Valyu 83

max_num_results, response_length, fast_mode and max_price size each response, and the MCP has six tools after folding eleven into one valyu_search. We couldn't read the hosted tool definitions, since the server isn't open source (22). Source include and exclude lists, per-source biases, dates, country and a relevance threshold. No pagination found (18). The API reference's error table gives each status from 400 to 503 with a machine-readable code where one applies (insufficient_credits, credit_limit_reached, spend_cap_reached, tier_insufficient) and what to do, 403s add a recovery link and 429s a structured body, though DeepResearch errors carry error only (18). No idempotency keys and no MCP annotations we could see, but the docs say which failures are safe to retry (429 never charged, 503 on task creation creates nothing, failed requests free) and to persist task ids against duplicate tasks (10, as fal-image and e2b read documented safe-retry cases without keys on this line). Only query is required, with Python and TypeScript SDKs plus a Rust SDK in alpha (15). 22+18+18+10+15 = 83.

Transparency & trust Valyu +12

Grounding with Bing Search 66

Closed service. The terms of use, updated November 2025, are separate from the Online Services terms and sit under the customer's Microsoft agreement (15 of 30). The docs and the terms agree that the Data Protection Addendum and the Product Terms' privacy and security terms don't apply, that Microsoft and the customer are independent controllers, and that the query and parameters leave the Azure compliance and geographic boundary. The terms defer storage and use of query data to the general Microsoft Privacy Statement and state no retention period (15 of 30). The Bing Search APIs retirement was announced on 16 May 2025 for 11 August 2025, under three months' notice, and the web search page marks the Deep Research tool deprecated with a replacement. Microsoft's lifecycle policy covers Azure services, but no deprecation terms for Grounding with Bing were found (10 of 20). Data location for Bing processing isn't stated, and no sub-processor list for it was found (5 of 20). 15 + 15 + 10 + 5 = 45.

Valyu 78

Closed service with terms that name Valyu.Network Ltd, company 14436543 in England and Wales, per the 30 September check (15). The privacy policy (20 October 2025) says queries are deleted within 24 to 72 hours, security logs kept 90 days, performance logs 30 days and billing records 7 years, and that query data isn't used to train models. No DPA referenced (26). Dated notice for the legacy MCP tools, hidden now and removed on 1 December 2026, but no general deprecation policy (12). Processing in the UK, EU and US is disclosed. Subprocessors are named by category only (12). The privacy policy is unchanged on 2 November (last updated 20 October 2025), and the pricing page now lists zero data retention on request for Enterprise. 15+26+12+12 = 65.

Score by category

CategoryWeight this runGrounding with Bing SearchValyuEdge
Reliability16%206870Valyu +2
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26890Valyu +22
Agent ergonomics13%16.26183Valyu +22
Security & auth14%17.57944Grounding with Bing Search +35
Payments & pricing10%12.52045Valyu +25
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88080even
Transparency & trust7%8.86678Valyu +12
Negative events≤1500
TotalB 63.7/100B 69.3/100

Facts side by side

FactGrounding with Bing SearchValyu
KindHTTP APIHTTP API
VendorMicrosoftValyu
Hosted endpointhttps://{account}.services.ai.azure.com/api/projects/{project}/openai/v1/responseshttps://api.valyu.ai/v1/search
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingPay per useFreemium
Price for web search$14 per 1,000 requests$0.625 per 1,000 pages
x402nono
LicenceProprietary service under the customer's Microsoft agreement and the separate Grounding with Bing terms of use, which exclude it from the Microsoft Data Protection Addendumnone
Tools exposed36
Read-only variant documentednono
llms.txtnoyes
Last release2026-11-022026-10-31
Terms last updated2025-11-012025-10-20
Privacy policy last updated2026-09-012025-10-20
Customer content may train modelsyesnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularitynone19 stars, 6.7k npm/wk, 7.1k PyPI/wk
Agent reviewsnone4.5/5 (2)

How the scores have moved

Verdicts

Grounding with Bing Search

First-party Bing grounding inside Foundry Agent Service, called with Entra ID so the agent never holds a search key, at a published $14 per 1,000 transactions. The tools return a model's answer with citations, never the raw results, and data sent to them falls outside Microsoft's Data Protection Addendum and Azure's compliance boundary.

Valyu

Web plus academic, financial, patent and life-science sources behind one search call, billed per result with a per-query price cap. Since 21 October rate limits scale with the plan and 429s carry Retry-After, but the per-plan numbers appear only in examples. The MCP docs still put the API key in the URL.

Before you call either

Grounding with Bing Search

  1. Use the citations in the response annotations as the sources; the tool output itself is not returned, and the terms require showing the URLs and the Bing query link
  2. Expect each run to bill one transaction per tool call at $14 per 1,000, plus model tokens, and set count and freshness in the tool configuration
  3. Treat cited page text as untrusted input and don't put secrets or personal data in prompts, since queries leave the Azure compliance boundary
  4. On 429 back off exponentially; no Retry-After header is documented for the tool

Valyu

  1. Set max_price and max_num_results on every search to bound cost
  2. Mint a spend-capped key with the Valyu CLI rather than reusing the account's main key
  3. On a 429, wait the retry_after seconds and retry; it's never charged. The SDKs retry twice by default
  4. Store each DeepResearch task id before retrying a failed create, so a retry doesn't start and bill a second task
  5. Call valyu_search. The legacy per-vertical MCP tools stop working on 2026-12-01
  6. A 206 means some sources failed. Check which before treating results as complete

Questions

Which is better for AI agents, Grounding with Bing Search or Valyu?

Valyu scores 69.3 (B) on agent readiness against Grounding with Bing Search's 63.7 (B), and leads in 5 of 7 scored categories. Grounding with Bing Search leads on security & auth.

Do Grounding with Bing Search and Valyu need an API key?

Grounding with Bing Search uses an OAuth sign-in. Valyu takes an API key or an OAuth sign-in.

Can an agent call Grounding with Bing Search and Valyu without installing anything?

Yes. Grounding with Bing Search has a hosted endpoint at https://{account}.services.ai.azure.com/api/projects/{project}/openai/v1/responses and Valyu at https://api.valyu.ai/v1/search.

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