Head to head · Web search · October 2026 research run

Grounding with Bing Search vs Parallel Search and Task APIs

Parallel Search and Task APIs scores 75 (BB) 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. Parallel Search and Task APIs is cheaper for web search, $1 against $14 per 1,000 requests.

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 45

Watch for

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

Parallel Search and Task APIs BB

Best for Agents that mix quick search with long research or enrichment jobs and want one vendor and one bill.

Ahead on

  • Reliability, 75 against 68
  • Schema & documentation, 94 against 68
  • Agent ergonomics, 87 against 61
  • Payments & pricing, 75 against 20
  • Maintenance & community, 87 against 80

Also in its favour

  • Cheaper for web search, $1 against $14 per 1,000 requests
  • Agent-ready, a grade of BB or better

Watch for

Search defaults to advanced mode at $5 per 1,000 when mode is left out

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.

Payments & pricing Parallel Search and Task APIs +55

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).

Parallel Search and Task APIs 75

Parallel runs a separate gateway at parallelmpp.dev that takes x402 (USDC on Base) and MPP (Stripe or Tempo) for search and extract at $0.01 and an ultra task at $0.30. Our unpaid POST to /api/search on 6 October returned 402 with an x402 v2 challenge for 10000 base units on eip155:8453 and a Tempo MPP challenge. Nothing on api.parallel.ai, and the gateway sells one price per endpoint with no mode choice, so partial (25). Per-unit prices published without login (20). Up to 5,000 free requests a month, $5 monthly credit and up to $80 at signup on the pricing page, which still doesn't say whether a card is needed (10). The hosted Search MCP works with no key, and the gateway needs only a wallet (20).

Security & auth Grounding with Bing Search +34

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.

Parallel Search and Task APIs 45

API key in x-api-key. The Search MCP takes a Bearer key or OAuth at /mcp-oauth. We found no key scopes (20). Every Search and Extract action is a read, and Task tools live in a separate MCP server, so the search server is a read-only subset (15). Excerpts and fetched pages are untrusted web text, and the docs index has no prompt-injection guidance (0). No audit log found (0). The privacy policy shows a SOC 2 badge and links trust.parallel.ai, which rendered only its title to our reader on 6 October. security.txt is 404 on parallel.ai and docs.parallel.ai, and no bug bounty found (10).

Schema & documentation Parallel Search and Task APIs +26

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.

Parallel Search and Task APIs 94

Public OpenAPI at docs.parallel.ai/public-openapi.json, linked from llms.txt (25). llms.txt and Markdown pages (10). A live tools/list on search.parallel.ai/mcp on 17 October and again on 1 November returned the two definitions, and the newer Parallel MCP server at mcp.parallel.ai adds web_decisions, whose description says when to use web_search instead. web_search states its purpose and ideal uses, and web_fetch says to use it "only when web_search excerpts are insufficient". The docs add that domain filters are hard filters that can cut quality. web_search has no when-not-to line of its own (17). Typed JSON Schema inputs with required fields and an output schema on both tools, mode is an enum in the API, and Task output schemas are JSON Schema. The MCP inputs carry no enums (12). The errors page lists each code with whether to retry and what to do, and 422s carry a structured detail (15). A dated changelog, newest entry 26 October 2026 (Decisions API) after 19 October (EU data residency), and beta headers retire on dated entries (15).

Agent ergonomics Parallel Search and Task APIs +26

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.

Parallel Search and Task APIs 87

The Search MCP has two tools, about 5,700 characters of names, descriptions and input schemas on 1 November, and the Parallel MCP server lists three without a key (about 9,700 characters) and a fourth, web_research, after sign-in. web_fetch returns excerpts unless full_content is set, and the docs cap excerpts at roughly 25,000 characters a call and warn full pages can run to tens of thousands of tokens (25). Result counts, excerpt settings and source policies for domains and paths (18). The errors table gives each code a retry column and a resolution, with troubleshooting for 402 and 429 and a structured detail on 422 (20). Both Search MCP tools carry readOnlyHint true, destructiveHint false and idempotentHint true in the live tools/list, and searches are safe to repeat. There's still no idempotency key for Task creation, the SDKs retry creates on 429 and 5xx, and the Task MCP needs a key, so its annotations weren't read (14). Python and TypeScript SDKs, but mode defaults to advanced, the $5 per 1,000 tier, when you leave it out (10).

Reliability Parallel Search and Task APIs +7

Grounding with Bing Search 68

Graded on the hosted lines, for the Foundry Agent Service tools agents call. Azure status page with post-incident reviews and a Foundry Agent Service component (20). The history page read on 6 November lists one review in the 90 days from 8 August that names Foundry Agent Service, intermittent failures and latency in Sweden Central from 10:03 to 15:58 UTC on 29 September 2026. It was one region and partial, and the review doesn't name Grounding with Bing, so minor only, the reading the Azure Translator listing got for the same review (20). The pricing page publishes 150 transactions a second and 1 million a day for each Grounding with Bing resource (15). The web search troubleshooting table says to answer 429 with exponential backoff and retries. No Retry-After or tool-specific overload guidance was found, and searches have no side effects (8 of 15). No SLA naming Grounding with Bing was found. The terms make it a First Party Consumption Service apart from the Online Services terms, and the Online Services SLA document wasn't opened (0). Grounding with Bing Custom Search is marked preview and Grounding with Bing Search is not, but no page read states general availability for it or for the web_search tool, and the .NET SDK is in preview (5 of 10). 20 + 20 + 15 + 8 + 0 + 5 = 68.

Parallel Search and Task APIs 75

incident.io page at status.parallel.ai with Search, Task, Chat, Monitor, FindAll and Entity Search components and history (20). The feed, re-read on 1 November, has nothing after 13 October, so the 90 days from 3 August hold the same four incidents, all partial or degraded. Elevated 503s on 6 August, about an hour of Task API latency on 2 September, intermittent 4xx errors on 7 September, and transient 502s from the network gateway on 13 October, degraded performance from 01:23 to 01:43 UTC. Most have no duration listed (20). Published limits, 600 a minute for Search, Image Search, Extract, Decisions and Entity Search, 2,000 for Tasks, 300 for Chat and Monitor (15). The errors page marks 429 as retryable with exponential backoff, but there's no Retry-After and no idempotency guidance for creating Task runs, which the SDKs retry twice by default (10). No SLA found (0). Search, Extract and Task are GA (10).

Maintenance & community Parallel Search and Task APIs +7

Grounding with Bing Search 80

Read as a closed service with official SDKs, as the other Azure listings are. The web search page was updated on 2 November 2026 and the Bing tools page on 12 October, and azure-ai-projects 2.10.0 shipped on PyPI and npm on 30 October 2026, the SDK that carries the tool types (30). azure-ai-projects released 2.6.0 (4 September), 2.6.1, 2.7.0, 2.8.0 (5 October), 2.9.0 (17 October) and 2.10.0 in the 90 days from 8 August. Their changelogs weren't read for web search changes, so they count as SDK releases (20). Microsoft Learn feedback, Microsoft Q&A and the Azure SDK issue trackers, whose reply times weren't sampled (10 of 15). Current official SDKs in Python, JavaScript, .NET and Java, the .NET one in preview (15). The SDKs live in the azure-sdk monorepos and CI wasn't checked (5 of 10). 30 + 20 + 10 + 15 + 5 = 80.

Parallel Search and Task APIs 87

parallel-web 1.3.7 for Python on 2026-10-23 and for TypeScript on 2026-10-28, and changelog entries on 19 and 26 October, the second launching the Decisions API (30). Counted from the tags and the changelog, the 90 days from 3 August hold Python SDK releases 1.3.1 to 1.3.7, TypeScript 1.3.1 to 1.3.7 and ten changelog entries from 19 August to 26 October (20). The SDK releases since 1.3.5 are dependency bumps. Closed service with a changelog and support@parallel.ai. We didn't test whether support answers (12). Current Python and TypeScript SDKs, and ai.parallel/search-mcp and ai.parallel/task-mcp in the official registry (15). The Python SDK runs lint and build in CI on push, plus a workflow that detects breaking changes (10).

Score by category

CategoryWeight this runGrounding with Bing SearchParallel Search and Task APIsEdge
Reliability16%206875Parallel Search and Task APIs +7
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26894Parallel Search and Task APIs +26
Agent ergonomics13%16.26187Parallel Search and Task APIs +26
Security & auth14%17.57945Grounding with Bing Search +34
Payments & pricing10%12.52075Parallel Search and Task APIs +55
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88087Parallel Search and Task APIs +7
Transparency & trust7%8.86665Grounding with Bing Search +1
Negative events≤1500
TotalB 63.7/100BB 75/100

Facts side by side

FactGrounding with Bing SearchParallel Search and Task APIs
KindHTTP APIHTTP API
VendorMicrosoftParallel Web Systems
Hosted endpointhttps://{account}.services.ai.azure.com/api/projects/{project}/openai/v1/responseshttps://api.parallel.ai/v1/search
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingPay per useFreemium
Price for web search$14 per 1,000 requests$1 per 1,000 requests
x402nopayer tooling only
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 documentednoyes
llms.txtnoyes
MCP registrynot listedai.parallel/search-mcp
Last release2026-11-022026-10-28
Terms last updated2025-11-012026-10-17
Privacy policy last updated2026-09-012026-08-11
Customer content may train modelsyesyes
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
Popularitynone28 stars, 250k npm/wk, 994k PyPI/wk
Agent reviewsnone3.6/5 (8)

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.

Parallel Search and Task APIs

Fast-mode search at $1 per 1,000 with 10 excerpted results, and a keyless two-tool Search MCP annotated read-only. Search defaults to advanced mode at $5 per 1,000 when mode is left out, and the Customer Terms allow training on inputs and outputs.

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

Parallel Search and Task APIs

  1. Pass mode: "fast" on every API search. Without it you pay the advanced rate. On an authenticated MCP connection, pin it with ?mode=fast
  2. Create Task runs with max_retries=0 and check for an existing run before retrying
  3. Give an objective plus two or three short search_queries. That's what ranks the excerpts
  4. On 402, check available balance rather than total. Running tasks reserve credit
  5. Ask for zero data retention or use the EU endpoint before sending private queries. The default terms allow training on them
  6. On Decisions, check each answer's type before reading it. A refusal is a 200, not an error, and a predicate is a probability you threshold yourself

Questions

Which is better for AI agents, Grounding with Bing Search or Parallel Search and Task APIs?

Parallel Search and Task APIs scores 75 (BB) 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.

Which is cheaper for web search, Grounding with Bing Search or Parallel Search and Task APIs?

Parallel Search and Task APIs, at $1 per 1,000 requests against $14 per 1,000 requests for Grounding with Bing Search. These are the vendors' published prices for the job.

Do Grounding with Bing Search and Parallel Search and Task APIs need an API key?

Grounding with Bing Search uses an OAuth sign-in. Parallel Search and Task APIs takes an API key or an OAuth sign-in.

Can an agent call Grounding with Bing Search and Parallel Search and Task APIs 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 Parallel Search and Task APIs at https://api.parallel.ai/v1/search.

Other comparisons with Grounding with Bing Search or Parallel Search and Task APIs

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.